Depressive Symptoms Could Lead to Diabetes in Elderly

Older adults who report a high degree of depressive symptoms are more likely to develop type 2 diabetes than are those without depressive symptoms, according to Mercedes R. Carnethon, Ph.D., of Northwestern University, Chicago, and her associates in the Cardiovascular Health Study.

Several studies have found an association between depressive symptoms or clinical depression and diabetes, but this is the first to examine the issue in a population of people over age 65, who have a high prevalence of both disorders, Dr. Carnethon and her associates said (Arch. Intern. Med. 2007;167:802–7).

The researchers assessed data on 4,681 participants in the Cardiovascular Health Study, which took place from 1989 to 1999. Depressive symptoms had been evaluated annually using the 10-item Center for Epidemiological Studies Depression Scale.

A minimum score of 0 for each item would indicate that the subject experienced that depressive symptom never or rarely, and a maximum score of 3 for each item would indicate that the subject experienced that symptom most of the time or always. Total scores of 8 or more points, out of a possible maximum of 30 points, were considered high.

Twenty percent of the participants had high depressive symptom scores on at least one occasion. The proportion of subjects who were overweight or obese–a factor that could potentially confound the association with diabetes–was similar across those who had low, intermediate, or high depressive symptom scores.

New-onset diabetes was determined by the subjects' use of insulin or oral diabetes medications and by fasting glucose levels that were measured on two occasions during follow-up. A total of 234 subjects developed diabetes.

A high number of depressive symptoms on a single occasion, a significant increase in such symptoms over time, and persistently high symptoms over time all were associated with an excess incidence of diabetes, the investigators said.

The strongest link with diabetes was found when depressive symptom scores rose by at least 5 points over time.

“These findings were present across demographic strata and persisted with statistical adjustment for known correlates of depression and diabetes, such as BMI [body mass index], physical activity, cigarette smoking, alcohol intake, and C-reactive protein level,” Dr. Carnethon and her associates said.

In summary, high depressive symptoms might be connected to the development of diabetes in older adults, and this association might not be attributable solely to adverse health behaviors or weight gain. “The pathophysiologic mechanism for this association remains unclear,” they said.

Inflammation is often proposed as a likely mechanism, because inflammatory markers are associated with both diabetes and depression. However, the findings of this study showed no attenuation of the link between the two disorders when the data were adjusted for C-reactive protein levels.

This suggests that “other biological mechanisms previously proposed, such as hypothalamic-pituitary-adrenal axis dysregulation and sympathetic nervous system stimulation, may be more salient,” they added.

Older adults who report a high degree of depressive symptoms are more likely to develop type 2 diabetes than are those without depressive symptoms, according to Mercedes R. Carnethon, Ph.D., of Northwestern University, Chicago, and her associates in the Cardiovascular Health Study.

Several studies have found an association between depressive symptoms or clinical depression and diabetes, but this is the first to examine the issue in a population of people over age 65, who have a high prevalence of both disorders, Dr. Carnethon and her associates said (Arch. Intern. Med. 2007;167:802–7).

The researchers assessed data on 4,681 participants in the Cardiovascular Health Study, which took place from 1989 to 1999. Depressive symptoms had been evaluated annually using the 10-item Center for Epidemiological Studies Depression Scale.

A minimum score of 0 for each item would indicate that the subject experienced that depressive symptom never or rarely, and a maximum score of 3 for each item would indicate that the subject experienced that symptom most of the time or always. Total scores of 8 or more points, out of a possible maximum of 30 points, were considered high.

Twenty percent of the participants had high depressive symptom scores on at least one occasion. The proportion of subjects who were overweight or obese–a factor that could potentially confound the association with diabetes–was similar across those who had low, intermediate, or high depressive symptom scores.

New-onset diabetes was determined by the subjects' use of insulin or oral diabetes medications and by fasting glucose levels that were measured on two occasions during follow-up. A total of 234 subjects developed diabetes.

A high number of depressive symptoms on a single occasion, a significant increase in such symptoms over time, and persistently high symptoms over time all were associated with an excess incidence of diabetes, the investigators said.

The strongest link with diabetes was found when depressive symptom scores rose by at least 5 points over time.

“These findings were present across demographic strata and persisted with statistical adjustment for known correlates of depression and diabetes, such as BMI [body mass index], physical activity, cigarette smoking, alcohol intake, and C-reactive protein level,” Dr. Carnethon and her associates said.

In summary, high depressive symptoms might be connected to the development of diabetes in older adults, and this association might not be attributable solely to adverse health behaviors or weight gain. “The pathophysiologic mechanism for this association remains unclear,” they said.

Inflammation is often proposed as a likely mechanism, because inflammatory markers are associated with both diabetes and depression. However, the findings of this study showed no attenuation of the link between the two disorders when the data were adjusted for C-reactive protein levels.

This suggests that “other biological mechanisms previously proposed, such as hypothalamic-pituitary-adrenal axis dysregulation and sympathetic nervous system stimulation, may be more salient,” they added.

Older adults who report a high degree of depressive symptoms are more likely to develop type 2 diabetes than are those without depressive symptoms, according to Mercedes R. Carnethon, Ph.D., of Northwestern University, Chicago, and her associates in the Cardiovascular Health Study.

Several studies have found an association between depressive symptoms or clinical depression and diabetes, but this is the first to examine the issue in a population of people over age 65, who have a high prevalence of both disorders, Dr. Carnethon and her associates said (Arch. Intern. Med. 2007;167:802–7).

The researchers assessed data on 4,681 participants in the Cardiovascular Health Study, which took place from 1989 to 1999. Depressive symptoms had been evaluated annually using the 10-item Center for Epidemiological Studies Depression Scale.

A minimum score of 0 for each item would indicate that the subject experienced that depressive symptom never or rarely, and a maximum score of 3 for each item would indicate that the subject experienced that symptom most of the time or always. Total scores of 8 or more points, out of a possible maximum of 30 points, were considered high.

Twenty percent of the participants had high depressive symptom scores on at least one occasion. The proportion of subjects who were overweight or obese–a factor that could potentially confound the association with diabetes–was similar across those who had low, intermediate, or high depressive symptom scores.

New-onset diabetes was determined by the subjects' use of insulin or oral diabetes medications and by fasting glucose levels that were measured on two occasions during follow-up. A total of 234 subjects developed diabetes.

A high number of depressive symptoms on a single occasion, a significant increase in such symptoms over time, and persistently high symptoms over time all were associated with an excess incidence of diabetes, the investigators said.

The strongest link with diabetes was found when depressive symptom scores rose by at least 5 points over time.

“These findings were present across demographic strata and persisted with statistical adjustment for known correlates of depression and diabetes, such as BMI [body mass index], physical activity, cigarette smoking, alcohol intake, and C-reactive protein level,” Dr. Carnethon and her associates said.

In summary, high depressive symptoms might be connected to the development of diabetes in older adults, and this association might not be attributable solely to adverse health behaviors or weight gain. “The pathophysiologic mechanism for this association remains unclear,” they said.

Inflammation is often proposed as a likely mechanism, because inflammatory markers are associated with both diabetes and depression. However, the findings of this study showed no attenuation of the link between the two disorders when the data were adjusted for C-reactive protein levels.

This suggests that “other biological mechanisms previously proposed, such as hypothalamic-pituitary-adrenal axis dysregulation and sympathetic nervous system stimulation, may be more salient,” they added.