Alzheimer's & Cognition

Dietary intake of polyunsaturated fatty acids (PUFA), particularly omega 6, is associated with improved cognitive function in older adults, new research suggests.

The study provides important “pieces of the puzzle” of the diet and cognition connection, but the results aren’t “ready for prime time,” study investigator Roger S. McIntyre, MD, professor of psychiatry and pharmacology, University of Toronto, said in an interview.

“I don’t think we’re there yet when it comes to recommending supplementation to the general public,” said Dr. McIntyre, adding a larger “more compelling study” is needed.

The study was published online Jan. 14 in The American Journal of Geriatric Psychiatry.
 

Clinically meaningful?

Research shows that 25%-50% of community-dwelling adults aged 65-85 years have some cognitive impairment. Other evidence indicates cognition is affected by dietary fat intake.

Many lines of research show that alterations in lipid homeostasis can cause brain dysfunction, said Dr. McIntyre. “This shouldn’t surprise us because our brain is made up of protein, water, and fat.”

This new analysis used combined data from the 2011-2012 and 2013-2014 cycles of the National Health and Nutrition Examination Survey (NHANES), a series of ongoing cross-sectional surveys conducted by the Centers for Disease Control and Prevention. The data are collected in two phases, an in-home face-to-face interview and a physical examination.

Researchers obtained dietary intake information through two 24-hour dietary recall interviews. Dietary information included total energy (kcal/d), intakes in grams per day (g/d) of total fat, saturated fatty acid (SFAT), monounsaturated fatty acid (MUFA), PUFA, total omega-3 and total omega-6 fatty acids, and milligrams per day (mg/d) of cholesterol.

For cognitive function, the researchers used total and delayed recall scores of the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD), the animal fluency test, and the digit symbol substitution test (DSST).

The study included 2,253 adults aged 60 years and older (mean age, 69.4 years) and 51% were non-Hispanic White individuals.

After adjustment for age, sex, race/ethnicity, educational attainment, smoking status, alcohol consumption, income, and total energy, dietary intake of PUFA and omega-6 fatty acid was positively associated with DSST.

The DSST score increased about 0.06 standard deviation (SD) (about 1 score) with each SD increase in these fatty acids (8.8 g/d for PUFA and 7.9 g/d for omega-6) (P values were .02 for PUFA and .01 for omega-6).

However, it’s unclear what an improvement of 1 DSST score means clinically, said Dr. McIntyre. “The P value is significant, but how does that translate? Does this mean a person can now think more clearly or function better?”
 

‘Million dollar question’ remains unanswered

The fact that omega-6, considered neuroinflammatory, was associated with improved DSST score illustrates the complexity of this field, said Dr. McIntyre.

“We’re learning that when it comes to inflammation, many of the molecules in our brain that are implicated as anti-inflammatory can also be pro-inflammatory, so bad guys can be good guys and good guys can be bad guys.”

It speaks to the notion of homeostasis, he added. “Just like a seesaw; when you push this part down, that part goes up.”

The analysis showed the animal fluency score increased about 0.05 SD (around 0.3 score) with each SD (1.1 g/d) increase in dietary intake of omega-3.

There were no significant associations between other dietary fat intake and cognitive performance.

The researchers investigated the role of oxidative stress and antioxidant biomarkers (gamma glutamyl transpeptidase [GGT], bilirubin, uric acid, and vitamin D).

Cells produce oxidative radicals that are normally “mopped up” by our “innate antioxidant capability,” said Dr. McIntyre. “But in states of cognitive impairment, these oxidative stress markers accumulate and they exceed what the normal innate response is able to manage.”

The study showed GGT levels decreased with increased PUFA and omega-6 fatty acid intakes; levels of bilirubin decreased with increase in most dietary fat intakes; uric acid levels decreased with MUFA intake and omega-6/omega-3 ratio; and vitamin D levels increased with omega-3 fatty acid intake but decreased with SFAT intake.

Causal mediation analysis showed the association between dietary intake of fatty acids and DSST performance was partially mediated by GGT levels. However, Dr. McIntyre emphasized that this does not prove causality.

“The million dollar question is, is this the sole explanation for the association? In other words, is it the oxidative stress that caused the cognitive impairment and therefore correcting it improved it, or is it the case that oxidative stress is a proxy of other activities that are also taking place?”
 

A ‘plausible’ link

In an editorial, Candida Rebello, PhD, of the department of integrated physiology and molecular medicine at Pennington Biomedical Research Center, Baton Rouge, La., said the finding that omega-3 and omega-6 fatty acids are positively associated with cognition in older adults makes some sense.

She noted that aging is associated with an overt inflammatory phenotype, and evidence shows these fatty acids are precursors for bioactive molecules that play a role in self-limiting the acute inflammatory response.

Dr. Rebello said the positive association of omega-6 fatty acid with cognition shown in this study contrasts with the “common belief” that increasing dietary intake of these fatty acids enhances inflammation, but agreed the association is “plausible.”

She said it’s “essential” to determine “the underlying mechanisms that regulate the diverse features of inflammation and sort out the processes that protect from neuronal damage and those that contribute towards it.”

She noted the ratio of omega-6 to omega-3 is about 15:1 in the present day Western diet, as opposed to a 1:1 ratio in diets of the past. Omega-3 fatty acids are found in fish oil supplements and fatty fish like mackerel and salmon, while cereal, grains, and vegetable oil are sources of omega-6.

Attaining a measure of balance of fatty acids in the diet may be a “prudent approach,” said Dr. Rebello. “Substituting some meat entrées with fatty fish and polyunsaturated vegetable oils with monounsaturated fats such as olive oil are small changes that are likely to garner adherence.”

Dr. Rebello noted that the study used NHANES food intake data, which rely on participant self-report and so may not be accurate.

The study received funding from the MOE (Ministry of Education in China) Project of Humanities and Social Sciences and the Research Startup Fund of Southwest University. Dr. McIntyre has received research grant support from CIHR/GACD/Chinese National Natural Research Foundation and speaker/consultation fees from Lundbeck, Janssen, Purdue, Pfizer, Otsuka, Takeda, Neurocrine, Sunovion, Bausch Health, Novo Nordisk, Kris, Sanofi, Eisai, Intra-Cellular, NewBridge Pharmaceuticals, and AbbVie. He is a CEO of Braxia Scientific Corp.

A version of this article first appeared on Medscape.com.

Dietary intake of polyunsaturated fatty acids (PUFA), particularly omega 6, is associated with improved cognitive function in older adults, new research suggests.

The study provides important “pieces of the puzzle” of the diet and cognition connection, but the results aren’t “ready for prime time,” study investigator Roger S. McIntyre, MD, professor of psychiatry and pharmacology, University of Toronto, said in an interview.

“I don’t think we’re there yet when it comes to recommending supplementation to the general public,” said Dr. McIntyre, adding a larger “more compelling study” is needed.

The study was published online Jan. 14 in The American Journal of Geriatric Psychiatry.
 

Clinically meaningful?

Research shows that 25%-50% of community-dwelling adults aged 65-85 years have some cognitive impairment. Other evidence indicates cognition is affected by dietary fat intake.

Many lines of research show that alterations in lipid homeostasis can cause brain dysfunction, said Dr. McIntyre. “This shouldn’t surprise us because our brain is made up of protein, water, and fat.”

This new analysis used combined data from the 2011-2012 and 2013-2014 cycles of the National Health and Nutrition Examination Survey (NHANES), a series of ongoing cross-sectional surveys conducted by the Centers for Disease Control and Prevention. The data are collected in two phases, an in-home face-to-face interview and a physical examination.

Researchers obtained dietary intake information through two 24-hour dietary recall interviews. Dietary information included total energy (kcal/d), intakes in grams per day (g/d) of total fat, saturated fatty acid (SFAT), monounsaturated fatty acid (MUFA), PUFA, total omega-3 and total omega-6 fatty acids, and milligrams per day (mg/d) of cholesterol.

For cognitive function, the researchers used total and delayed recall scores of the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD), the animal fluency test, and the digit symbol substitution test (DSST).

The study included 2,253 adults aged 60 years and older (mean age, 69.4 years) and 51% were non-Hispanic White individuals.

After adjustment for age, sex, race/ethnicity, educational attainment, smoking status, alcohol consumption, income, and total energy, dietary intake of PUFA and omega-6 fatty acid was positively associated with DSST.

The DSST score increased about 0.06 standard deviation (SD) (about 1 score) with each SD increase in these fatty acids (8.8 g/d for PUFA and 7.9 g/d for omega-6) (P values were .02 for PUFA and .01 for omega-6).

However, it’s unclear what an improvement of 1 DSST score means clinically, said Dr. McIntyre. “The P value is significant, but how does that translate? Does this mean a person can now think more clearly or function better?”
 

‘Million dollar question’ remains unanswered

The fact that omega-6, considered neuroinflammatory, was associated with improved DSST score illustrates the complexity of this field, said Dr. McIntyre.

“We’re learning that when it comes to inflammation, many of the molecules in our brain that are implicated as anti-inflammatory can also be pro-inflammatory, so bad guys can be good guys and good guys can be bad guys.”

It speaks to the notion of homeostasis, he added. “Just like a seesaw; when you push this part down, that part goes up.”

The analysis showed the animal fluency score increased about 0.05 SD (around 0.3 score) with each SD (1.1 g/d) increase in dietary intake of omega-3.

There were no significant associations between other dietary fat intake and cognitive performance.

The researchers investigated the role of oxidative stress and antioxidant biomarkers (gamma glutamyl transpeptidase [GGT], bilirubin, uric acid, and vitamin D).

Cells produce oxidative radicals that are normally “mopped up” by our “innate antioxidant capability,” said Dr. McIntyre. “But in states of cognitive impairment, these oxidative stress markers accumulate and they exceed what the normal innate response is able to manage.”

The study showed GGT levels decreased with increased PUFA and omega-6 fatty acid intakes; levels of bilirubin decreased with increase in most dietary fat intakes; uric acid levels decreased with MUFA intake and omega-6/omega-3 ratio; and vitamin D levels increased with omega-3 fatty acid intake but decreased with SFAT intake.

Causal mediation analysis showed the association between dietary intake of fatty acids and DSST performance was partially mediated by GGT levels. However, Dr. McIntyre emphasized that this does not prove causality.

“The million dollar question is, is this the sole explanation for the association? In other words, is it the oxidative stress that caused the cognitive impairment and therefore correcting it improved it, or is it the case that oxidative stress is a proxy of other activities that are also taking place?”
 

A ‘plausible’ link

In an editorial, Candida Rebello, PhD, of the department of integrated physiology and molecular medicine at Pennington Biomedical Research Center, Baton Rouge, La., said the finding that omega-3 and omega-6 fatty acids are positively associated with cognition in older adults makes some sense.

She noted that aging is associated with an overt inflammatory phenotype, and evidence shows these fatty acids are precursors for bioactive molecules that play a role in self-limiting the acute inflammatory response.

Dr. Rebello said the positive association of omega-6 fatty acid with cognition shown in this study contrasts with the “common belief” that increasing dietary intake of these fatty acids enhances inflammation, but agreed the association is “plausible.”

She said it’s “essential” to determine “the underlying mechanisms that regulate the diverse features of inflammation and sort out the processes that protect from neuronal damage and those that contribute towards it.”

She noted the ratio of omega-6 to omega-3 is about 15:1 in the present day Western diet, as opposed to a 1:1 ratio in diets of the past. Omega-3 fatty acids are found in fish oil supplements and fatty fish like mackerel and salmon, while cereal, grains, and vegetable oil are sources of omega-6.

Attaining a measure of balance of fatty acids in the diet may be a “prudent approach,” said Dr. Rebello. “Substituting some meat entrées with fatty fish and polyunsaturated vegetable oils with monounsaturated fats such as olive oil are small changes that are likely to garner adherence.”

Dr. Rebello noted that the study used NHANES food intake data, which rely on participant self-report and so may not be accurate.

The study received funding from the MOE (Ministry of Education in China) Project of Humanities and Social Sciences and the Research Startup Fund of Southwest University. Dr. McIntyre has received research grant support from CIHR/GACD/Chinese National Natural Research Foundation and speaker/consultation fees from Lundbeck, Janssen, Purdue, Pfizer, Otsuka, Takeda, Neurocrine, Sunovion, Bausch Health, Novo Nordisk, Kris, Sanofi, Eisai, Intra-Cellular, NewBridge Pharmaceuticals, and AbbVie. He is a CEO of Braxia Scientific Corp.

A version of this article first appeared on Medscape.com.

Dietary intake of polyunsaturated fatty acids (PUFA), particularly omega 6, is associated with improved cognitive function in older adults, new research suggests.

The study provides important “pieces of the puzzle” of the diet and cognition connection, but the results aren’t “ready for prime time,” study investigator Roger S. McIntyre, MD, professor of psychiatry and pharmacology, University of Toronto, said in an interview.

“I don’t think we’re there yet when it comes to recommending supplementation to the general public,” said Dr. McIntyre, adding a larger “more compelling study” is needed.

The study was published online Jan. 14 in The American Journal of Geriatric Psychiatry.
 

Clinically meaningful?

Research shows that 25%-50% of community-dwelling adults aged 65-85 years have some cognitive impairment. Other evidence indicates cognition is affected by dietary fat intake.

Many lines of research show that alterations in lipid homeostasis can cause brain dysfunction, said Dr. McIntyre. “This shouldn’t surprise us because our brain is made up of protein, water, and fat.”

This new analysis used combined data from the 2011-2012 and 2013-2014 cycles of the National Health and Nutrition Examination Survey (NHANES), a series of ongoing cross-sectional surveys conducted by the Centers for Disease Control and Prevention. The data are collected in two phases, an in-home face-to-face interview and a physical examination.

Researchers obtained dietary intake information through two 24-hour dietary recall interviews. Dietary information included total energy (kcal/d), intakes in grams per day (g/d) of total fat, saturated fatty acid (SFAT), monounsaturated fatty acid (MUFA), PUFA, total omega-3 and total omega-6 fatty acids, and milligrams per day (mg/d) of cholesterol.

For cognitive function, the researchers used total and delayed recall scores of the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD), the animal fluency test, and the digit symbol substitution test (DSST).

The study included 2,253 adults aged 60 years and older (mean age, 69.4 years) and 51% were non-Hispanic White individuals.

After adjustment for age, sex, race/ethnicity, educational attainment, smoking status, alcohol consumption, income, and total energy, dietary intake of PUFA and omega-6 fatty acid was positively associated with DSST.

The DSST score increased about 0.06 standard deviation (SD) (about 1 score) with each SD increase in these fatty acids (8.8 g/d for PUFA and 7.9 g/d for omega-6) (P values were .02 for PUFA and .01 for omega-6).

However, it’s unclear what an improvement of 1 DSST score means clinically, said Dr. McIntyre. “The P value is significant, but how does that translate? Does this mean a person can now think more clearly or function better?”
 

‘Million dollar question’ remains unanswered

The fact that omega-6, considered neuroinflammatory, was associated with improved DSST score illustrates the complexity of this field, said Dr. McIntyre.

“We’re learning that when it comes to inflammation, many of the molecules in our brain that are implicated as anti-inflammatory can also be pro-inflammatory, so bad guys can be good guys and good guys can be bad guys.”

It speaks to the notion of homeostasis, he added. “Just like a seesaw; when you push this part down, that part goes up.”

The analysis showed the animal fluency score increased about 0.05 SD (around 0.3 score) with each SD (1.1 g/d) increase in dietary intake of omega-3.

There were no significant associations between other dietary fat intake and cognitive performance.

The researchers investigated the role of oxidative stress and antioxidant biomarkers (gamma glutamyl transpeptidase [GGT], bilirubin, uric acid, and vitamin D).

Cells produce oxidative radicals that are normally “mopped up” by our “innate antioxidant capability,” said Dr. McIntyre. “But in states of cognitive impairment, these oxidative stress markers accumulate and they exceed what the normal innate response is able to manage.”

The study showed GGT levels decreased with increased PUFA and omega-6 fatty acid intakes; levels of bilirubin decreased with increase in most dietary fat intakes; uric acid levels decreased with MUFA intake and omega-6/omega-3 ratio; and vitamin D levels increased with omega-3 fatty acid intake but decreased with SFAT intake.

Causal mediation analysis showed the association between dietary intake of fatty acids and DSST performance was partially mediated by GGT levels. However, Dr. McIntyre emphasized that this does not prove causality.

“The million dollar question is, is this the sole explanation for the association? In other words, is it the oxidative stress that caused the cognitive impairment and therefore correcting it improved it, or is it the case that oxidative stress is a proxy of other activities that are also taking place?”
 

A ‘plausible’ link

In an editorial, Candida Rebello, PhD, of the department of integrated physiology and molecular medicine at Pennington Biomedical Research Center, Baton Rouge, La., said the finding that omega-3 and omega-6 fatty acids are positively associated with cognition in older adults makes some sense.

She noted that aging is associated with an overt inflammatory phenotype, and evidence shows these fatty acids are precursors for bioactive molecules that play a role in self-limiting the acute inflammatory response.

Dr. Rebello said the positive association of omega-6 fatty acid with cognition shown in this study contrasts with the “common belief” that increasing dietary intake of these fatty acids enhances inflammation, but agreed the association is “plausible.”

She said it’s “essential” to determine “the underlying mechanisms that regulate the diverse features of inflammation and sort out the processes that protect from neuronal damage and those that contribute towards it.”

She noted the ratio of omega-6 to omega-3 is about 15:1 in the present day Western diet, as opposed to a 1:1 ratio in diets of the past. Omega-3 fatty acids are found in fish oil supplements and fatty fish like mackerel and salmon, while cereal, grains, and vegetable oil are sources of omega-6.

Attaining a measure of balance of fatty acids in the diet may be a “prudent approach,” said Dr. Rebello. “Substituting some meat entrées with fatty fish and polyunsaturated vegetable oils with monounsaturated fats such as olive oil are small changes that are likely to garner adherence.”

Dr. Rebello noted that the study used NHANES food intake data, which rely on participant self-report and so may not be accurate.

The study received funding from the MOE (Ministry of Education in China) Project of Humanities and Social Sciences and the Research Startup Fund of Southwest University. Dr. McIntyre has received research grant support from CIHR/GACD/Chinese National Natural Research Foundation and speaker/consultation fees from Lundbeck, Janssen, Purdue, Pfizer, Otsuka, Takeda, Neurocrine, Sunovion, Bausch Health, Novo Nordisk, Kris, Sanofi, Eisai, Intra-Cellular, NewBridge Pharmaceuticals, and AbbVie. He is a CEO of Braxia Scientific Corp.

A version of this article first appeared on Medscape.com.

The American Heart Association (AHA) draws attention to the important bidirectional link between cardiovascular health and brain health in its annual statistical update on heart disease and stroke.

“For several years now, the AHA and the scientific community have increasingly recognized the connections between cardiovascular health and brain health, so it was time for us to cement this into its own chapter, which we highlight as the brain health chapter,” Connie W. Tsao, MD, MPH, chair of the statistical update writing group, with Harvard Medical School, Boston, said in an AHA podcast.

“The global rate of brain disease is quickly outpacing heart disease,” Mitchell S. V. Elkind, MD, immediate past president of the AHA, added in a news release.

“The rate of deaths from Alzheimer’s disease and other dementias rose more than twice as much in the past decade compared to the rate of deaths from heart disease, and that is something we must address,” said Dr. Elkind, with Columbia University Vagelos College of Physicians and Surgeons in New York.

“It’s becoming more evident that reducing vascular disease risk factors can make a real difference in helping people live longer, healthier lives, free of heart disease and brain disease,” Dr. Elkind added.

The AHA’s Heart Disease and Stroke Statistics – 2022 Update was published online January 26 in Circulation).

The report highlights some of the research connecting heart and brain health, including the following:

• A meta-analysis of 139 studies showed that people with midlife hypertension were five times more likely to experience impairment on global cognition and about twice as likely to experience reduced executive function, dementia, and Alzheimer’s disease.
• A meta-analysis of four longitudinal studies found that the risk for dementia associated with heart failure was increased nearly twofold.
• In the large prospective Atherosclerosis Risk in Communities (ARIC) Neurocognitive Study, atrial fibrillation was associated with greater cognitive decline and dementia over 20 years.
• A meta-analysis of 10 prospective studies (including 24,801 participants) showed that coronary heart disease (CHD) was associated with a 40% increased risk of poor cognitive outcomes, including dementia, cognitive impairment, or cognitive decline.

“This new chapter on brain health was a critical one to add,” Dr. Tsao said in the news release.

“The data we’ve collected brings to light the strong correlations between heart health and brain health and makes it an easy story to tell -- what’s good for the heart is good for the brain,” Dr. Tsao added.

Along with the new chapter on brain health, the 2022 statistical update provides the latest statistics and heart disease and stroke. Among the highlights:

• Cardiovascular disease (CVD) remains the leading cause of death worldwide. In the United States in 2019, CVD, listed as the underlying cause of death, accounted for 874,613 deaths, about 2,396 deaths each day. On average, someone dies of CVD every 36 seconds.
• CVD claims more lives each year in the United States than all forms of cancer and chronic lower respiratory disease combined.
• In 2019, CHD was the leading cause (41.3%) of deaths attributable to CVD, followed by other CVD (17.3%), stroke (17.2%), hypertension (11.7%), heart failure (9.9%), and diseases of the arteries (2.8%).
• In 2019, stroke accounted for roughly 1 in every 19 deaths in the United States. On average, someone in the United States has a stroke every 40 seconds and someone dies of stroke every 3 minutes 30 seconds. When considered separately from other CVD, stroke ranks number five among all causes of death in the United States.

While the annual statistics update aims to be a contemporary update of annual heart disease and stroke statistics over the past year, it also examines trends over time, Dr. Tsao explains in the podcast.

“One noteworthy point is that we saw a decline in the rate of cardiovascular mortality over the past three decades or so until about 2010. But over the past decade now, we’re also seeing a rise in these numbers,” she said.

This could be due to rising rates of obesity, diabetes, and poor hypertension control, as well as other lifestyle behaviors, Tsao said.
 

Key risk factor data

Each year, the statistical update gauges the cardiovascular health of Americans by tracking seven key health factors and behaviors that increase risk for heart disease and stroke. Below is a snapshot of the latest risk factor data.

Smoking

In 2019, smoking was the leading risk factor for years of life lost to premature death and the third leading risk factor for years of life lived with disability or injury.

According to the 2020 surgeon general’s report on smoking cessation, more than 480,000 Americans die as a result of cigarette smoking, and more than 41,000 die of secondhand smoke exposure each year (roughly 1 in 5 deaths annually).

One in 7 adults are current smokers, 1 in 6 female adults are current smokers, and 1 in 5 high school students use e-cigarettes.
 

Physical inactivity

In 2018, 25.4% of U.S. adults did not engage in leisure-time physical activity, and only 24.0% met the 2018 Physical Activity Guidelines for Americans for both aerobic and muscle strengthening.

Among U.S. high school students in 2019, only 44.1% were physically active for 60 minutes or more on at least 5 days of the week.
 

Nutrition

While there is some evidence that Americans are improving their diet, fewer than 10% of U.S. adults met guidelines for whole grain, whole fruit, and nonstarchy vegetable consumption each day in 2017–2018.

Overweight/obesity

The prevalence of obesity among adults increased from 1999–2000 through 2017–2018 from 30.5% to 42.4%. Overall prevalence of obesity and severe obesity in U.S. youth 2 to 19 years of age increased from 13.9% to 19.3% and 2.6% to 6.1% between 1999–2000 and 2017–2018.

Cholesterol

Close to 94 million (38.1%) U.S. adults have total cholesterol of 200 mg/dL or higher, according to 2015–2018 data; about 28.0 million (11.5%) have total cholesterol of 240 mg/dL or higher; and 27.8% have high levels of low-density lipoprotein cholesterol (130 mg/dL or higher).

Diabetes

In 2019, 87,647 U.S. deaths were attributed to diabetes; data show that 9.8 million U.S. adults have undiagnosed diabetes, 28.2 million have diagnosed diabetes, and 113.6 million have prediabetes.

Hypertension

A total of 121.5 million (47.3%) U.S. adults have hypertension, based on 2015–2018 data. In 2019, 102,072 U.S. deaths were primarily attributable to hypertension.

This statistical update was prepared by a volunteer writing group on behalf of the American Heart Association Council on Epidemiology and Prevention Statistics Committee and Stroke Statistics Subcommittee. Disclosures for the writing committee are listed with the original article.



A version of this article first appeared on Medscape.com.

The American Heart Association (AHA) draws attention to the important bidirectional link between cardiovascular health and brain health in its annual statistical update on heart disease and stroke.

“For several years now, the AHA and the scientific community have increasingly recognized the connections between cardiovascular health and brain health, so it was time for us to cement this into its own chapter, which we highlight as the brain health chapter,” Connie W. Tsao, MD, MPH, chair of the statistical update writing group, with Harvard Medical School, Boston, said in an AHA podcast.

“The global rate of brain disease is quickly outpacing heart disease,” Mitchell S. V. Elkind, MD, immediate past president of the AHA, added in a news release.

“The rate of deaths from Alzheimer’s disease and other dementias rose more than twice as much in the past decade compared to the rate of deaths from heart disease, and that is something we must address,” said Dr. Elkind, with Columbia University Vagelos College of Physicians and Surgeons in New York.

“It’s becoming more evident that reducing vascular disease risk factors can make a real difference in helping people live longer, healthier lives, free of heart disease and brain disease,” Dr. Elkind added.

The AHA’s Heart Disease and Stroke Statistics – 2022 Update was published online January 26 in Circulation).

The report highlights some of the research connecting heart and brain health, including the following:

• A meta-analysis of 139 studies showed that people with midlife hypertension were five times more likely to experience impairment on global cognition and about twice as likely to experience reduced executive function, dementia, and Alzheimer’s disease.
• A meta-analysis of four longitudinal studies found that the risk for dementia associated with heart failure was increased nearly twofold.
• In the large prospective Atherosclerosis Risk in Communities (ARIC) Neurocognitive Study, atrial fibrillation was associated with greater cognitive decline and dementia over 20 years.
• A meta-analysis of 10 prospective studies (including 24,801 participants) showed that coronary heart disease (CHD) was associated with a 40% increased risk of poor cognitive outcomes, including dementia, cognitive impairment, or cognitive decline.

“This new chapter on brain health was a critical one to add,” Dr. Tsao said in the news release.

“The data we’ve collected brings to light the strong correlations between heart health and brain health and makes it an easy story to tell -- what’s good for the heart is good for the brain,” Dr. Tsao added.

Along with the new chapter on brain health, the 2022 statistical update provides the latest statistics and heart disease and stroke. Among the highlights:

• Cardiovascular disease (CVD) remains the leading cause of death worldwide. In the United States in 2019, CVD, listed as the underlying cause of death, accounted for 874,613 deaths, about 2,396 deaths each day. On average, someone dies of CVD every 36 seconds.
• CVD claims more lives each year in the United States than all forms of cancer and chronic lower respiratory disease combined.
• In 2019, CHD was the leading cause (41.3%) of deaths attributable to CVD, followed by other CVD (17.3%), stroke (17.2%), hypertension (11.7%), heart failure (9.9%), and diseases of the arteries (2.8%).
• In 2019, stroke accounted for roughly 1 in every 19 deaths in the United States. On average, someone in the United States has a stroke every 40 seconds and someone dies of stroke every 3 minutes 30 seconds. When considered separately from other CVD, stroke ranks number five among all causes of death in the United States.

While the annual statistics update aims to be a contemporary update of annual heart disease and stroke statistics over the past year, it also examines trends over time, Dr. Tsao explains in the podcast.

“One noteworthy point is that we saw a decline in the rate of cardiovascular mortality over the past three decades or so until about 2010. But over the past decade now, we’re also seeing a rise in these numbers,” she said.

This could be due to rising rates of obesity, diabetes, and poor hypertension control, as well as other lifestyle behaviors, Tsao said.
 

Key risk factor data

Each year, the statistical update gauges the cardiovascular health of Americans by tracking seven key health factors and behaviors that increase risk for heart disease and stroke. Below is a snapshot of the latest risk factor data.

Smoking

In 2019, smoking was the leading risk factor for years of life lost to premature death and the third leading risk factor for years of life lived with disability or injury.

According to the 2020 surgeon general’s report on smoking cessation, more than 480,000 Americans die as a result of cigarette smoking, and more than 41,000 die of secondhand smoke exposure each year (roughly 1 in 5 deaths annually).

One in 7 adults are current smokers, 1 in 6 female adults are current smokers, and 1 in 5 high school students use e-cigarettes.
 

Physical inactivity

In 2018, 25.4% of U.S. adults did not engage in leisure-time physical activity, and only 24.0% met the 2018 Physical Activity Guidelines for Americans for both aerobic and muscle strengthening.

Among U.S. high school students in 2019, only 44.1% were physically active for 60 minutes or more on at least 5 days of the week.
 

Nutrition

While there is some evidence that Americans are improving their diet, fewer than 10% of U.S. adults met guidelines for whole grain, whole fruit, and nonstarchy vegetable consumption each day in 2017–2018.

Overweight/obesity

The prevalence of obesity among adults increased from 1999–2000 through 2017–2018 from 30.5% to 42.4%. Overall prevalence of obesity and severe obesity in U.S. youth 2 to 19 years of age increased from 13.9% to 19.3% and 2.6% to 6.1% between 1999–2000 and 2017–2018.

Cholesterol

Close to 94 million (38.1%) U.S. adults have total cholesterol of 200 mg/dL or higher, according to 2015–2018 data; about 28.0 million (11.5%) have total cholesterol of 240 mg/dL or higher; and 27.8% have high levels of low-density lipoprotein cholesterol (130 mg/dL or higher).

Diabetes

In 2019, 87,647 U.S. deaths were attributed to diabetes; data show that 9.8 million U.S. adults have undiagnosed diabetes, 28.2 million have diagnosed diabetes, and 113.6 million have prediabetes.

Hypertension

A total of 121.5 million (47.3%) U.S. adults have hypertension, based on 2015–2018 data. In 2019, 102,072 U.S. deaths were primarily attributable to hypertension.

This statistical update was prepared by a volunteer writing group on behalf of the American Heart Association Council on Epidemiology and Prevention Statistics Committee and Stroke Statistics Subcommittee. Disclosures for the writing committee are listed with the original article.



A version of this article first appeared on Medscape.com.

The American Heart Association (AHA) draws attention to the important bidirectional link between cardiovascular health and brain health in its annual statistical update on heart disease and stroke.

“For several years now, the AHA and the scientific community have increasingly recognized the connections between cardiovascular health and brain health, so it was time for us to cement this into its own chapter, which we highlight as the brain health chapter,” Connie W. Tsao, MD, MPH, chair of the statistical update writing group, with Harvard Medical School, Boston, said in an AHA podcast.

“The global rate of brain disease is quickly outpacing heart disease,” Mitchell S. V. Elkind, MD, immediate past president of the AHA, added in a news release.

“The rate of deaths from Alzheimer’s disease and other dementias rose more than twice as much in the past decade compared to the rate of deaths from heart disease, and that is something we must address,” said Dr. Elkind, with Columbia University Vagelos College of Physicians and Surgeons in New York.

“It’s becoming more evident that reducing vascular disease risk factors can make a real difference in helping people live longer, healthier lives, free of heart disease and brain disease,” Dr. Elkind added.

The AHA’s Heart Disease and Stroke Statistics – 2022 Update was published online January 26 in Circulation).

The report highlights some of the research connecting heart and brain health, including the following:

• A meta-analysis of 139 studies showed that people with midlife hypertension were five times more likely to experience impairment on global cognition and about twice as likely to experience reduced executive function, dementia, and Alzheimer’s disease.
• A meta-analysis of four longitudinal studies found that the risk for dementia associated with heart failure was increased nearly twofold.
• In the large prospective Atherosclerosis Risk in Communities (ARIC) Neurocognitive Study, atrial fibrillation was associated with greater cognitive decline and dementia over 20 years.
• A meta-analysis of 10 prospective studies (including 24,801 participants) showed that coronary heart disease (CHD) was associated with a 40% increased risk of poor cognitive outcomes, including dementia, cognitive impairment, or cognitive decline.

“This new chapter on brain health was a critical one to add,” Dr. Tsao said in the news release.

“The data we’ve collected brings to light the strong correlations between heart health and brain health and makes it an easy story to tell -- what’s good for the heart is good for the brain,” Dr. Tsao added.

Along with the new chapter on brain health, the 2022 statistical update provides the latest statistics and heart disease and stroke. Among the highlights:

• Cardiovascular disease (CVD) remains the leading cause of death worldwide. In the United States in 2019, CVD, listed as the underlying cause of death, accounted for 874,613 deaths, about 2,396 deaths each day. On average, someone dies of CVD every 36 seconds.
• CVD claims more lives each year in the United States than all forms of cancer and chronic lower respiratory disease combined.
• In 2019, CHD was the leading cause (41.3%) of deaths attributable to CVD, followed by other CVD (17.3%), stroke (17.2%), hypertension (11.7%), heart failure (9.9%), and diseases of the arteries (2.8%).
• In 2019, stroke accounted for roughly 1 in every 19 deaths in the United States. On average, someone in the United States has a stroke every 40 seconds and someone dies of stroke every 3 minutes 30 seconds. When considered separately from other CVD, stroke ranks number five among all causes of death in the United States.

While the annual statistics update aims to be a contemporary update of annual heart disease and stroke statistics over the past year, it also examines trends over time, Dr. Tsao explains in the podcast.

“One noteworthy point is that we saw a decline in the rate of cardiovascular mortality over the past three decades or so until about 2010. But over the past decade now, we’re also seeing a rise in these numbers,” she said.

This could be due to rising rates of obesity, diabetes, and poor hypertension control, as well as other lifestyle behaviors, Tsao said.
 

Key risk factor data

Each year, the statistical update gauges the cardiovascular health of Americans by tracking seven key health factors and behaviors that increase risk for heart disease and stroke. Below is a snapshot of the latest risk factor data.

Smoking

In 2019, smoking was the leading risk factor for years of life lost to premature death and the third leading risk factor for years of life lived with disability or injury.

According to the 2020 surgeon general’s report on smoking cessation, more than 480,000 Americans die as a result of cigarette smoking, and more than 41,000 die of secondhand smoke exposure each year (roughly 1 in 5 deaths annually).

One in 7 adults are current smokers, 1 in 6 female adults are current smokers, and 1 in 5 high school students use e-cigarettes.
 

Physical inactivity

In 2018, 25.4% of U.S. adults did not engage in leisure-time physical activity, and only 24.0% met the 2018 Physical Activity Guidelines for Americans for both aerobic and muscle strengthening.

Among U.S. high school students in 2019, only 44.1% were physically active for 60 minutes or more on at least 5 days of the week.
 

Nutrition

While there is some evidence that Americans are improving their diet, fewer than 10% of U.S. adults met guidelines for whole grain, whole fruit, and nonstarchy vegetable consumption each day in 2017–2018.

Overweight/obesity

The prevalence of obesity among adults increased from 1999–2000 through 2017–2018 from 30.5% to 42.4%. Overall prevalence of obesity and severe obesity in U.S. youth 2 to 19 years of age increased from 13.9% to 19.3% and 2.6% to 6.1% between 1999–2000 and 2017–2018.

Cholesterol

Close to 94 million (38.1%) U.S. adults have total cholesterol of 200 mg/dL or higher, according to 2015–2018 data; about 28.0 million (11.5%) have total cholesterol of 240 mg/dL or higher; and 27.8% have high levels of low-density lipoprotein cholesterol (130 mg/dL or higher).

Diabetes

In 2019, 87,647 U.S. deaths were attributed to diabetes; data show that 9.8 million U.S. adults have undiagnosed diabetes, 28.2 million have diagnosed diabetes, and 113.6 million have prediabetes.

Hypertension

A total of 121.5 million (47.3%) U.S. adults have hypertension, based on 2015–2018 data. In 2019, 102,072 U.S. deaths were primarily attributable to hypertension.

This statistical update was prepared by a volunteer writing group on behalf of the American Heart Association Council on Epidemiology and Prevention Statistics Committee and Stroke Statistics Subcommittee. Disclosures for the writing committee are listed with the original article.



A version of this article first appeared on Medscape.com.

It all started with genetic data. A gene here, a gene there. Eventually the story became clearer: If scientists are to one day find a cure for Alzheimer’s disease, they should look to the immune system.

Over the past couple decades, researchers have identified numerous genes involved in various immune system functions that may also contribute to Alzheimer’s disease. Some of the prime suspects are genes that control microglia, now the focus of intense research in developing new Alzheimer’s drugs.

Microglia are amoeba-like cells that scour the brain for injuries and invaders. They help clear dead or impaired brain cells and literally gobble up invading microbes. Without them, we’d be in trouble.

In a normal brain, a protein called beta-amyloid is cleared away through our lymphatic system by microglia as molecular junk. But sometimes it builds up. Certain gene mutations are one culprit in this toxic accumulation. Traumatic brain injury is another, and, perhaps, impaired microglial function.

One thing everyone agrees on is that in people with Alzheimer’s disease, too much amyloid accumulates between their brain cells and in the vessels that supply the brain with blood. Once amyloid begins to clog networks of neurons, it triggers the accumulation of another protein, called tau, inside of these brain cells. The presence of tau sends microglia and other immune mechanisms into overdrive, resulting in the inflammatory immune response that many experts believe ultimately saps brain vitality in Alzheimer’s disease.
 

The gene scene

To date, nearly a dozen genes involved in immune and microglial function have been tied to Alzheimer’s disease. The first was CD33, identified in 2008.

“When we got the results, I literally ran to my colleague’s office next door and said, you gotta see this!” said Harvard neuroscientist Rudolph Tanzi. Dr. Tanzi, who goes by Rudy, led the CD33 research. The discovery was quickly named a top medical breakthrough of 2008 by Time magazine.

“We were laughing because what they didn’t know is we had no idea what this gene did,” he joked. But over time, research by Dr. Tanzi and his group revealed that CD33 is a kind of microglial on-off switch, activating the cells as part of an inflammatory pathway.

“We kind of got it all going when it came to the genetics,” he said.

Microglia normally recognize molecular patterns associated with microbes and cellular damage as unwanted. This is how they know to take action – to devour unfamiliar pathogens and dead tissue. Dr. Tanzi believes microglia sense any sign of brain damage as an infection, which causes them to become hyperactive.

Much of our modern human immune system, he explained, evolved many hundreds of thousands of years ago. Our lifespans at the time were far shorter than they are today, and the majority of people didn’t live long enough to develop dementia or the withered brain cells that come with it. So our immune system, he said, assumes any faulty brain tissue is due to a microbe, not dementia. Microglia react aggressively, clearing the area to prevent the spread of infection.

“They say, ‘We better wipe out this part of the brain that’s infected, even if it’s not.’ They don’t know,” quipped Dr. Tanzi. “That’s what causes neuroinflammation. And CD33 turns this response on. The microglia become killers, not just janitors.”
 

A brake on overactive microglia

If CD33 is the yin, a gene called TREM2 is the yang. Discovered a few years after CD33, TREM2 reins in microglial activation, returning them to their role as cellular housekeepers.

Neurologist David Holtzman, MD, of Washington University in St. Louis, who studies TREM2, agrees that wherever you find amyloid, tau, or dead brain cells, there are microglia raring to go and ready to scavenge.

“I think at first a lot of people thought these cells were reacting to Alzheimer’s pathology, and not necessarily a cause of the disease,” he said.

It was the discovery of TREM2 on the heels of CD33 that really shifted the thinking, in part because it produces a protein that in the brain is only found in microglia. “Many of us [in the field] immediately said, ‘Look, there’s now a risk factor that is only expressed in microglia. It must be that innate immune cells are important in some way in the pathogenesis of the disease,’ “ he added.

Dr. Holtzman sees microglial activation in impending dementia as a double-edged sword. In the beginning, microglia clear unwanted amyloid to maintain brain health. But once accumulated amyloid and tau have done enough damage, the neuroinflammation that comes with microglial activation does more harm than good. Neurons die en masse and dementia sets in.

But not all researchers are convinced.

Serge Revist, PhD, is a professor in the department of molecular medicine at the Laval University Medical School in Quebec. Based on his lab’s research, he believes that while impaired immune activity is involved in Alzheimer’s disease, it is not the root cause. “I don’t think it is the immune cells that do the damage, I still think it is the beta-amyloid itself,” he said, “In my lab, in mouse studies, we’ve never found that immune cells were directly responsible for killing neurons.”

He does believe that in some patients with Alzheimer’s disease, microglia may not be able to handle the excess amyloid that accumulates in the disease and that developing treatments that improve the ability of microglia and the immune system to clear the protein could be effective.
 

Microglial medicines

The biological cascade leading to Alzheimer’s disease is a tangled one. Gene variants influencing the accumulation and clearance of amyloid are likely a major contributor. But immune activity caused by early life infection might also be involved, at least in some cases. This infectious theory of Alzheimer’s disease was first proposed by Dr. Tanzi’s now-deceased colleague Robert Moir, PhD. Dr. Tanzi’s group even has evidence that amyloid itself is antimicrobial and evolved to protect us from pathogens, only to become a problem when overactive and aggregated.

And the same goes for microglia, cells whose over-ambition might cause much of the brain degeneration seen in Alzheimer’s disease.

In theory, if a treatment could decrease CD33 activity or increase that of TREM2, doctors might one day may be able to slow or even stop the progression of dementia. Instead of going after amyloid itself – the mechanism behind so many failed investigational Alzheimer’s drugs – a therapy that quells the immune response to amyloid might be the answer in treating dementia.

“There are a number of scientists and companies trying to figure out how to influence genes like TREM2 and CD33 and to both decrease amyloid and act on the downstream consequences of the protein,” said Dr. Holtzman. “All of this is to say that somewhere in the biology that causes Alzheimer’s disease, the immune system is involved.”

It seems that in many cases, the most common form of a dementia might be due to a well-intentioned immune cell going rogue. “I think you’d hear this from basically any researcher worth their salt,” said Dr. Tanzi. “I feel strongly that without microglial activation, you will not get Alzheimer’s disease.”

A version of this article first appeared on Medscape.com.

It all started with genetic data. A gene here, a gene there. Eventually the story became clearer: If scientists are to one day find a cure for Alzheimer’s disease, they should look to the immune system.

Over the past couple decades, researchers have identified numerous genes involved in various immune system functions that may also contribute to Alzheimer’s disease. Some of the prime suspects are genes that control microglia, now the focus of intense research in developing new Alzheimer’s drugs.

Microglia are amoeba-like cells that scour the brain for injuries and invaders. They help clear dead or impaired brain cells and literally gobble up invading microbes. Without them, we’d be in trouble.

In a normal brain, a protein called beta-amyloid is cleared away through our lymphatic system by microglia as molecular junk. But sometimes it builds up. Certain gene mutations are one culprit in this toxic accumulation. Traumatic brain injury is another, and, perhaps, impaired microglial function.

One thing everyone agrees on is that in people with Alzheimer’s disease, too much amyloid accumulates between their brain cells and in the vessels that supply the brain with blood. Once amyloid begins to clog networks of neurons, it triggers the accumulation of another protein, called tau, inside of these brain cells. The presence of tau sends microglia and other immune mechanisms into overdrive, resulting in the inflammatory immune response that many experts believe ultimately saps brain vitality in Alzheimer’s disease.
 

The gene scene

To date, nearly a dozen genes involved in immune and microglial function have been tied to Alzheimer’s disease. The first was CD33, identified in 2008.

“When we got the results, I literally ran to my colleague’s office next door and said, you gotta see this!” said Harvard neuroscientist Rudolph Tanzi. Dr. Tanzi, who goes by Rudy, led the CD33 research. The discovery was quickly named a top medical breakthrough of 2008 by Time magazine.

“We were laughing because what they didn’t know is we had no idea what this gene did,” he joked. But over time, research by Dr. Tanzi and his group revealed that CD33 is a kind of microglial on-off switch, activating the cells as part of an inflammatory pathway.

“We kind of got it all going when it came to the genetics,” he said.

Microglia normally recognize molecular patterns associated with microbes and cellular damage as unwanted. This is how they know to take action – to devour unfamiliar pathogens and dead tissue. Dr. Tanzi believes microglia sense any sign of brain damage as an infection, which causes them to become hyperactive.

Much of our modern human immune system, he explained, evolved many hundreds of thousands of years ago. Our lifespans at the time were far shorter than they are today, and the majority of people didn’t live long enough to develop dementia or the withered brain cells that come with it. So our immune system, he said, assumes any faulty brain tissue is due to a microbe, not dementia. Microglia react aggressively, clearing the area to prevent the spread of infection.

“They say, ‘We better wipe out this part of the brain that’s infected, even if it’s not.’ They don’t know,” quipped Dr. Tanzi. “That’s what causes neuroinflammation. And CD33 turns this response on. The microglia become killers, not just janitors.”
 

A brake on overactive microglia

If CD33 is the yin, a gene called TREM2 is the yang. Discovered a few years after CD33, TREM2 reins in microglial activation, returning them to their role as cellular housekeepers.

Neurologist David Holtzman, MD, of Washington University in St. Louis, who studies TREM2, agrees that wherever you find amyloid, tau, or dead brain cells, there are microglia raring to go and ready to scavenge.

“I think at first a lot of people thought these cells were reacting to Alzheimer’s pathology, and not necessarily a cause of the disease,” he said.

It was the discovery of TREM2 on the heels of CD33 that really shifted the thinking, in part because it produces a protein that in the brain is only found in microglia. “Many of us [in the field] immediately said, ‘Look, there’s now a risk factor that is only expressed in microglia. It must be that innate immune cells are important in some way in the pathogenesis of the disease,’ “ he added.

Dr. Holtzman sees microglial activation in impending dementia as a double-edged sword. In the beginning, microglia clear unwanted amyloid to maintain brain health. But once accumulated amyloid and tau have done enough damage, the neuroinflammation that comes with microglial activation does more harm than good. Neurons die en masse and dementia sets in.

But not all researchers are convinced.

Serge Revist, PhD, is a professor in the department of molecular medicine at the Laval University Medical School in Quebec. Based on his lab’s research, he believes that while impaired immune activity is involved in Alzheimer’s disease, it is not the root cause. “I don’t think it is the immune cells that do the damage, I still think it is the beta-amyloid itself,” he said, “In my lab, in mouse studies, we’ve never found that immune cells were directly responsible for killing neurons.”

He does believe that in some patients with Alzheimer’s disease, microglia may not be able to handle the excess amyloid that accumulates in the disease and that developing treatments that improve the ability of microglia and the immune system to clear the protein could be effective.
 

Microglial medicines

The biological cascade leading to Alzheimer’s disease is a tangled one. Gene variants influencing the accumulation and clearance of amyloid are likely a major contributor. But immune activity caused by early life infection might also be involved, at least in some cases. This infectious theory of Alzheimer’s disease was first proposed by Dr. Tanzi’s now-deceased colleague Robert Moir, PhD. Dr. Tanzi’s group even has evidence that amyloid itself is antimicrobial and evolved to protect us from pathogens, only to become a problem when overactive and aggregated.

And the same goes for microglia, cells whose over-ambition might cause much of the brain degeneration seen in Alzheimer’s disease.

In theory, if a treatment could decrease CD33 activity or increase that of TREM2, doctors might one day may be able to slow or even stop the progression of dementia. Instead of going after amyloid itself – the mechanism behind so many failed investigational Alzheimer’s drugs – a therapy that quells the immune response to amyloid might be the answer in treating dementia.

“There are a number of scientists and companies trying to figure out how to influence genes like TREM2 and CD33 and to both decrease amyloid and act on the downstream consequences of the protein,” said Dr. Holtzman. “All of this is to say that somewhere in the biology that causes Alzheimer’s disease, the immune system is involved.”

It seems that in many cases, the most common form of a dementia might be due to a well-intentioned immune cell going rogue. “I think you’d hear this from basically any researcher worth their salt,” said Dr. Tanzi. “I feel strongly that without microglial activation, you will not get Alzheimer’s disease.”

A version of this article first appeared on Medscape.com.

It all started with genetic data. A gene here, a gene there. Eventually the story became clearer: If scientists are to one day find a cure for Alzheimer’s disease, they should look to the immune system.

Over the past couple decades, researchers have identified numerous genes involved in various immune system functions that may also contribute to Alzheimer’s disease. Some of the prime suspects are genes that control microglia, now the focus of intense research in developing new Alzheimer’s drugs.

Microglia are amoeba-like cells that scour the brain for injuries and invaders. They help clear dead or impaired brain cells and literally gobble up invading microbes. Without them, we’d be in trouble.

In a normal brain, a protein called beta-amyloid is cleared away through our lymphatic system by microglia as molecular junk. But sometimes it builds up. Certain gene mutations are one culprit in this toxic accumulation. Traumatic brain injury is another, and, perhaps, impaired microglial function.

One thing everyone agrees on is that in people with Alzheimer’s disease, too much amyloid accumulates between their brain cells and in the vessels that supply the brain with blood. Once amyloid begins to clog networks of neurons, it triggers the accumulation of another protein, called tau, inside of these brain cells. The presence of tau sends microglia and other immune mechanisms into overdrive, resulting in the inflammatory immune response that many experts believe ultimately saps brain vitality in Alzheimer’s disease.
 

The gene scene

To date, nearly a dozen genes involved in immune and microglial function have been tied to Alzheimer’s disease. The first was CD33, identified in 2008.

“When we got the results, I literally ran to my colleague’s office next door and said, you gotta see this!” said Harvard neuroscientist Rudolph Tanzi. Dr. Tanzi, who goes by Rudy, led the CD33 research. The discovery was quickly named a top medical breakthrough of 2008 by Time magazine.

“We were laughing because what they didn’t know is we had no idea what this gene did,” he joked. But over time, research by Dr. Tanzi and his group revealed that CD33 is a kind of microglial on-off switch, activating the cells as part of an inflammatory pathway.

“We kind of got it all going when it came to the genetics,” he said.

Microglia normally recognize molecular patterns associated with microbes and cellular damage as unwanted. This is how they know to take action – to devour unfamiliar pathogens and dead tissue. Dr. Tanzi believes microglia sense any sign of brain damage as an infection, which causes them to become hyperactive.

Much of our modern human immune system, he explained, evolved many hundreds of thousands of years ago. Our lifespans at the time were far shorter than they are today, and the majority of people didn’t live long enough to develop dementia or the withered brain cells that come with it. So our immune system, he said, assumes any faulty brain tissue is due to a microbe, not dementia. Microglia react aggressively, clearing the area to prevent the spread of infection.

“They say, ‘We better wipe out this part of the brain that’s infected, even if it’s not.’ They don’t know,” quipped Dr. Tanzi. “That’s what causes neuroinflammation. And CD33 turns this response on. The microglia become killers, not just janitors.”
 

A brake on overactive microglia

If CD33 is the yin, a gene called TREM2 is the yang. Discovered a few years after CD33, TREM2 reins in microglial activation, returning them to their role as cellular housekeepers.

Neurologist David Holtzman, MD, of Washington University in St. Louis, who studies TREM2, agrees that wherever you find amyloid, tau, or dead brain cells, there are microglia raring to go and ready to scavenge.

“I think at first a lot of people thought these cells were reacting to Alzheimer’s pathology, and not necessarily a cause of the disease,” he said.

It was the discovery of TREM2 on the heels of CD33 that really shifted the thinking, in part because it produces a protein that in the brain is only found in microglia. “Many of us [in the field] immediately said, ‘Look, there’s now a risk factor that is only expressed in microglia. It must be that innate immune cells are important in some way in the pathogenesis of the disease,’ “ he added.

Dr. Holtzman sees microglial activation in impending dementia as a double-edged sword. In the beginning, microglia clear unwanted amyloid to maintain brain health. But once accumulated amyloid and tau have done enough damage, the neuroinflammation that comes with microglial activation does more harm than good. Neurons die en masse and dementia sets in.

But not all researchers are convinced.

Serge Revist, PhD, is a professor in the department of molecular medicine at the Laval University Medical School in Quebec. Based on his lab’s research, he believes that while impaired immune activity is involved in Alzheimer’s disease, it is not the root cause. “I don’t think it is the immune cells that do the damage, I still think it is the beta-amyloid itself,” he said, “In my lab, in mouse studies, we’ve never found that immune cells were directly responsible for killing neurons.”

He does believe that in some patients with Alzheimer’s disease, microglia may not be able to handle the excess amyloid that accumulates in the disease and that developing treatments that improve the ability of microglia and the immune system to clear the protein could be effective.
 

Microglial medicines

The biological cascade leading to Alzheimer’s disease is a tangled one. Gene variants influencing the accumulation and clearance of amyloid are likely a major contributor. But immune activity caused by early life infection might also be involved, at least in some cases. This infectious theory of Alzheimer’s disease was first proposed by Dr. Tanzi’s now-deceased colleague Robert Moir, PhD. Dr. Tanzi’s group even has evidence that amyloid itself is antimicrobial and evolved to protect us from pathogens, only to become a problem when overactive and aggregated.

And the same goes for microglia, cells whose over-ambition might cause much of the brain degeneration seen in Alzheimer’s disease.

In theory, if a treatment could decrease CD33 activity or increase that of TREM2, doctors might one day may be able to slow or even stop the progression of dementia. Instead of going after amyloid itself – the mechanism behind so many failed investigational Alzheimer’s drugs – a therapy that quells the immune response to amyloid might be the answer in treating dementia.

“There are a number of scientists and companies trying to figure out how to influence genes like TREM2 and CD33 and to both decrease amyloid and act on the downstream consequences of the protein,” said Dr. Holtzman. “All of this is to say that somewhere in the biology that causes Alzheimer’s disease, the immune system is involved.”

It seems that in many cases, the most common form of a dementia might be due to a well-intentioned immune cell going rogue. “I think you’d hear this from basically any researcher worth their salt,” said Dr. Tanzi. “I feel strongly that without microglial activation, you will not get Alzheimer’s disease.”

A version of this article first appeared on Medscape.com.

Subclinical changes in cardiac structure and diastolic function in early adulthood may serve as risk markers for cognitive decline in midlife, new research suggests.

Cardiovascular disease risk factors such as high blood pressure, high cholesterol, and diabetes have been associated with an increased risk for cognitive impairment, but much less is known about heart structure and function and the risks for cognition.

“We showed for the first time that, even before the occurrence of cardiovascular disease, people with abnormalities in cardiac structure and function as early as in young adulthood have lower midlife cognition,” investigators Laure Rouch, PharmD, PhD, and Kristine Yaffe, MD, both with the department of psychiatry, University of California, San Francisco, said in a joint email.

“This study reminds us that heart health is key to brain health and that the overlap and interplay between the two is not limited to patients with end-stage heart disease,” Dr. Rouch and Dr. Yaffe said.

The findings were published online Jan. 26, 2022, in Neurology.
 

Heart/brain connection

The analysis included 2,653 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study.

Echocardiograms were obtained at year 5, 25, and 30 study visits – at mean ages of 30, 50, and 55 years, respectively. At year 30, participants underwent a standard battery of tests measuring global cognition, processing speed, executive function, delayed verbal memory, and verbal fluency.

Over 25 years, there was an average increase in left ventricular mass of 0.27 g/m2 per year – from a mean of 80.5 g/m² in year 5 to 86.0 g/m² in year 30.

Left atrial volume increased by an average of 0.42 mL/m2 per year, from 16 mL/m² in year 5 to 26 mL/m² in year 30.

Left ventricular ejection fraction (LVEF) decreased by 0.11% per year, from 63.3% in year 5 to 59.7% in year 30.

After adjustment for demographics and education, an increase in left ventricular mass of at least 1 standard deviation over 25 years was associated with lower cognition on most tests (P ≤ .02).

An increase in left atrial volume over the study period was associated with lower global cognition (P = .04), whereas a decrease in LVEF was not associated with cognition. Further adjustment for cardiovascular risk factors yielded similar results.

“A more effective collaboration is needed between cardiologists and neurologists to promote healthy brain aging,” Dr. Rouch and Dr. Yaffe said.

“Echocardiography is a widely available, relatively inexpensive, and noninvasive imaging method that could be integrated into a risk assessment for cognitive impairment,” they added.

Looking ahead, the investigators noted there is a need for further research to determine whether interventions to improve cardiac structure and diastolic function could also benefit brain health.

They should also investigate the role of arterial stiffness and cerebral small vessel disease in the relationship between cardiac structure, function, and cognition, the researchers added.
 

First structural biomarker

Commenting on the study, Shaheen E. Lakhan, MD, PhD, a neurologist in Newton, Mass., said the study is important because, “thus far, the connections have really been physiological parameters,” such as blood pressure and cognitive health.

“This is really strong evidence of a structural cardiac biomarker that can be measured before and independent of changes in physiology or diseased state,” said Dr. Lakhan, who was not involved with the research.

As more and more interventions are being introduced for addressing disorders of cognition, “this potential structural finding may serve as a solid biomarker to determine” what lifestyle or drug therapy should be taken, he added.

Also weighing in on the findings, Pierre Fayad, MD, professor in the department of neurological sciences and director of the Nebraska Stroke Center, University of Nebraska Medical Center, Omaha, said CARDIA is “an important study” providing “precious data.”

The reported changes in cardiac structure and function “precede the clinical symptomatology, as the follow-up stops before they enter into later adulthood, where the risk of clinical events dramatically rises. Meaning these patients still have not had stroke, congestive heart failure, heart attack or dementia, but some of them could be on that trajectory later in their life,” Dr. Fayad told this news organization.

Documenting such changes over time is “valuable to give an insight into what leads us to such progression,” he noted.

How reliably predictive the findings are for eventual clinical cognitive impairment “will need to be confirmed and verified” in future studies, he added.

“If verified, it could be helpful to provide interventions to those with the left atrial volume enlargement marker and see their effectiveness at preventing eventual clinical cognitive impairment,” said Dr. Fayad.

The CARDIA study is supported by the National Heart, Lung, and Blood Institute in collaboration with the University of Alabama at Birmingham, Northwestern University, the University of Minnesota, and the Kaiser Foundation Research Institute. Rouch, Lakhan, and Dr. Fayad have disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Subclinical changes in cardiac structure and diastolic function in early adulthood may serve as risk markers for cognitive decline in midlife, new research suggests.

Cardiovascular disease risk factors such as high blood pressure, high cholesterol, and diabetes have been associated with an increased risk for cognitive impairment, but much less is known about heart structure and function and the risks for cognition.

“We showed for the first time that, even before the occurrence of cardiovascular disease, people with abnormalities in cardiac structure and function as early as in young adulthood have lower midlife cognition,” investigators Laure Rouch, PharmD, PhD, and Kristine Yaffe, MD, both with the department of psychiatry, University of California, San Francisco, said in a joint email.

“This study reminds us that heart health is key to brain health and that the overlap and interplay between the two is not limited to patients with end-stage heart disease,” Dr. Rouch and Dr. Yaffe said.

The findings were published online Jan. 26, 2022, in Neurology.
 

Heart/brain connection

The analysis included 2,653 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study.

Echocardiograms were obtained at year 5, 25, and 30 study visits – at mean ages of 30, 50, and 55 years, respectively. At year 30, participants underwent a standard battery of tests measuring global cognition, processing speed, executive function, delayed verbal memory, and verbal fluency.

Over 25 years, there was an average increase in left ventricular mass of 0.27 g/m2 per year – from a mean of 80.5 g/m² in year 5 to 86.0 g/m² in year 30.

Left atrial volume increased by an average of 0.42 mL/m2 per year, from 16 mL/m² in year 5 to 26 mL/m² in year 30.

Left ventricular ejection fraction (LVEF) decreased by 0.11% per year, from 63.3% in year 5 to 59.7% in year 30.

After adjustment for demographics and education, an increase in left ventricular mass of at least 1 standard deviation over 25 years was associated with lower cognition on most tests (P ≤ .02).

An increase in left atrial volume over the study period was associated with lower global cognition (P = .04), whereas a decrease in LVEF was not associated with cognition. Further adjustment for cardiovascular risk factors yielded similar results.

“A more effective collaboration is needed between cardiologists and neurologists to promote healthy brain aging,” Dr. Rouch and Dr. Yaffe said.

“Echocardiography is a widely available, relatively inexpensive, and noninvasive imaging method that could be integrated into a risk assessment for cognitive impairment,” they added.

Looking ahead, the investigators noted there is a need for further research to determine whether interventions to improve cardiac structure and diastolic function could also benefit brain health.

They should also investigate the role of arterial stiffness and cerebral small vessel disease in the relationship between cardiac structure, function, and cognition, the researchers added.
 

First structural biomarker

Commenting on the study, Shaheen E. Lakhan, MD, PhD, a neurologist in Newton, Mass., said the study is important because, “thus far, the connections have really been physiological parameters,” such as blood pressure and cognitive health.

“This is really strong evidence of a structural cardiac biomarker that can be measured before and independent of changes in physiology or diseased state,” said Dr. Lakhan, who was not involved with the research.

As more and more interventions are being introduced for addressing disorders of cognition, “this potential structural finding may serve as a solid biomarker to determine” what lifestyle or drug therapy should be taken, he added.

Also weighing in on the findings, Pierre Fayad, MD, professor in the department of neurological sciences and director of the Nebraska Stroke Center, University of Nebraska Medical Center, Omaha, said CARDIA is “an important study” providing “precious data.”

The reported changes in cardiac structure and function “precede the clinical symptomatology, as the follow-up stops before they enter into later adulthood, where the risk of clinical events dramatically rises. Meaning these patients still have not had stroke, congestive heart failure, heart attack or dementia, but some of them could be on that trajectory later in their life,” Dr. Fayad told this news organization.

Documenting such changes over time is “valuable to give an insight into what leads us to such progression,” he noted.

How reliably predictive the findings are for eventual clinical cognitive impairment “will need to be confirmed and verified” in future studies, he added.

“If verified, it could be helpful to provide interventions to those with the left atrial volume enlargement marker and see their effectiveness at preventing eventual clinical cognitive impairment,” said Dr. Fayad.

The CARDIA study is supported by the National Heart, Lung, and Blood Institute in collaboration with the University of Alabama at Birmingham, Northwestern University, the University of Minnesota, and the Kaiser Foundation Research Institute. Rouch, Lakhan, and Dr. Fayad have disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Subclinical changes in cardiac structure and diastolic function in early adulthood may serve as risk markers for cognitive decline in midlife, new research suggests.

Cardiovascular disease risk factors such as high blood pressure, high cholesterol, and diabetes have been associated with an increased risk for cognitive impairment, but much less is known about heart structure and function and the risks for cognition.

“We showed for the first time that, even before the occurrence of cardiovascular disease, people with abnormalities in cardiac structure and function as early as in young adulthood have lower midlife cognition,” investigators Laure Rouch, PharmD, PhD, and Kristine Yaffe, MD, both with the department of psychiatry, University of California, San Francisco, said in a joint email.

“This study reminds us that heart health is key to brain health and that the overlap and interplay between the two is not limited to patients with end-stage heart disease,” Dr. Rouch and Dr. Yaffe said.

The findings were published online Jan. 26, 2022, in Neurology.
 

Heart/brain connection

The analysis included 2,653 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study.

Echocardiograms were obtained at year 5, 25, and 30 study visits – at mean ages of 30, 50, and 55 years, respectively. At year 30, participants underwent a standard battery of tests measuring global cognition, processing speed, executive function, delayed verbal memory, and verbal fluency.

Over 25 years, there was an average increase in left ventricular mass of 0.27 g/m2 per year – from a mean of 80.5 g/m² in year 5 to 86.0 g/m² in year 30.

Left atrial volume increased by an average of 0.42 mL/m2 per year, from 16 mL/m² in year 5 to 26 mL/m² in year 30.

Left ventricular ejection fraction (LVEF) decreased by 0.11% per year, from 63.3% in year 5 to 59.7% in year 30.

After adjustment for demographics and education, an increase in left ventricular mass of at least 1 standard deviation over 25 years was associated with lower cognition on most tests (P ≤ .02).

An increase in left atrial volume over the study period was associated with lower global cognition (P = .04), whereas a decrease in LVEF was not associated with cognition. Further adjustment for cardiovascular risk factors yielded similar results.

“A more effective collaboration is needed between cardiologists and neurologists to promote healthy brain aging,” Dr. Rouch and Dr. Yaffe said.

“Echocardiography is a widely available, relatively inexpensive, and noninvasive imaging method that could be integrated into a risk assessment for cognitive impairment,” they added.

Looking ahead, the investigators noted there is a need for further research to determine whether interventions to improve cardiac structure and diastolic function could also benefit brain health.

They should also investigate the role of arterial stiffness and cerebral small vessel disease in the relationship between cardiac structure, function, and cognition, the researchers added.
 

First structural biomarker

Commenting on the study, Shaheen E. Lakhan, MD, PhD, a neurologist in Newton, Mass., said the study is important because, “thus far, the connections have really been physiological parameters,” such as blood pressure and cognitive health.

“This is really strong evidence of a structural cardiac biomarker that can be measured before and independent of changes in physiology or diseased state,” said Dr. Lakhan, who was not involved with the research.

As more and more interventions are being introduced for addressing disorders of cognition, “this potential structural finding may serve as a solid biomarker to determine” what lifestyle or drug therapy should be taken, he added.

Also weighing in on the findings, Pierre Fayad, MD, professor in the department of neurological sciences and director of the Nebraska Stroke Center, University of Nebraska Medical Center, Omaha, said CARDIA is “an important study” providing “precious data.”

The reported changes in cardiac structure and function “precede the clinical symptomatology, as the follow-up stops before they enter into later adulthood, where the risk of clinical events dramatically rises. Meaning these patients still have not had stroke, congestive heart failure, heart attack or dementia, but some of them could be on that trajectory later in their life,” Dr. Fayad told this news organization.

Documenting such changes over time is “valuable to give an insight into what leads us to such progression,” he noted.

How reliably predictive the findings are for eventual clinical cognitive impairment “will need to be confirmed and verified” in future studies, he added.

“If verified, it could be helpful to provide interventions to those with the left atrial volume enlargement marker and see their effectiveness at preventing eventual clinical cognitive impairment,” said Dr. Fayad.

The CARDIA study is supported by the National Heart, Lung, and Blood Institute in collaboration with the University of Alabama at Birmingham, Northwestern University, the University of Minnesota, and the Kaiser Foundation Research Institute. Rouch, Lakhan, and Dr. Fayad have disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

The study covered in this summary was published in medRxiv.org as a preprint and has not yet been peer reviewed.

Key takeaways

• Measurement of the rate of cellular amyloid uptake and metabolic production of toxic amyloid species could be used as novel biomarkers for early and/or differential diagnosis of Alzheimer’s disease (AD).
• Estimated beta-amyloid (Aβ42) cellular uptake can be more than two times greater in AD patients compared to cognitively normal subjects. A less pronounced yet increased uptake rate was also observed in patients with late-onset mild cognitive impairment (MCI). This increased uptake may prove to be a key mechanism defining age-related AD progression.
• The increased cellular amyloid uptake in AD and LMCI may lead to quicker disease progression, but early-onset MCI may result from increased production of toxic amyloid metabolites.

Why this matters

• Additional biomarkers for AD could greatly aid diagnosis and course prediction, as they are currently limited to PET scan analysis of amyloid plaque deposits and concentration of Aβ42 in cerebrospinal fluid (CSF).
• Amyloid deposits found by PET have a positive correlation with AD diagnosis. In contrast, CSF-Aβ42 and AD diagnosis or cognitive decline are negatively correlated. Normal cognition (NC) is associated with higher CSF beta-amyloid levels, but previous research has not explained why CSF-Aβ42 levels can be equivalent in patients with NC but high amyloid load and patients with AD and low amyloid load.

Study design

• The authors of this retrospective study used anonymized data obtained from the Alzheimer’s’s Disease Neuroimaging Initiative (ADNI). ADNI’s goal has been to test whether serial MRI scans, PET scans, biomarkers, and clinical/neuropsychological assessment can be combined to measure the progression of MCI and AD.
• Study subjects had either an AD diagnosis or NC and were divided into two groups: low amyloid load and high amyloid load. The fraction of patients with an AD diagnosis was calculated as a function of CSF-Aβ42.
• Calculations and statistical comparisons were performed using Microsoft Excel and custom-written C++ programs.

Key results

• The lowest levels of CSF-Aβ42 correlated with the highest percentage of AD-diagnosed patients, estimated to be 27% in subjects with low amyloid deposit density and 65% in those with high deposit density.
• The relationship between CSF-Aβ42 levels and amyloid load can be described using a simple mathematical model: Amyloid concentration in the interstitial cells is equal to the synthesis rate divided by the density of amyloid deposits plus the sum of the rate of amyloid removal through the CSF and the cellular amyloid uptake rate.
• AD and late-onset MCI patients had a significantly higher amyloid removal rate compared to NC subjects.
• Early-onset MCI patients had Aβ42 turnover similar to that of NC subjects, pointing to a different underlying mechanism such as enzymatic disbalance.

Limitations

• The model used to explain amyloid exchange between the interstitial space and the CSF is oversimplified; the actual process is more complex.
• Synthesis and uptake rates of Aβ42 vary throughout areas of the brain. The model assumes a homogeneous distribution within the interstitial compartment.

Study disclosures

• Research reported in this publication was not supported by any external funding. Data collection and sharing for this project were funded by ADNI.

A version of this article first appeared on Medscape.com.

The study covered in this summary was published in medRxiv.org as a preprint and has not yet been peer reviewed.

Key takeaways

• Measurement of the rate of cellular amyloid uptake and metabolic production of toxic amyloid species could be used as novel biomarkers for early and/or differential diagnosis of Alzheimer’s disease (AD).
• Estimated beta-amyloid (Aβ42) cellular uptake can be more than two times greater in AD patients compared to cognitively normal subjects. A less pronounced yet increased uptake rate was also observed in patients with late-onset mild cognitive impairment (MCI). This increased uptake may prove to be a key mechanism defining age-related AD progression.
• The increased cellular amyloid uptake in AD and LMCI may lead to quicker disease progression, but early-onset MCI may result from increased production of toxic amyloid metabolites.

Why this matters

• Additional biomarkers for AD could greatly aid diagnosis and course prediction, as they are currently limited to PET scan analysis of amyloid plaque deposits and concentration of Aβ42 in cerebrospinal fluid (CSF).
• Amyloid deposits found by PET have a positive correlation with AD diagnosis. In contrast, CSF-Aβ42 and AD diagnosis or cognitive decline are negatively correlated. Normal cognition (NC) is associated with higher CSF beta-amyloid levels, but previous research has not explained why CSF-Aβ42 levels can be equivalent in patients with NC but high amyloid load and patients with AD and low amyloid load.

Study design

• The authors of this retrospective study used anonymized data obtained from the Alzheimer’s’s Disease Neuroimaging Initiative (ADNI). ADNI’s goal has been to test whether serial MRI scans, PET scans, biomarkers, and clinical/neuropsychological assessment can be combined to measure the progression of MCI and AD.
• Study subjects had either an AD diagnosis or NC and were divided into two groups: low amyloid load and high amyloid load. The fraction of patients with an AD diagnosis was calculated as a function of CSF-Aβ42.
• Calculations and statistical comparisons were performed using Microsoft Excel and custom-written C++ programs.

Key results

• The lowest levels of CSF-Aβ42 correlated with the highest percentage of AD-diagnosed patients, estimated to be 27% in subjects with low amyloid deposit density and 65% in those with high deposit density.
• The relationship between CSF-Aβ42 levels and amyloid load can be described using a simple mathematical model: Amyloid concentration in the interstitial cells is equal to the synthesis rate divided by the density of amyloid deposits plus the sum of the rate of amyloid removal through the CSF and the cellular amyloid uptake rate.
• AD and late-onset MCI patients had a significantly higher amyloid removal rate compared to NC subjects.
• Early-onset MCI patients had Aβ42 turnover similar to that of NC subjects, pointing to a different underlying mechanism such as enzymatic disbalance.

Limitations

• The model used to explain amyloid exchange between the interstitial space and the CSF is oversimplified; the actual process is more complex.
• Synthesis and uptake rates of Aβ42 vary throughout areas of the brain. The model assumes a homogeneous distribution within the interstitial compartment.

Study disclosures

• Research reported in this publication was not supported by any external funding. Data collection and sharing for this project were funded by ADNI.

A version of this article first appeared on Medscape.com.

The study covered in this summary was published in medRxiv.org as a preprint and has not yet been peer reviewed.

Key takeaways

• Measurement of the rate of cellular amyloid uptake and metabolic production of toxic amyloid species could be used as novel biomarkers for early and/or differential diagnosis of Alzheimer’s disease (AD).
• Estimated beta-amyloid (Aβ42) cellular uptake can be more than two times greater in AD patients compared to cognitively normal subjects. A less pronounced yet increased uptake rate was also observed in patients with late-onset mild cognitive impairment (MCI). This increased uptake may prove to be a key mechanism defining age-related AD progression.
• The increased cellular amyloid uptake in AD and LMCI may lead to quicker disease progression, but early-onset MCI may result from increased production of toxic amyloid metabolites.

Why this matters

• Additional biomarkers for AD could greatly aid diagnosis and course prediction, as they are currently limited to PET scan analysis of amyloid plaque deposits and concentration of Aβ42 in cerebrospinal fluid (CSF).
• Amyloid deposits found by PET have a positive correlation with AD diagnosis. In contrast, CSF-Aβ42 and AD diagnosis or cognitive decline are negatively correlated. Normal cognition (NC) is associated with higher CSF beta-amyloid levels, but previous research has not explained why CSF-Aβ42 levels can be equivalent in patients with NC but high amyloid load and patients with AD and low amyloid load.

Study design

• The authors of this retrospective study used anonymized data obtained from the Alzheimer’s’s Disease Neuroimaging Initiative (ADNI). ADNI’s goal has been to test whether serial MRI scans, PET scans, biomarkers, and clinical/neuropsychological assessment can be combined to measure the progression of MCI and AD.
• Study subjects had either an AD diagnosis or NC and were divided into two groups: low amyloid load and high amyloid load. The fraction of patients with an AD diagnosis was calculated as a function of CSF-Aβ42.
• Calculations and statistical comparisons were performed using Microsoft Excel and custom-written C++ programs.

Key results

• The lowest levels of CSF-Aβ42 correlated with the highest percentage of AD-diagnosed patients, estimated to be 27% in subjects with low amyloid deposit density and 65% in those with high deposit density.
• The relationship between CSF-Aβ42 levels and amyloid load can be described using a simple mathematical model: Amyloid concentration in the interstitial cells is equal to the synthesis rate divided by the density of amyloid deposits plus the sum of the rate of amyloid removal through the CSF and the cellular amyloid uptake rate.
• AD and late-onset MCI patients had a significantly higher amyloid removal rate compared to NC subjects.
• Early-onset MCI patients had Aβ42 turnover similar to that of NC subjects, pointing to a different underlying mechanism such as enzymatic disbalance.

Limitations

• The model used to explain amyloid exchange between the interstitial space and the CSF is oversimplified; the actual process is more complex.
• Synthesis and uptake rates of Aβ42 vary throughout areas of the brain. The model assumes a homogeneous distribution within the interstitial compartment.

Study disclosures

• Research reported in this publication was not supported by any external funding. Data collection and sharing for this project were funded by ADNI.

A version of this article first appeared on Medscape.com.

Medicare intends to limit coverage of the controversial Alzheimer’s drug aducanumab (Aduhelm, Biogen) via a special program intended to help assess how well this exorbitantly expensive medication works, federal officials announced Jan. 11.

On Dec. 20, 2021, Biogen announced a plan to reduce the annual U.S. cost of the drug by 50% – from $56,000 to $28,200 – as Centers for Medicare & Medicaid Services officials were deciding on Medicare’s coverage policy for the medication.

In making its proposed coverage decision, the CMS announced it will pay for aducanumab, a monoclonal antibody, under its coverage-with-evidence-development (CED) mechanism. In making its decision, the CMS approached aducanumab as the first of a potential new class of monoclonal antibodies for the treatment of Alzheimer’s disease. Food and Drug Administration–approved drugs in this class would be covered for those with Medicare only if they are enrolled in qualifying clinical trials, the CMS said. The agency will accept public comments on this decision for 30 days.  

In a statement, CMS Administrator Chiquita Brooks-LaSure said the agency is “committed to providing the American public with a clear, trusted, evidence-based decision that is made only after a thorough analysis of public feedback on the benefits and risks of coverage for Medicare patients.”

As previously reported, the FDA approved aducanumab on June 7, 2021, via an accelerated approval process. The approval, which set off a firestorm of controversy that included resignations of three FDA Peripheral and Central Nervous System Drugs Advisory Committee panel members, was granted based on the medication’s ability to reduce beta-amyloid plaque.

Under the accelerated approval mechanism, Biogen still must deliver solid scientific proof that aducanumab has clinically significant disease-modifying effects. However, the final evidence won’t be in any time soon. In its approval letter, the FDA set a 2030 deadline for a final report on this research.

 

‘Unusual but appropriate’ step

The Medicare decision marks something of a shift in the agency’s approach to paying for medications. On a call with reporters, Tamara Syrek Jensen, JD, director of CMS’ Coverage and Analysis Group, admitted that the agency had taken an “unusual but appropriate” step in trying to set a national policy regarding payment for a drug.

On the same call, Lee Fleisher, MD, CMS’ chief medical officer, addressed the challenges presented by aducanumab, given the serious need for treatments for Alzheimer’s disease. “As a practicing physician, I cannot overemphasize the need to understand the risks and benefits of a given treatment in order to better inform patients and their families,” Dr. Fleisher said. “We do know based on some of the evidence that there may be potential promise with this treatment. That’s why it is critical for us to pursue additional scientific evidence.”

The coverage-with-evidence program will allow Medicare to aid in gathering data, while protecting patients, Dr. Fleisher noted.

“CMS is using its authority provided by Congress to determine if the drug is considered reasonable and necessary, meaning that the benefits of improvement of cognition outweigh the harms in the Medicare population,” Dr. Fleisher said.
 

Biogen disappointed

Cambridge, Mass.–based Biogen urged the CMS to reconsider its approach to payment for aducanumab. In a statement, the company said Medicare should cover “the class of amyloid-directed therapies with the populations studied in the respective clinical trials and guided by expert recommendations for appropriate use.

“We believe Alzheimer’s patients should have access consistent with other therapies with FDA accelerated approval,” Biogen said in the release.

In the company’s view, the CED approach will “significantly limit patient access to an FDA-approved treatment, especially for underserved patients as evidenced in other CED determinations.

“CEDs can take months to years to initiate, and hundreds of Alzheimer’s patients – the majority of whom are Medicare beneficiaries – are progressing each day from mild to moderate disease stages, where treatment may no longer be an option,” Biogen said.

Drug makers had been worried about CMS opting for CED even before the draft decision was unveiled.
 

Others weigh in

BIO, the trade group for biotechnology companies, urged the CMS to provide access to aducanumab without excess restrictions.

There already are concerns among drug makers about CMS efforts “to impose new coverage barriers – and, in particular, coverage with evidence development,” Crystal Kuntz, vice president of policy and research at BIO, and Andy Cosgrove, the organization’s senior director for policy and research, noted in a July 2021 comment about the aducanumab review.

Medicare should instead continue to provide access to medicines for indications that the FDA has approved, with additional flexibility for off-label indications of cancer drugs, they noted. “We believe this should continue to be the case, to ensure that vulnerable Medicare beneficiaries have necessary access to life-altering and lifesaving medications,” the BIO officials wrote.

However, the CMS also received many pleas from physicians asking the agency to limit use of aducanumab at least until there is evidence that it produces a significant clinical benefit.

In a press release, Howard Fillit, MD, cofounder and chief science officer of the Alzheimer’s Drug Discovery Foundation, applauded the decision, describing it as “the right call.

“This decision supports conducting additional clinical trials, which are needed to obtain further insights into the clinical efficacy and safety profile of this drug in real-world populations. This decision has implications for other drugs in this class in late-stage development. If these trials show more clear and robust clinical efficacy, then it is possible the FDA will give these amyloid monoclonal antibodies full approval, and Medicare would be likely to provide full payment,” he added.

A version of this article first appeared on Medscape.com.

Medicare intends to limit coverage of the controversial Alzheimer’s drug aducanumab (Aduhelm, Biogen) via a special program intended to help assess how well this exorbitantly expensive medication works, federal officials announced Jan. 11.

On Dec. 20, 2021, Biogen announced a plan to reduce the annual U.S. cost of the drug by 50% – from $56,000 to $28,200 – as Centers for Medicare & Medicaid Services officials were deciding on Medicare’s coverage policy for the medication.

In making its proposed coverage decision, the CMS announced it will pay for aducanumab, a monoclonal antibody, under its coverage-with-evidence-development (CED) mechanism. In making its decision, the CMS approached aducanumab as the first of a potential new class of monoclonal antibodies for the treatment of Alzheimer’s disease. Food and Drug Administration–approved drugs in this class would be covered for those with Medicare only if they are enrolled in qualifying clinical trials, the CMS said. The agency will accept public comments on this decision for 30 days.  

In a statement, CMS Administrator Chiquita Brooks-LaSure said the agency is “committed to providing the American public with a clear, trusted, evidence-based decision that is made only after a thorough analysis of public feedback on the benefits and risks of coverage for Medicare patients.”

As previously reported, the FDA approved aducanumab on June 7, 2021, via an accelerated approval process. The approval, which set off a firestorm of controversy that included resignations of three FDA Peripheral and Central Nervous System Drugs Advisory Committee panel members, was granted based on the medication’s ability to reduce beta-amyloid plaque.

Under the accelerated approval mechanism, Biogen still must deliver solid scientific proof that aducanumab has clinically significant disease-modifying effects. However, the final evidence won’t be in any time soon. In its approval letter, the FDA set a 2030 deadline for a final report on this research.

 

‘Unusual but appropriate’ step

The Medicare decision marks something of a shift in the agency’s approach to paying for medications. On a call with reporters, Tamara Syrek Jensen, JD, director of CMS’ Coverage and Analysis Group, admitted that the agency had taken an “unusual but appropriate” step in trying to set a national policy regarding payment for a drug.

On the same call, Lee Fleisher, MD, CMS’ chief medical officer, addressed the challenges presented by aducanumab, given the serious need for treatments for Alzheimer’s disease. “As a practicing physician, I cannot overemphasize the need to understand the risks and benefits of a given treatment in order to better inform patients and their families,” Dr. Fleisher said. “We do know based on some of the evidence that there may be potential promise with this treatment. That’s why it is critical for us to pursue additional scientific evidence.”

The coverage-with-evidence program will allow Medicare to aid in gathering data, while protecting patients, Dr. Fleisher noted.

“CMS is using its authority provided by Congress to determine if the drug is considered reasonable and necessary, meaning that the benefits of improvement of cognition outweigh the harms in the Medicare population,” Dr. Fleisher said.
 

Biogen disappointed

Cambridge, Mass.–based Biogen urged the CMS to reconsider its approach to payment for aducanumab. In a statement, the company said Medicare should cover “the class of amyloid-directed therapies with the populations studied in the respective clinical trials and guided by expert recommendations for appropriate use.

“We believe Alzheimer’s patients should have access consistent with other therapies with FDA accelerated approval,” Biogen said in the release.

In the company’s view, the CED approach will “significantly limit patient access to an FDA-approved treatment, especially for underserved patients as evidenced in other CED determinations.

“CEDs can take months to years to initiate, and hundreds of Alzheimer’s patients – the majority of whom are Medicare beneficiaries – are progressing each day from mild to moderate disease stages, where treatment may no longer be an option,” Biogen said.

Drug makers had been worried about CMS opting for CED even before the draft decision was unveiled.
 

Others weigh in

BIO, the trade group for biotechnology companies, urged the CMS to provide access to aducanumab without excess restrictions.

There already are concerns among drug makers about CMS efforts “to impose new coverage barriers – and, in particular, coverage with evidence development,” Crystal Kuntz, vice president of policy and research at BIO, and Andy Cosgrove, the organization’s senior director for policy and research, noted in a July 2021 comment about the aducanumab review.

Medicare should instead continue to provide access to medicines for indications that the FDA has approved, with additional flexibility for off-label indications of cancer drugs, they noted. “We believe this should continue to be the case, to ensure that vulnerable Medicare beneficiaries have necessary access to life-altering and lifesaving medications,” the BIO officials wrote.

However, the CMS also received many pleas from physicians asking the agency to limit use of aducanumab at least until there is evidence that it produces a significant clinical benefit.

In a press release, Howard Fillit, MD, cofounder and chief science officer of the Alzheimer’s Drug Discovery Foundation, applauded the decision, describing it as “the right call.

“This decision supports conducting additional clinical trials, which are needed to obtain further insights into the clinical efficacy and safety profile of this drug in real-world populations. This decision has implications for other drugs in this class in late-stage development. If these trials show more clear and robust clinical efficacy, then it is possible the FDA will give these amyloid monoclonal antibodies full approval, and Medicare would be likely to provide full payment,” he added.

A version of this article first appeared on Medscape.com.

Medicare intends to limit coverage of the controversial Alzheimer’s drug aducanumab (Aduhelm, Biogen) via a special program intended to help assess how well this exorbitantly expensive medication works, federal officials announced Jan. 11.

On Dec. 20, 2021, Biogen announced a plan to reduce the annual U.S. cost of the drug by 50% – from $56,000 to $28,200 – as Centers for Medicare & Medicaid Services officials were deciding on Medicare’s coverage policy for the medication.

In making its proposed coverage decision, the CMS announced it will pay for aducanumab, a monoclonal antibody, under its coverage-with-evidence-development (CED) mechanism. In making its decision, the CMS approached aducanumab as the first of a potential new class of monoclonal antibodies for the treatment of Alzheimer’s disease. Food and Drug Administration–approved drugs in this class would be covered for those with Medicare only if they are enrolled in qualifying clinical trials, the CMS said. The agency will accept public comments on this decision for 30 days.  

In a statement, CMS Administrator Chiquita Brooks-LaSure said the agency is “committed to providing the American public with a clear, trusted, evidence-based decision that is made only after a thorough analysis of public feedback on the benefits and risks of coverage for Medicare patients.”

As previously reported, the FDA approved aducanumab on June 7, 2021, via an accelerated approval process. The approval, which set off a firestorm of controversy that included resignations of three FDA Peripheral and Central Nervous System Drugs Advisory Committee panel members, was granted based on the medication’s ability to reduce beta-amyloid plaque.

Under the accelerated approval mechanism, Biogen still must deliver solid scientific proof that aducanumab has clinically significant disease-modifying effects. However, the final evidence won’t be in any time soon. In its approval letter, the FDA set a 2030 deadline for a final report on this research.

 

‘Unusual but appropriate’ step

The Medicare decision marks something of a shift in the agency’s approach to paying for medications. On a call with reporters, Tamara Syrek Jensen, JD, director of CMS’ Coverage and Analysis Group, admitted that the agency had taken an “unusual but appropriate” step in trying to set a national policy regarding payment for a drug.

On the same call, Lee Fleisher, MD, CMS’ chief medical officer, addressed the challenges presented by aducanumab, given the serious need for treatments for Alzheimer’s disease. “As a practicing physician, I cannot overemphasize the need to understand the risks and benefits of a given treatment in order to better inform patients and their families,” Dr. Fleisher said. “We do know based on some of the evidence that there may be potential promise with this treatment. That’s why it is critical for us to pursue additional scientific evidence.”

The coverage-with-evidence program will allow Medicare to aid in gathering data, while protecting patients, Dr. Fleisher noted.

“CMS is using its authority provided by Congress to determine if the drug is considered reasonable and necessary, meaning that the benefits of improvement of cognition outweigh the harms in the Medicare population,” Dr. Fleisher said.
 

Biogen disappointed

Cambridge, Mass.–based Biogen urged the CMS to reconsider its approach to payment for aducanumab. In a statement, the company said Medicare should cover “the class of amyloid-directed therapies with the populations studied in the respective clinical trials and guided by expert recommendations for appropriate use.

“We believe Alzheimer’s patients should have access consistent with other therapies with FDA accelerated approval,” Biogen said in the release.

In the company’s view, the CED approach will “significantly limit patient access to an FDA-approved treatment, especially for underserved patients as evidenced in other CED determinations.

“CEDs can take months to years to initiate, and hundreds of Alzheimer’s patients – the majority of whom are Medicare beneficiaries – are progressing each day from mild to moderate disease stages, where treatment may no longer be an option,” Biogen said.

Drug makers had been worried about CMS opting for CED even before the draft decision was unveiled.
 

Others weigh in

BIO, the trade group for biotechnology companies, urged the CMS to provide access to aducanumab without excess restrictions.

There already are concerns among drug makers about CMS efforts “to impose new coverage barriers – and, in particular, coverage with evidence development,” Crystal Kuntz, vice president of policy and research at BIO, and Andy Cosgrove, the organization’s senior director for policy and research, noted in a July 2021 comment about the aducanumab review.

Medicare should instead continue to provide access to medicines for indications that the FDA has approved, with additional flexibility for off-label indications of cancer drugs, they noted. “We believe this should continue to be the case, to ensure that vulnerable Medicare beneficiaries have necessary access to life-altering and lifesaving medications,” the BIO officials wrote.

However, the CMS also received many pleas from physicians asking the agency to limit use of aducanumab at least until there is evidence that it produces a significant clinical benefit.

In a press release, Howard Fillit, MD, cofounder and chief science officer of the Alzheimer’s Drug Discovery Foundation, applauded the decision, describing it as “the right call.

“This decision supports conducting additional clinical trials, which are needed to obtain further insights into the clinical efficacy and safety profile of this drug in real-world populations. This decision has implications for other drugs in this class in late-stage development. If these trials show more clear and robust clinical efficacy, then it is possible the FDA will give these amyloid monoclonal antibodies full approval, and Medicare would be likely to provide full payment,” he added.

A version of this article first appeared on Medscape.com.

The number of individuals older than 40 with dementia will nearly triple worldwide and double in the United States by 2050 unless steps are taken to address risk factors, new research suggests.

Results from a study of 195 countries and territories estimates that by 2050, 153 million people are expected to have dementia worldwide – up from 57 million in 2019. In the United States, the number is expected to increase 100%, from an estimated 5.3 million in 2019 to 10.5 million in 2050.

The increase is largely driven by population growth and population aging, but researchers noted that expanding access to education and addressing risk factors such as obesity, high blood sugar, and smoking could blunt the rise in cases.

The study predicts increases in dementia in every country included in the analysis. The sharpest rise is expected in north Africa and the Middle East (367%) and sub-Saharan Africa (357%). The smallest increases will be in high-income countries in Asia Pacific (53%) and western Europe (74%).

Although the United States had the 37th lowest percentage increase across all countries considered, “this expected increase is still large and requires attention from policy and decision-makers,” said coinvestigator Emma Nichols, MPH, a researcher with the Institute for Health Metrics and Evaluation at the University of Washington, Seattle.

The findings were published online Jan. 6, 2022, in The Lancet Public Health (doi: 10.1016/S2468-2667[21]00249-8).
 

Dementia prevalence

For the study, researchers used country-specific estimates of dementia prevalence from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 study to project dementia prevalence globally, by world region, and at the country level.

They also used information on projected trends in four important dementia risk factors (high body mass index, high fasting plasma glucose, smoking, and education) to estimate how changes in these risk factors might impact dementia prevalence between 2019 and 2050.

Despite large increases in the projected number of people living with dementia, age-standardized both-sex prevalence remained stable between 2019 and 2050, with a global percentage change of 0.1% (95% uncertainty interval, –7.5 to 10.8).

Dementia prevalence was higher in women than in men and increased with age, doubling about every 5 years until 85 years of age in both 2019 and 2050 (female-to-male ratio, 1.67; 95% UI, 1.52-1.85).

Projected increases in cases could largely be attributed to population growth and population aging, although their relative importance varied by world region. Population growth contributed most to the increases in sub-Saharan Africa and population aging contributed most to the increases in east Asia.

The countries with the highest expected percentage change in total number of dementia cases between 2019 and 2050 were: Qatar (1,926%), United Arab Emirates (1,795%), Bahrain (1,084%), Oman (943%), Saudi Arabia (898%), Kuwait (850%), Iraq (559%), Maldives (554%), Jordan (522%), and Equatorial Guinea (498%).

The countries with the lowest expected percentage change in total number of dementia cases between 2019 and 2050 were Japan (27%), Bulgaria (37%), Serbia (38%), Lithuania (44%), Greece (45%), Latvia (47%), Croatia (55%), Ukraine (55%), Italy (56%), and Finland (58%).
 

Modifiable risk factors

Researchers also calculated how changes in risk factors might affect dementia prevalence. They found that improvements in global education access would reduce dementia prevalence by an estimated 6.2 million cases worldwide by 2050. However, that decrease would be offset by expected increases in obesity, high blood sugar, and smoking, which investigators estimate will result in an additional 6.8 million dementia cases.

The projections are based on expected trends in population aging, population growth, and risk factor trajectories, but “projections could change if effective interventions for modifiable risk factors are developed and deployed,” Ms. Nichols said.

In 2020, the Lancet Commission on Dementia Prevention, Intervention, and Care issued an update of its 2017 report, identifying 12 modifiable risk factors that could delay or prevent 40% of dementia cases. The risk factors were low education, hypertension, hearing impairment, smoking, midlife obesity, depression, physical inactivity, diabetes, social isolation, excessive alcohol consumption, head injury, and air pollution.

“Countries, including the U.S., should look to develop effective interventions for modifiable risk factors, but also should invest in the resources needed to support those with dementia and their caregivers,” Ms. Nichols said. She added that additional support for research and resources to develop therapeutic interventions is also warranted.
 

Oversimplifying mechanisms?

In an accompanying commentary, Michaël Schwarzinger, MD, and Carole Dufouil, PhD, of Bordeaux (France) University Hospital, noted that the authors’ efforts to build on GBD 2019 oversimplify the underlying mechanisms that cause dementia. The authors “provide somehow apocalyptic projections that do not factor in advisable changes in lifestyle over the lifetime,” they wrote.

“There is a considerable and urgent need to reinforce a public health approach towards dementia to better inform the people and decision-makers about the appropriate means to delay or avoid these dire projections,” the editorialists added.

The study was funded by the Bill and Melinda Gates Foundation and Gates Ventures. Ms. Nichols and the editorialists disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

The number of individuals older than 40 with dementia will nearly triple worldwide and double in the United States by 2050 unless steps are taken to address risk factors, new research suggests.

Results from a study of 195 countries and territories estimates that by 2050, 153 million people are expected to have dementia worldwide – up from 57 million in 2019. In the United States, the number is expected to increase 100%, from an estimated 5.3 million in 2019 to 10.5 million in 2050.

The increase is largely driven by population growth and population aging, but researchers noted that expanding access to education and addressing risk factors such as obesity, high blood sugar, and smoking could blunt the rise in cases.

The study predicts increases in dementia in every country included in the analysis. The sharpest rise is expected in north Africa and the Middle East (367%) and sub-Saharan Africa (357%). The smallest increases will be in high-income countries in Asia Pacific (53%) and western Europe (74%).

Although the United States had the 37th lowest percentage increase across all countries considered, “this expected increase is still large and requires attention from policy and decision-makers,” said coinvestigator Emma Nichols, MPH, a researcher with the Institute for Health Metrics and Evaluation at the University of Washington, Seattle.

The findings were published online Jan. 6, 2022, in The Lancet Public Health (doi: 10.1016/S2468-2667[21]00249-8).
 

Dementia prevalence

For the study, researchers used country-specific estimates of dementia prevalence from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 study to project dementia prevalence globally, by world region, and at the country level.

They also used information on projected trends in four important dementia risk factors (high body mass index, high fasting plasma glucose, smoking, and education) to estimate how changes in these risk factors might impact dementia prevalence between 2019 and 2050.

Despite large increases in the projected number of people living with dementia, age-standardized both-sex prevalence remained stable between 2019 and 2050, with a global percentage change of 0.1% (95% uncertainty interval, –7.5 to 10.8).

Dementia prevalence was higher in women than in men and increased with age, doubling about every 5 years until 85 years of age in both 2019 and 2050 (female-to-male ratio, 1.67; 95% UI, 1.52-1.85).

Projected increases in cases could largely be attributed to population growth and population aging, although their relative importance varied by world region. Population growth contributed most to the increases in sub-Saharan Africa and population aging contributed most to the increases in east Asia.

The countries with the highest expected percentage change in total number of dementia cases between 2019 and 2050 were: Qatar (1,926%), United Arab Emirates (1,795%), Bahrain (1,084%), Oman (943%), Saudi Arabia (898%), Kuwait (850%), Iraq (559%), Maldives (554%), Jordan (522%), and Equatorial Guinea (498%).

The countries with the lowest expected percentage change in total number of dementia cases between 2019 and 2050 were Japan (27%), Bulgaria (37%), Serbia (38%), Lithuania (44%), Greece (45%), Latvia (47%), Croatia (55%), Ukraine (55%), Italy (56%), and Finland (58%).
 

Modifiable risk factors

Researchers also calculated how changes in risk factors might affect dementia prevalence. They found that improvements in global education access would reduce dementia prevalence by an estimated 6.2 million cases worldwide by 2050. However, that decrease would be offset by expected increases in obesity, high blood sugar, and smoking, which investigators estimate will result in an additional 6.8 million dementia cases.

The projections are based on expected trends in population aging, population growth, and risk factor trajectories, but “projections could change if effective interventions for modifiable risk factors are developed and deployed,” Ms. Nichols said.

In 2020, the Lancet Commission on Dementia Prevention, Intervention, and Care issued an update of its 2017 report, identifying 12 modifiable risk factors that could delay or prevent 40% of dementia cases. The risk factors were low education, hypertension, hearing impairment, smoking, midlife obesity, depression, physical inactivity, diabetes, social isolation, excessive alcohol consumption, head injury, and air pollution.

“Countries, including the U.S., should look to develop effective interventions for modifiable risk factors, but also should invest in the resources needed to support those with dementia and their caregivers,” Ms. Nichols said. She added that additional support for research and resources to develop therapeutic interventions is also warranted.
 

Oversimplifying mechanisms?

In an accompanying commentary, Michaël Schwarzinger, MD, and Carole Dufouil, PhD, of Bordeaux (France) University Hospital, noted that the authors’ efforts to build on GBD 2019 oversimplify the underlying mechanisms that cause dementia. The authors “provide somehow apocalyptic projections that do not factor in advisable changes in lifestyle over the lifetime,” they wrote.

“There is a considerable and urgent need to reinforce a public health approach towards dementia to better inform the people and decision-makers about the appropriate means to delay or avoid these dire projections,” the editorialists added.

The study was funded by the Bill and Melinda Gates Foundation and Gates Ventures. Ms. Nichols and the editorialists disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

The number of individuals older than 40 with dementia will nearly triple worldwide and double in the United States by 2050 unless steps are taken to address risk factors, new research suggests.

Results from a study of 195 countries and territories estimates that by 2050, 153 million people are expected to have dementia worldwide – up from 57 million in 2019. In the United States, the number is expected to increase 100%, from an estimated 5.3 million in 2019 to 10.5 million in 2050.

The increase is largely driven by population growth and population aging, but researchers noted that expanding access to education and addressing risk factors such as obesity, high blood sugar, and smoking could blunt the rise in cases.

The study predicts increases in dementia in every country included in the analysis. The sharpest rise is expected in north Africa and the Middle East (367%) and sub-Saharan Africa (357%). The smallest increases will be in high-income countries in Asia Pacific (53%) and western Europe (74%).

Although the United States had the 37th lowest percentage increase across all countries considered, “this expected increase is still large and requires attention from policy and decision-makers,” said coinvestigator Emma Nichols, MPH, a researcher with the Institute for Health Metrics and Evaluation at the University of Washington, Seattle.

The findings were published online Jan. 6, 2022, in The Lancet Public Health (doi: 10.1016/S2468-2667[21]00249-8).
 

Dementia prevalence

For the study, researchers used country-specific estimates of dementia prevalence from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 study to project dementia prevalence globally, by world region, and at the country level.

They also used information on projected trends in four important dementia risk factors (high body mass index, high fasting plasma glucose, smoking, and education) to estimate how changes in these risk factors might impact dementia prevalence between 2019 and 2050.

Despite large increases in the projected number of people living with dementia, age-standardized both-sex prevalence remained stable between 2019 and 2050, with a global percentage change of 0.1% (95% uncertainty interval, –7.5 to 10.8).

Dementia prevalence was higher in women than in men and increased with age, doubling about every 5 years until 85 years of age in both 2019 and 2050 (female-to-male ratio, 1.67; 95% UI, 1.52-1.85).

Projected increases in cases could largely be attributed to population growth and population aging, although their relative importance varied by world region. Population growth contributed most to the increases in sub-Saharan Africa and population aging contributed most to the increases in east Asia.

The countries with the highest expected percentage change in total number of dementia cases between 2019 and 2050 were: Qatar (1,926%), United Arab Emirates (1,795%), Bahrain (1,084%), Oman (943%), Saudi Arabia (898%), Kuwait (850%), Iraq (559%), Maldives (554%), Jordan (522%), and Equatorial Guinea (498%).

The countries with the lowest expected percentage change in total number of dementia cases between 2019 and 2050 were Japan (27%), Bulgaria (37%), Serbia (38%), Lithuania (44%), Greece (45%), Latvia (47%), Croatia (55%), Ukraine (55%), Italy (56%), and Finland (58%).
 

Modifiable risk factors

Researchers also calculated how changes in risk factors might affect dementia prevalence. They found that improvements in global education access would reduce dementia prevalence by an estimated 6.2 million cases worldwide by 2050. However, that decrease would be offset by expected increases in obesity, high blood sugar, and smoking, which investigators estimate will result in an additional 6.8 million dementia cases.

The projections are based on expected trends in population aging, population growth, and risk factor trajectories, but “projections could change if effective interventions for modifiable risk factors are developed and deployed,” Ms. Nichols said.

In 2020, the Lancet Commission on Dementia Prevention, Intervention, and Care issued an update of its 2017 report, identifying 12 modifiable risk factors that could delay or prevent 40% of dementia cases. The risk factors were low education, hypertension, hearing impairment, smoking, midlife obesity, depression, physical inactivity, diabetes, social isolation, excessive alcohol consumption, head injury, and air pollution.

“Countries, including the U.S., should look to develop effective interventions for modifiable risk factors, but also should invest in the resources needed to support those with dementia and their caregivers,” Ms. Nichols said. She added that additional support for research and resources to develop therapeutic interventions is also warranted.
 

Oversimplifying mechanisms?

In an accompanying commentary, Michaël Schwarzinger, MD, and Carole Dufouil, PhD, of Bordeaux (France) University Hospital, noted that the authors’ efforts to build on GBD 2019 oversimplify the underlying mechanisms that cause dementia. The authors “provide somehow apocalyptic projections that do not factor in advisable changes in lifestyle over the lifetime,” they wrote.

“There is a considerable and urgent need to reinforce a public health approach towards dementia to better inform the people and decision-makers about the appropriate means to delay or avoid these dire projections,” the editorialists added.

The study was funded by the Bill and Melinda Gates Foundation and Gates Ventures. Ms. Nichols and the editorialists disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Even though men in midlife have more cardiovascular (CV) conditions and risk factors than women of the same age, women are more affected by these conditions in terms of cognitive decline, new research suggests.

Analyses of almost 1,400 participants in the population-based Mayo Clinic Study of Aging showed that diabetes, dyslipidemia, and coronary heart disease (CHD) all had stronger associations with global cognitive decline in women than in men.

“All men and women should be treated for cardiovascular risk factors and conditions, but this study really highlights the importance of very early and perhaps more aggressive treatment in women with these conditions,” co-investigator Michelle M. Mielke, PhD, professor of epidemiology and neurology, Mayo Clinic, Rochester, Minn., told this news organization.

The findings were published online Jan. 5 in Neurology.
 

Assessing sex differences

Most previous studies in this area have focused on CV risk factors in midlife in relation to late-life dementia (after age 75) or on late-life vascular risk factors and late-life dementia, Dr. Mielke noted.

However, a few recent studies have suggested vascular risk factors can affect cognition even in midlife. The current investigators sought to determine whether there are sex differences in these associations.

They assessed 1,857 nondemented participants aged 50 to 69 years from the Mayo Clinic Study on Aging. The mean education level was 14.9 years, and the mean body mass index (BMI) was 29.7.

Among the participants, 78.9% had at least one CV condition or risk factor, and the proportion was higher in men than women (83.4% vs. 74.5%; P < .0001).

Frequency of each individual CV condition or risk factor was also higher in men than women, and they had more years of education and higher BMI but took fewer medications.

Every 15 months, participants had an in-person interview and physical examination that included a neurologic assessment and short test of memory.

The neuropsychological battery included nine tests across four domains: memory, language, executive function, and visuospatial skills. Researchers calculated z-scores for these domains and for global cognition.
 

Multiple cognitive domains

Whereas this study evaluated multiple cognitive domains, most previous research has focused on global cognitive decline and/or decline in only one or two cognitive domains, the investigators note.

They collected information from medical records on CV conditions such as CHD, arrhythmias, congestive heart failure, peripheral vascular disease (PVD), and stroke; and CV risk factors such as hypertension, diabetes, dyslipidemia, smoking status, and BMI.

Because of the small number of patients with stroke and PVD, these were classified as “other cardiovascular conditions” in the statistical analysis.

Researchers adjusted for sex, age, years of education, depressive symptoms, comorbidities, medications, and apolipoprotein E (APOE) genotyping. The mean follow-up was 3 years and did not differ by sex.

As some participants didn’t have a follow-up visit, the current analysis included 1,394 individuals. Those without follow-up visits were younger, had less education and more comorbidities, and took more medications compared with those with a follow-up.

Results showed most CV conditions were more strongly associated with cognitive function among women than men. For example, CHD was associated with global decline only in women (P < .05).

CHD, diabetes, and dyslipidemia were associated with language decline in women only (all, P < .05), but congestive heart failure was significantly associated with language decline in men only.

Dr. Mielke cautioned about reading too much into the language results for women.

“It’s an intriguing finding and definitely we need to follow up on it,” she said. However, “more studies are needed to examine sex differences before we start saying it only has an effect on language.”
 

‘Treat aggressively and right away’

The researchers were somewhat surprised by the study findings. Because there is a higher prevalence of CV conditions and risk factors in men, they presumed men would be more affected by these conditions, said Dr. Mielke.

“But that’s not what we saw; we saw the reverse. It was actually the women who were affected more by these cardiovascular risk factors and conditions,” she said.

As midlife is when women enter menopause, fluctuating estrogen levels may help explain the differential impact on cognition among women. But Dr. Mielke said she wants to “move beyond” just looking at hormones.

She pointed out there are a variety of psychosocial factors that may also contribute to an imbalance in the cognitive impact of CV conditions on women.

“Midlife is when many women are still taking care of their children at home, are also taking care of their adult parents, and may be undergoing more stress while continuing to do a job,” Dr. Miekle said.

Structural brain development and genetics may also contribute to the greater effect on cognition in women, the investigators note.

Dr. Mielke stressed that the current study only identifies associations. “The next steps are to understand what some of the underlying mechanisms for this are,” she said.

In the meantime, these new results suggest middle-aged women with high blood pressure, cholesterol, or glucose measures “should be treated aggressively and right away” said Dr. Mielke.

“For example, for women who are just starting to become hypertensive, clinicians should treat them right away and not watch and wait.”

Study limitations cited include that its sample was limited to Olmsted County, Minnesota – so results may not be generalized to other populations. Also, as researchers combined PVD and stroke into one group, larger sample sizes are needed, especially for stroke. Another limitation was the study did not have information on duration of all CV conditions or risk factors.
 

Helpful for tailoring interventions?

Commenting on the study, Glen R. Finney, MD, director, Memory and Cognition Program, Geisinger Health Clinic, Wilkes-Barre, Pennsylvania, said the results are important.

“The more we understand about risk factors for the development of Alzheimer’s disease and related dementias, the better we understand how we can reduce the risks,” said Dr. Finney, who was not involved with the research.

Awareness that CV conditions are major risk factors in midlife has been “definitely rising,” said Dr. Finney. “Many studies originally were looking at late life and are now looking more at earlier in the disease process, and I think that’s important.”

Understanding how sex, ethnicity, and other demographic variables affect risks can help to “tailor interventions” for individual patients, he said.

The study was supported by the National Institutes of Health, the GHR Foundation, and the Rochester Epidemiology Project. Dr. Mielke is a consultant for Biogen and Brain Protection Company and is on the editorial boards of Neurology and Alzheimer’s and Dementia. Dr. Finney has reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Even though men in midlife have more cardiovascular (CV) conditions and risk factors than women of the same age, women are more affected by these conditions in terms of cognitive decline, new research suggests.

Analyses of almost 1,400 participants in the population-based Mayo Clinic Study of Aging showed that diabetes, dyslipidemia, and coronary heart disease (CHD) all had stronger associations with global cognitive decline in women than in men.

“All men and women should be treated for cardiovascular risk factors and conditions, but this study really highlights the importance of very early and perhaps more aggressive treatment in women with these conditions,” co-investigator Michelle M. Mielke, PhD, professor of epidemiology and neurology, Mayo Clinic, Rochester, Minn., told this news organization.

The findings were published online Jan. 5 in Neurology.
 

Assessing sex differences

Most previous studies in this area have focused on CV risk factors in midlife in relation to late-life dementia (after age 75) or on late-life vascular risk factors and late-life dementia, Dr. Mielke noted.

However, a few recent studies have suggested vascular risk factors can affect cognition even in midlife. The current investigators sought to determine whether there are sex differences in these associations.

They assessed 1,857 nondemented participants aged 50 to 69 years from the Mayo Clinic Study on Aging. The mean education level was 14.9 years, and the mean body mass index (BMI) was 29.7.

Among the participants, 78.9% had at least one CV condition or risk factor, and the proportion was higher in men than women (83.4% vs. 74.5%; P < .0001).

Frequency of each individual CV condition or risk factor was also higher in men than women, and they had more years of education and higher BMI but took fewer medications.

Every 15 months, participants had an in-person interview and physical examination that included a neurologic assessment and short test of memory.

The neuropsychological battery included nine tests across four domains: memory, language, executive function, and visuospatial skills. Researchers calculated z-scores for these domains and for global cognition.
 

Multiple cognitive domains

Whereas this study evaluated multiple cognitive domains, most previous research has focused on global cognitive decline and/or decline in only one or two cognitive domains, the investigators note.

They collected information from medical records on CV conditions such as CHD, arrhythmias, congestive heart failure, peripheral vascular disease (PVD), and stroke; and CV risk factors such as hypertension, diabetes, dyslipidemia, smoking status, and BMI.

Because of the small number of patients with stroke and PVD, these were classified as “other cardiovascular conditions” in the statistical analysis.

Researchers adjusted for sex, age, years of education, depressive symptoms, comorbidities, medications, and apolipoprotein E (APOE) genotyping. The mean follow-up was 3 years and did not differ by sex.

As some participants didn’t have a follow-up visit, the current analysis included 1,394 individuals. Those without follow-up visits were younger, had less education and more comorbidities, and took more medications compared with those with a follow-up.

Results showed most CV conditions were more strongly associated with cognitive function among women than men. For example, CHD was associated with global decline only in women (P < .05).

CHD, diabetes, and dyslipidemia were associated with language decline in women only (all, P < .05), but congestive heart failure was significantly associated with language decline in men only.

Dr. Mielke cautioned about reading too much into the language results for women.

“It’s an intriguing finding and definitely we need to follow up on it,” she said. However, “more studies are needed to examine sex differences before we start saying it only has an effect on language.”
 

‘Treat aggressively and right away’

The researchers were somewhat surprised by the study findings. Because there is a higher prevalence of CV conditions and risk factors in men, they presumed men would be more affected by these conditions, said Dr. Mielke.

“But that’s not what we saw; we saw the reverse. It was actually the women who were affected more by these cardiovascular risk factors and conditions,” she said.

As midlife is when women enter menopause, fluctuating estrogen levels may help explain the differential impact on cognition among women. But Dr. Mielke said she wants to “move beyond” just looking at hormones.

She pointed out there are a variety of psychosocial factors that may also contribute to an imbalance in the cognitive impact of CV conditions on women.

“Midlife is when many women are still taking care of their children at home, are also taking care of their adult parents, and may be undergoing more stress while continuing to do a job,” Dr. Miekle said.

Structural brain development and genetics may also contribute to the greater effect on cognition in women, the investigators note.

Dr. Mielke stressed that the current study only identifies associations. “The next steps are to understand what some of the underlying mechanisms for this are,” she said.

In the meantime, these new results suggest middle-aged women with high blood pressure, cholesterol, or glucose measures “should be treated aggressively and right away” said Dr. Mielke.

“For example, for women who are just starting to become hypertensive, clinicians should treat them right away and not watch and wait.”

Study limitations cited include that its sample was limited to Olmsted County, Minnesota – so results may not be generalized to other populations. Also, as researchers combined PVD and stroke into one group, larger sample sizes are needed, especially for stroke. Another limitation was the study did not have information on duration of all CV conditions or risk factors.
 

Helpful for tailoring interventions?

Commenting on the study, Glen R. Finney, MD, director, Memory and Cognition Program, Geisinger Health Clinic, Wilkes-Barre, Pennsylvania, said the results are important.

“The more we understand about risk factors for the development of Alzheimer’s disease and related dementias, the better we understand how we can reduce the risks,” said Dr. Finney, who was not involved with the research.

Awareness that CV conditions are major risk factors in midlife has been “definitely rising,” said Dr. Finney. “Many studies originally were looking at late life and are now looking more at earlier in the disease process, and I think that’s important.”

Understanding how sex, ethnicity, and other demographic variables affect risks can help to “tailor interventions” for individual patients, he said.

The study was supported by the National Institutes of Health, the GHR Foundation, and the Rochester Epidemiology Project. Dr. Mielke is a consultant for Biogen and Brain Protection Company and is on the editorial boards of Neurology and Alzheimer’s and Dementia. Dr. Finney has reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Even though men in midlife have more cardiovascular (CV) conditions and risk factors than women of the same age, women are more affected by these conditions in terms of cognitive decline, new research suggests.

Analyses of almost 1,400 participants in the population-based Mayo Clinic Study of Aging showed that diabetes, dyslipidemia, and coronary heart disease (CHD) all had stronger associations with global cognitive decline in women than in men.

“All men and women should be treated for cardiovascular risk factors and conditions, but this study really highlights the importance of very early and perhaps more aggressive treatment in women with these conditions,” co-investigator Michelle M. Mielke, PhD, professor of epidemiology and neurology, Mayo Clinic, Rochester, Minn., told this news organization.

The findings were published online Jan. 5 in Neurology.
 

Assessing sex differences

Most previous studies in this area have focused on CV risk factors in midlife in relation to late-life dementia (after age 75) or on late-life vascular risk factors and late-life dementia, Dr. Mielke noted.

However, a few recent studies have suggested vascular risk factors can affect cognition even in midlife. The current investigators sought to determine whether there are sex differences in these associations.

They assessed 1,857 nondemented participants aged 50 to 69 years from the Mayo Clinic Study on Aging. The mean education level was 14.9 years, and the mean body mass index (BMI) was 29.7.

Among the participants, 78.9% had at least one CV condition or risk factor, and the proportion was higher in men than women (83.4% vs. 74.5%; P < .0001).

Frequency of each individual CV condition or risk factor was also higher in men than women, and they had more years of education and higher BMI but took fewer medications.

Every 15 months, participants had an in-person interview and physical examination that included a neurologic assessment and short test of memory.

The neuropsychological battery included nine tests across four domains: memory, language, executive function, and visuospatial skills. Researchers calculated z-scores for these domains and for global cognition.
 

Multiple cognitive domains

Whereas this study evaluated multiple cognitive domains, most previous research has focused on global cognitive decline and/or decline in only one or two cognitive domains, the investigators note.

They collected information from medical records on CV conditions such as CHD, arrhythmias, congestive heart failure, peripheral vascular disease (PVD), and stroke; and CV risk factors such as hypertension, diabetes, dyslipidemia, smoking status, and BMI.

Because of the small number of patients with stroke and PVD, these were classified as “other cardiovascular conditions” in the statistical analysis.

Researchers adjusted for sex, age, years of education, depressive symptoms, comorbidities, medications, and apolipoprotein E (APOE) genotyping. The mean follow-up was 3 years and did not differ by sex.

As some participants didn’t have a follow-up visit, the current analysis included 1,394 individuals. Those without follow-up visits were younger, had less education and more comorbidities, and took more medications compared with those with a follow-up.

Results showed most CV conditions were more strongly associated with cognitive function among women than men. For example, CHD was associated with global decline only in women (P < .05).

CHD, diabetes, and dyslipidemia were associated with language decline in women only (all, P < .05), but congestive heart failure was significantly associated with language decline in men only.

Dr. Mielke cautioned about reading too much into the language results for women.

“It’s an intriguing finding and definitely we need to follow up on it,” she said. However, “more studies are needed to examine sex differences before we start saying it only has an effect on language.”
 

‘Treat aggressively and right away’

The researchers were somewhat surprised by the study findings. Because there is a higher prevalence of CV conditions and risk factors in men, they presumed men would be more affected by these conditions, said Dr. Mielke.

“But that’s not what we saw; we saw the reverse. It was actually the women who were affected more by these cardiovascular risk factors and conditions,” she said.

As midlife is when women enter menopause, fluctuating estrogen levels may help explain the differential impact on cognition among women. But Dr. Mielke said she wants to “move beyond” just looking at hormones.

She pointed out there are a variety of psychosocial factors that may also contribute to an imbalance in the cognitive impact of CV conditions on women.

“Midlife is when many women are still taking care of their children at home, are also taking care of their adult parents, and may be undergoing more stress while continuing to do a job,” Dr. Miekle said.

Structural brain development and genetics may also contribute to the greater effect on cognition in women, the investigators note.

Dr. Mielke stressed that the current study only identifies associations. “The next steps are to understand what some of the underlying mechanisms for this are,” she said.

In the meantime, these new results suggest middle-aged women with high blood pressure, cholesterol, or glucose measures “should be treated aggressively and right away” said Dr. Mielke.

“For example, for women who are just starting to become hypertensive, clinicians should treat them right away and not watch and wait.”

Study limitations cited include that its sample was limited to Olmsted County, Minnesota – so results may not be generalized to other populations. Also, as researchers combined PVD and stroke into one group, larger sample sizes are needed, especially for stroke. Another limitation was the study did not have information on duration of all CV conditions or risk factors.
 

Helpful for tailoring interventions?

Commenting on the study, Glen R. Finney, MD, director, Memory and Cognition Program, Geisinger Health Clinic, Wilkes-Barre, Pennsylvania, said the results are important.

“The more we understand about risk factors for the development of Alzheimer’s disease and related dementias, the better we understand how we can reduce the risks,” said Dr. Finney, who was not involved with the research.

Awareness that CV conditions are major risk factors in midlife has been “definitely rising,” said Dr. Finney. “Many studies originally were looking at late life and are now looking more at earlier in the disease process, and I think that’s important.”

Understanding how sex, ethnicity, and other demographic variables affect risks can help to “tailor interventions” for individual patients, he said.

The study was supported by the National Institutes of Health, the GHR Foundation, and the Rochester Epidemiology Project. Dr. Mielke is a consultant for Biogen and Brain Protection Company and is on the editorial boards of Neurology and Alzheimer’s and Dementia. Dr. Finney has reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

People who have had prior SARS-CoV-2 infection report significantly more symptoms of cognitive dysfunction and specifically executive dysfunction than people in the general population with no such infection, according to new data published on the preprint server medRxiv.

Researchers, led by Peter A. Hall, PhD, with the University of Waterloo (Ont.), found that COVID infection is associated with executive dysfunction among young and middle-aged adults, including for those not exposed to intubation or hospitalization.

The findings have not been peer reviewed.

The study included a representative cohort of 1,958 community-dwelling young and middle-aged adults. It used a balanced proportion of infected and uninfected people to estimate the link between SARS-CoV-2 infection and cognitive/executive dysfunction.

The authors noted that the survey was conducted from Sept. 28 to Oct. 21, 2021, when the primary variant in Canada was Delta.

The research was a cross-sectional observational study with data from the ongoing Canadian COVID-19 Experiences Survey. It included equal representation of vaccinated and vaccine-hesitant adults aged 18-54 years. COVID-19 symptoms ranged from negligible to life-threatening cases requiring hospitalization.

Half in the cohort (50.2%) received two vaccine shots; 43.3% had received no shots; and 5.5% received one shot, but were not intending to receive a second shot.
 

Dose-response relationship

According to the paper, those with prior COVID-19 infection, regardless of symptom severity, reported a significantly higher number of symptoms of executive dysfunction than their noninfected counterparts (mechanical adjustment, 1.63, standard error, 0.08; 95% confidence interval, 1.47-1.80; P = .001).

The researchers also found a dose-response relationship between COVID-19 symptom severity and cognitive dysfunction. Those with moderate and very/extremely severe COVID-19 symptoms were linked with significantly greater dysfunction.

“This reinforces what we’re hearing about – that COVID is not ‘one and done.’ It can have lasting and quite subtle and damaging effects on the human body,” William Schaffner, MD, infectious disease specialist with Vanderbilt University, Nashville, Tenn., said in an interview.

Measuring executive functioning – including the ability to make sound decisions – is something other studies haven’t typically addressed, he said.

Men were likely to report more cognitive dysfunction symptoms than women (beta, 0.15; P < .001). Younger adults (25-39 years) were more likely to experience cognitive dysfunction than those age 40-54 (beta, 0.30; P < .001).

Dr. Schaffner said it was troubling that young people are more likely to experience the dysfunction.

“When we think of ‘brain fog’ we think of older persons who are already predisposed to have more memory lapses as they get older,” he said.

The link between cognitive dysfunction and COVID-19 infection has been shown in other studies, but many have not used representative samples and have not compared results with noninfected controls in the general population, the authors wrote.

Executive dysfunction was measured using four questions from the Deficits in Executive Functioning Scale. Respondents were asked how often they have experienced these scenarios in the past 6 months:
 

• “I am unable to inhibit my reactions or responses to events or to other people.”
• “I make impulsive comments to others.”
• “I am likely to do things without considering the consequences for doing them.”
• “I act without thinking.”

“This makes it even more important that we talk about vaccination,” Dr. Schaffner said, “because clearly the more seriously ill you are, the more likely this sort of thing is likely to happen and vaccines have been shown time and again to avert hospitalizations and more serious illness. It also makes more important the monoclonal antibody treatments we have and the antivirals, which will prevent the evolution of mild disease into something more serious.”

This research was supported by a grant from the Canadian Institutes for Health Research, Institute for Population and Public Health. The study authors and Dr. Schaffner disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

People who have had prior SARS-CoV-2 infection report significantly more symptoms of cognitive dysfunction and specifically executive dysfunction than people in the general population with no such infection, according to new data published on the preprint server medRxiv.

Researchers, led by Peter A. Hall, PhD, with the University of Waterloo (Ont.), found that COVID infection is associated with executive dysfunction among young and middle-aged adults, including for those not exposed to intubation or hospitalization.

The findings have not been peer reviewed.

The study included a representative cohort of 1,958 community-dwelling young and middle-aged adults. It used a balanced proportion of infected and uninfected people to estimate the link between SARS-CoV-2 infection and cognitive/executive dysfunction.

The authors noted that the survey was conducted from Sept. 28 to Oct. 21, 2021, when the primary variant in Canada was Delta.

The research was a cross-sectional observational study with data from the ongoing Canadian COVID-19 Experiences Survey. It included equal representation of vaccinated and vaccine-hesitant adults aged 18-54 years. COVID-19 symptoms ranged from negligible to life-threatening cases requiring hospitalization.

Half in the cohort (50.2%) received two vaccine shots; 43.3% had received no shots; and 5.5% received one shot, but were not intending to receive a second shot.
 

Dose-response relationship

According to the paper, those with prior COVID-19 infection, regardless of symptom severity, reported a significantly higher number of symptoms of executive dysfunction than their noninfected counterparts (mechanical adjustment, 1.63, standard error, 0.08; 95% confidence interval, 1.47-1.80; P = .001).

The researchers also found a dose-response relationship between COVID-19 symptom severity and cognitive dysfunction. Those with moderate and very/extremely severe COVID-19 symptoms were linked with significantly greater dysfunction.

“This reinforces what we’re hearing about – that COVID is not ‘one and done.’ It can have lasting and quite subtle and damaging effects on the human body,” William Schaffner, MD, infectious disease specialist with Vanderbilt University, Nashville, Tenn., said in an interview.

Measuring executive functioning – including the ability to make sound decisions – is something other studies haven’t typically addressed, he said.

Men were likely to report more cognitive dysfunction symptoms than women (beta, 0.15; P < .001). Younger adults (25-39 years) were more likely to experience cognitive dysfunction than those age 40-54 (beta, 0.30; P < .001).

Dr. Schaffner said it was troubling that young people are more likely to experience the dysfunction.

“When we think of ‘brain fog’ we think of older persons who are already predisposed to have more memory lapses as they get older,” he said.

The link between cognitive dysfunction and COVID-19 infection has been shown in other studies, but many have not used representative samples and have not compared results with noninfected controls in the general population, the authors wrote.

Executive dysfunction was measured using four questions from the Deficits in Executive Functioning Scale. Respondents were asked how often they have experienced these scenarios in the past 6 months:
 

• “I am unable to inhibit my reactions or responses to events or to other people.”
• “I make impulsive comments to others.”
• “I am likely to do things without considering the consequences for doing them.”
• “I act without thinking.”

“This makes it even more important that we talk about vaccination,” Dr. Schaffner said, “because clearly the more seriously ill you are, the more likely this sort of thing is likely to happen and vaccines have been shown time and again to avert hospitalizations and more serious illness. It also makes more important the monoclonal antibody treatments we have and the antivirals, which will prevent the evolution of mild disease into something more serious.”

This research was supported by a grant from the Canadian Institutes for Health Research, Institute for Population and Public Health. The study authors and Dr. Schaffner disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

People who have had prior SARS-CoV-2 infection report significantly more symptoms of cognitive dysfunction and specifically executive dysfunction than people in the general population with no such infection, according to new data published on the preprint server medRxiv.

Researchers, led by Peter A. Hall, PhD, with the University of Waterloo (Ont.), found that COVID infection is associated with executive dysfunction among young and middle-aged adults, including for those not exposed to intubation or hospitalization.

The findings have not been peer reviewed.

The study included a representative cohort of 1,958 community-dwelling young and middle-aged adults. It used a balanced proportion of infected and uninfected people to estimate the link between SARS-CoV-2 infection and cognitive/executive dysfunction.

The authors noted that the survey was conducted from Sept. 28 to Oct. 21, 2021, when the primary variant in Canada was Delta.

The research was a cross-sectional observational study with data from the ongoing Canadian COVID-19 Experiences Survey. It included equal representation of vaccinated and vaccine-hesitant adults aged 18-54 years. COVID-19 symptoms ranged from negligible to life-threatening cases requiring hospitalization.

Half in the cohort (50.2%) received two vaccine shots; 43.3% had received no shots; and 5.5% received one shot, but were not intending to receive a second shot.
 

Dose-response relationship

According to the paper, those with prior COVID-19 infection, regardless of symptom severity, reported a significantly higher number of symptoms of executive dysfunction than their noninfected counterparts (mechanical adjustment, 1.63, standard error, 0.08; 95% confidence interval, 1.47-1.80; P = .001).

The researchers also found a dose-response relationship between COVID-19 symptom severity and cognitive dysfunction. Those with moderate and very/extremely severe COVID-19 symptoms were linked with significantly greater dysfunction.

“This reinforces what we’re hearing about – that COVID is not ‘one and done.’ It can have lasting and quite subtle and damaging effects on the human body,” William Schaffner, MD, infectious disease specialist with Vanderbilt University, Nashville, Tenn., said in an interview.

Measuring executive functioning – including the ability to make sound decisions – is something other studies haven’t typically addressed, he said.

Men were likely to report more cognitive dysfunction symptoms than women (beta, 0.15; P < .001). Younger adults (25-39 years) were more likely to experience cognitive dysfunction than those age 40-54 (beta, 0.30; P < .001).

Dr. Schaffner said it was troubling that young people are more likely to experience the dysfunction.

“When we think of ‘brain fog’ we think of older persons who are already predisposed to have more memory lapses as they get older,” he said.

The link between cognitive dysfunction and COVID-19 infection has been shown in other studies, but many have not used representative samples and have not compared results with noninfected controls in the general population, the authors wrote.

Executive dysfunction was measured using four questions from the Deficits in Executive Functioning Scale. Respondents were asked how often they have experienced these scenarios in the past 6 months:
 

• “I am unable to inhibit my reactions or responses to events or to other people.”
• “I make impulsive comments to others.”
• “I am likely to do things without considering the consequences for doing them.”
• “I act without thinking.”

“This makes it even more important that we talk about vaccination,” Dr. Schaffner said, “because clearly the more seriously ill you are, the more likely this sort of thing is likely to happen and vaccines have been shown time and again to avert hospitalizations and more serious illness. It also makes more important the monoclonal antibody treatments we have and the antivirals, which will prevent the evolution of mild disease into something more serious.”

This research was supported by a grant from the Canadian Institutes for Health Research, Institute for Population and Public Health. The study authors and Dr. Schaffner disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Researchers have known for some time that depression is associated with Alzheimer’s disease (AD), but a causal link has been elusive. Now, using newly available data, they have uncovered genetic evidence of a causal role for depression in AD.

As depression typically affects those in early or midlife and dementia often occurs in later life, “it’s fascinating to see a connection between the two brain illnesses that manifest in different time windows,” coinvestigator Aliza P. Wingo, MD, associate professor of psychiatry and behavioral science, Emory University, Atlanta, said in an interview.

“If we can treat the depression early on, we may help reduce risk for dementia for our patients later in life,” Dr. Wingo said.

The findings were published online Dec. 16, 2021, in Biological Psychiatry.

Postmortem data

The investigators, who are all from the Emory University Center for Neurodegenerative Disease, wanted to clarify the genetic basis underlying the association between the established link between depression and dementia risk.

They used data from the largest and most recent genomewide association studies (GWAS). These included a 2019 analysis of depression among 807,553 individuals and a 2019 study of AD among 455,258 individuals, all of European ancestry. For sensitivity analyses, they used results from two additional AD GWAS.

The researchers also accessed postmortem brain samples from participants in the Religious Orders Study (ROS) and the Rush Memory and Aging Project (MAP). These participants were cognitively normal at enrollment, underwent annual clinical evaluations, and agreed to donate their brains.

They also assessed brain samples donated by participants in the Banner Sun Health Research Institute longitudinal study of healthy aging, Alzheimer’s, and Parkinson’s disease.

The brain samples allowed researchers to use deep brain proteomic data to help determine molecular links between depression and AD.

After quality control, the analysis included 8,356 proteins in 391 ROS/MAP participants and 7,854 proteins in 196 Banner participants.

Results showed a small but significant positive genetic correlation between depression and AD, suggesting the two conditions have a shared genetic basis.

The investigators also applied a framework called “Mendelian randomization” to determine causality between depression and AD.

After assessing the effect of 115 independent single-nucleotide polymorphisms (SNPs) from the GWAS of depression, they uncovered significant evidence “that the SNPs cause depression, which in turn cause AD,” said Dr. Wingo.
 

One-way relationship

The researchers conducted the same analysis on 61 significant SNPs from the GWAS of AD but did not find evidence to conclude AD causes depression.

“We found genetic evidence supporting a causal role of depression in AD but not vice versa,” Dr. Wingo said.

In addition, the investigators identified 75 brain transcripts (messenger RNA) and 28 brain proteins regulated by the depression-predisposing genetic variants. Of these, 46 brain transcripts and seven proteins were significantly associated with at least one AD feature – for example, beta-amyloid, tau tangles, and cognitive trajectory.

“These findings support the notion that the depression risk variants contribute to AD via regulating expression of their corresponding transcripts in the brain,” the investigators wrote.

It is only recently that large enough studies have allowed researchers sufficient power to reach these conclusions, coinvestigator Thomas Wingo, MD, said in an interview.

These additional “insights” into the relationship between depression and AD might “motivate” clinicians more to screen for and treat depressive symptoms, Dr. Aliza Wingo noted.

The new results also have implications for developing therapeutics to treat depression, she said. “If we target the genes, the brain proteins, that are shared risk between depression and AD, the medications that target that gene might mitigate risk for AD later on.”

However, the investigators advised caution. “A lot of this is still unknown,” said Dr. Thomas Wingo.

For example, it is not clear whether successfully treating depression mitigates the eventual risk of dementia, which is “a very important topic of inquiry and one we continue to work on,” he said, adding that a significant number of patients do not respond well to existing antidepressants such as SSRIs.
 

Need for further research

Commenting on the findings, Claire Sexton, DPhil, director of scientific programs and outreach, Alzheimer’s Association, said the study contributes to the debate about whether depression increases risk for AD, whether AD increases risk for depression, or both.

“These newly published findings strengthen our understanding of the role of depression as a risk factor for Alzheimer’s dementia,” said Dr. Sexton, who was not involved with the research.

While experts do not yet fully understand the impact of treating depression on dementia risk, “the findings emphasize the importance of assessing mental health status, particularly depression, and getting it properly diagnosed and treated in a timely manner,” she said.

However, she agreed more research in this area is needed. “Importantly, these findings need replication in broader, more diverse study populations,” Dr. Sexton said.

A study funded by the Alzheimer’s Association may provide more information on the link between depression and AD. It will investigate whether machine learning, an advanced computer science technique, can better predict cognitive decline, compared with traditional methods.

Over a period of 6 months, researchers will collect smartphone conversations from 225 older adults with dementia, mild cognitive impairment, or no cognitive impairment. They will also have data from cognitive tests, brain scans, and biomarkers such as cerebrospinal fluid samples to study brain changes associated with AD.

The novel method of analysis should be able to identify subtle differences in speech quality to indicate which depressive symptoms an individual might be experiencing.

“The study could help us further understand the potential impact of depression in the risk of developing dementia,” said Dr. Sexton.

Dr. Aliza Wingo and Dr. Thomas Wingo reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Researchers have known for some time that depression is associated with Alzheimer’s disease (AD), but a causal link has been elusive. Now, using newly available data, they have uncovered genetic evidence of a causal role for depression in AD.

As depression typically affects those in early or midlife and dementia often occurs in later life, “it’s fascinating to see a connection between the two brain illnesses that manifest in different time windows,” coinvestigator Aliza P. Wingo, MD, associate professor of psychiatry and behavioral science, Emory University, Atlanta, said in an interview.

“If we can treat the depression early on, we may help reduce risk for dementia for our patients later in life,” Dr. Wingo said.

The findings were published online Dec. 16, 2021, in Biological Psychiatry.

Postmortem data

The investigators, who are all from the Emory University Center for Neurodegenerative Disease, wanted to clarify the genetic basis underlying the association between the established link between depression and dementia risk.

They used data from the largest and most recent genomewide association studies (GWAS). These included a 2019 analysis of depression among 807,553 individuals and a 2019 study of AD among 455,258 individuals, all of European ancestry. For sensitivity analyses, they used results from two additional AD GWAS.

The researchers also accessed postmortem brain samples from participants in the Religious Orders Study (ROS) and the Rush Memory and Aging Project (MAP). These participants were cognitively normal at enrollment, underwent annual clinical evaluations, and agreed to donate their brains.

They also assessed brain samples donated by participants in the Banner Sun Health Research Institute longitudinal study of healthy aging, Alzheimer’s, and Parkinson’s disease.

The brain samples allowed researchers to use deep brain proteomic data to help determine molecular links between depression and AD.

After quality control, the analysis included 8,356 proteins in 391 ROS/MAP participants and 7,854 proteins in 196 Banner participants.

Results showed a small but significant positive genetic correlation between depression and AD, suggesting the two conditions have a shared genetic basis.

The investigators also applied a framework called “Mendelian randomization” to determine causality between depression and AD.

After assessing the effect of 115 independent single-nucleotide polymorphisms (SNPs) from the GWAS of depression, they uncovered significant evidence “that the SNPs cause depression, which in turn cause AD,” said Dr. Wingo.
 

One-way relationship

The researchers conducted the same analysis on 61 significant SNPs from the GWAS of AD but did not find evidence to conclude AD causes depression.

“We found genetic evidence supporting a causal role of depression in AD but not vice versa,” Dr. Wingo said.

In addition, the investigators identified 75 brain transcripts (messenger RNA) and 28 brain proteins regulated by the depression-predisposing genetic variants. Of these, 46 brain transcripts and seven proteins were significantly associated with at least one AD feature – for example, beta-amyloid, tau tangles, and cognitive trajectory.

“These findings support the notion that the depression risk variants contribute to AD via regulating expression of their corresponding transcripts in the brain,” the investigators wrote.

It is only recently that large enough studies have allowed researchers sufficient power to reach these conclusions, coinvestigator Thomas Wingo, MD, said in an interview.

These additional “insights” into the relationship between depression and AD might “motivate” clinicians more to screen for and treat depressive symptoms, Dr. Aliza Wingo noted.

The new results also have implications for developing therapeutics to treat depression, she said. “If we target the genes, the brain proteins, that are shared risk between depression and AD, the medications that target that gene might mitigate risk for AD later on.”

However, the investigators advised caution. “A lot of this is still unknown,” said Dr. Thomas Wingo.

For example, it is not clear whether successfully treating depression mitigates the eventual risk of dementia, which is “a very important topic of inquiry and one we continue to work on,” he said, adding that a significant number of patients do not respond well to existing antidepressants such as SSRIs.
 

Need for further research

Commenting on the findings, Claire Sexton, DPhil, director of scientific programs and outreach, Alzheimer’s Association, said the study contributes to the debate about whether depression increases risk for AD, whether AD increases risk for depression, or both.

“These newly published findings strengthen our understanding of the role of depression as a risk factor for Alzheimer’s dementia,” said Dr. Sexton, who was not involved with the research.

While experts do not yet fully understand the impact of treating depression on dementia risk, “the findings emphasize the importance of assessing mental health status, particularly depression, and getting it properly diagnosed and treated in a timely manner,” she said.

However, she agreed more research in this area is needed. “Importantly, these findings need replication in broader, more diverse study populations,” Dr. Sexton said.

A study funded by the Alzheimer’s Association may provide more information on the link between depression and AD. It will investigate whether machine learning, an advanced computer science technique, can better predict cognitive decline, compared with traditional methods.

Over a period of 6 months, researchers will collect smartphone conversations from 225 older adults with dementia, mild cognitive impairment, or no cognitive impairment. They will also have data from cognitive tests, brain scans, and biomarkers such as cerebrospinal fluid samples to study brain changes associated with AD.

The novel method of analysis should be able to identify subtle differences in speech quality to indicate which depressive symptoms an individual might be experiencing.

“The study could help us further understand the potential impact of depression in the risk of developing dementia,” said Dr. Sexton.

Dr. Aliza Wingo and Dr. Thomas Wingo reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Researchers have known for some time that depression is associated with Alzheimer’s disease (AD), but a causal link has been elusive. Now, using newly available data, they have uncovered genetic evidence of a causal role for depression in AD.

As depression typically affects those in early or midlife and dementia often occurs in later life, “it’s fascinating to see a connection between the two brain illnesses that manifest in different time windows,” coinvestigator Aliza P. Wingo, MD, associate professor of psychiatry and behavioral science, Emory University, Atlanta, said in an interview.

“If we can treat the depression early on, we may help reduce risk for dementia for our patients later in life,” Dr. Wingo said.

The findings were published online Dec. 16, 2021, in Biological Psychiatry.

Postmortem data

The investigators, who are all from the Emory University Center for Neurodegenerative Disease, wanted to clarify the genetic basis underlying the association between the established link between depression and dementia risk.

They used data from the largest and most recent genomewide association studies (GWAS). These included a 2019 analysis of depression among 807,553 individuals and a 2019 study of AD among 455,258 individuals, all of European ancestry. For sensitivity analyses, they used results from two additional AD GWAS.

The researchers also accessed postmortem brain samples from participants in the Religious Orders Study (ROS) and the Rush Memory and Aging Project (MAP). These participants were cognitively normal at enrollment, underwent annual clinical evaluations, and agreed to donate their brains.

They also assessed brain samples donated by participants in the Banner Sun Health Research Institute longitudinal study of healthy aging, Alzheimer’s, and Parkinson’s disease.

The brain samples allowed researchers to use deep brain proteomic data to help determine molecular links between depression and AD.

After quality control, the analysis included 8,356 proteins in 391 ROS/MAP participants and 7,854 proteins in 196 Banner participants.

Results showed a small but significant positive genetic correlation between depression and AD, suggesting the two conditions have a shared genetic basis.

The investigators also applied a framework called “Mendelian randomization” to determine causality between depression and AD.

After assessing the effect of 115 independent single-nucleotide polymorphisms (SNPs) from the GWAS of depression, they uncovered significant evidence “that the SNPs cause depression, which in turn cause AD,” said Dr. Wingo.
 

One-way relationship

The researchers conducted the same analysis on 61 significant SNPs from the GWAS of AD but did not find evidence to conclude AD causes depression.

“We found genetic evidence supporting a causal role of depression in AD but not vice versa,” Dr. Wingo said.

In addition, the investigators identified 75 brain transcripts (messenger RNA) and 28 brain proteins regulated by the depression-predisposing genetic variants. Of these, 46 brain transcripts and seven proteins were significantly associated with at least one AD feature – for example, beta-amyloid, tau tangles, and cognitive trajectory.

“These findings support the notion that the depression risk variants contribute to AD via regulating expression of their corresponding transcripts in the brain,” the investigators wrote.

It is only recently that large enough studies have allowed researchers sufficient power to reach these conclusions, coinvestigator Thomas Wingo, MD, said in an interview.

These additional “insights” into the relationship between depression and AD might “motivate” clinicians more to screen for and treat depressive symptoms, Dr. Aliza Wingo noted.

The new results also have implications for developing therapeutics to treat depression, she said. “If we target the genes, the brain proteins, that are shared risk between depression and AD, the medications that target that gene might mitigate risk for AD later on.”

However, the investigators advised caution. “A lot of this is still unknown,” said Dr. Thomas Wingo.

For example, it is not clear whether successfully treating depression mitigates the eventual risk of dementia, which is “a very important topic of inquiry and one we continue to work on,” he said, adding that a significant number of patients do not respond well to existing antidepressants such as SSRIs.
 

Need for further research

Commenting on the findings, Claire Sexton, DPhil, director of scientific programs and outreach, Alzheimer’s Association, said the study contributes to the debate about whether depression increases risk for AD, whether AD increases risk for depression, or both.

“These newly published findings strengthen our understanding of the role of depression as a risk factor for Alzheimer’s dementia,” said Dr. Sexton, who was not involved with the research.

While experts do not yet fully understand the impact of treating depression on dementia risk, “the findings emphasize the importance of assessing mental health status, particularly depression, and getting it properly diagnosed and treated in a timely manner,” she said.

However, she agreed more research in this area is needed. “Importantly, these findings need replication in broader, more diverse study populations,” Dr. Sexton said.

A study funded by the Alzheimer’s Association may provide more information on the link between depression and AD. It will investigate whether machine learning, an advanced computer science technique, can better predict cognitive decline, compared with traditional methods.

Over a period of 6 months, researchers will collect smartphone conversations from 225 older adults with dementia, mild cognitive impairment, or no cognitive impairment. They will also have data from cognitive tests, brain scans, and biomarkers such as cerebrospinal fluid samples to study brain changes associated with AD.

The novel method of analysis should be able to identify subtle differences in speech quality to indicate which depressive symptoms an individual might be experiencing.

“The study could help us further understand the potential impact of depression in the risk of developing dementia,” said Dr. Sexton.

Dr. Aliza Wingo and Dr. Thomas Wingo reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.