Pulmonary Health Hub

Electronic cigarettes (e-cigarettes) have become increasingly popular over the last decade. Although they are perceived by many to be safer than traditional cigarettes, many of the devices still contain nicotine, and inhaling their vapors exposes users to toxic substances, including lead, cadmium, and nickel—heavy metals that are associated with significant health problems.¹ (For more on how e-cigarettes work, see “Cigarettes vs e-cigarettes: How does the experience (and cost) compare?”)

In addition, many people use e-cigarettes as a means to stop smoking, but few who do so achieve abstinence.^2,3 They frequently end up utilizing both, increasing their health risks by exposing themselves to the dangers of 2 products instead of one.¹

Further complicating the issue is that the manufacture and distribution of e-cigarettes has not been well regulated. Without regulation, there is no way to know with certainty how much nicotine the devices contain and what else is in them.

Things, however, are changing. The Food and Drug Administration (FDA) recently announced that e-cigarettes and other tobacco products like cigars and hookahs will now be regulated in the same way the government regulates tobacco cigarettes and smokeless tobacco.⁴ The rule will not take effect immediately because companies requested time to comply, but once it is enacted, packaging will be required to list what the products contain, among other changes.

Keeping up on the latest information on e-cigarettes is now—and will continue to be—important as family physicians are increasingly asked about them. What follows is a review of what we know about their potential risks.

© 2016 iStock

A nicotine system developed by a pharmacist

E-cigarettes, or electronic nicotine delivery systems, were patented in 2003 by a Chinese pharmacist.⁵ Since their introduction to North America and Europe in 2007, the devices have become known by over 400 different brand names.⁶ Consumption among adults doubled by 2012, and by 2014, about 4% of US adults used e-cigarettes every day or some days.⁷ Many of them are dual users of tobacco and electronic cigarettes. In fact, Jenkins and colleagues reports in this issue of JFP (see "E-cigarettes: Who's using them and why?") that over half of cigarette smokers (52%) in their study use e-cigarettes, usually to either lower their cigarette consumption or aid in smoking cessation. (Throughout this article, we will use “cigarettes” and “smoking” to refer to the use of traditional tobacco cigarettes.)

In addition to concern over an increase in use among the general population, there is significant concern about the increase in e-cigarette use among US middle and high school students.^1,8,9 In 2015, e-cigarettes were the most commonly used smoking product among middle and high school students, with 620,000 middle school students and nearly 2.4 million high school students using the battery-powered devices in the past 30 days.¹⁰

Many factors have contributed to the growing popularity of e-cigarettes.

• Perceived safety. With tobacco’s dangers so thoroughly documented, many advertising campaigns tout e-cigarettes as less dangerous than conventional cigarettes in terms of their ability to cause cardiac and lung diseases and low birth weights. This is largely because e-cigarettes do not produce the combustion products of tar, ash, or carbon monoxide. In addition, many consumers are mistakenly less fearful about the nicotine added to many e-cigarettes.
• Expectation that it helps smokers quit. Many smokers view e-cigarettes as an aid to smoking cessation.⁶ In fact, testimonials of efficacy in tobacco cessation abound in promotional materials and on the Web, and e-cigarettes are recommended by some physicians as a means to quit or lessen smoking of tobacco cigarettes.¹¹
• Wide availability and opportunities for use. The use of electronic nicotine delivery devices is sometimes permitted in places where smoking of conventional cigarettes is banned, although rules vary widely in different parts of the country. In addition, e-cigarettes are readily available for purchase on the Internet without age verification.
• Extensive advertising. There are increasing concerns that advertising campaigns unduly target adolescents, young adults, and women.^12-155 In addition to advertising, the media and social influences play significant roles in young people’s experimentation with “vaping,” the term for inhaling electronic cigarette aerosols.^14,15
• Regulation, legislation remain controversial. Currently, e-cigarettes are not required to be tested before marketing,¹⁶ but that may change with the FDA’s new regulations. The British National Public Health body, Public Health England, has documented public health benefits of e-cigarettes when used as a way to quit smoking, and provides evidence that the devices are less dangerous than traditional cigarettes.¹⁷ But this issue and public policy are the subject of ongoing debate. In 2015, the United Kingdom made it illegal to sell e-cigarettes or e-liquids to people younger than 18 years of age and urged child-proof packaging.

What’s “in” an e-cigarette—and are the ingredients toxic?

Because e-cigarettes are relatively new to the global marketplace, little research exists regarding the long-term effects and safety of their use, especially among habitual users.

Vapor/refills. E-liquids may contain a variety of substances because they have been largely unregulated, but they generally include some combination of nicotine, propylene glycol, glycerin, and flavorings. In fact, up to 7000 flavors are available,⁶ including such kid-friendly flavors as chocolate, cherry crush, and bubble gum.

Since many individuals continue to use traditional and electronic cigarettes, they end up in double jeopardy of toxicity through exposure to the dangers of both.

When the refills do contain nicotine, users generally derive less of the substance from the electronic devices than they do from a conventional cigarette. Researchers found that individual puffs from an e-cigarette contained 0 to 35 µg nicotine per puff.^1,18 Assuming an amount at the high end of the spectrum (30 µg nicotine), it would take about 30 puffs of an e-cigarette to derive the same amount of nicotine (1 mg) typically delivered by a conventional cigarette.

The chemical make-up of the vapor and the biologic effects on animal models have been investigated using 42 different liquid refills.^19,20 All contained potentially harmful compounds, but the levels were within exposure limits authorized by the FDA. These potentially dangerous chemicals include the known toxins formaldehyde, acrolein, and hydrocarbons.²⁰

An inflammatory response to the inhalation of the vapors was demonstrated in mouse lungs; exposure to e-cigarette aerosols reduced lung glutathione—an important enzyme in maintaining oxidation-reduction balance—to a degree similar to that of cigarette smoke exposure.²⁰ Less of the enzyme facilitates increased pulmonary inflammation.

In addition, human lung cells release pro-inflammatory cytokines when exposed to e-cigarette aerosols.²⁰ Other health risks include:

Harm to indoor air quality/secondhand exposure. Even though e-cigarettes do not emit smoke, bystanders are exposed to the aerosol or vapor exhaled by the user, and researchers have found varying levels of such substances as formaldehyde, acetaldehyde, isoprene, acetic acid, acetone, propanol, propylene glycol, and nicotine in the air. However, it is unclear at this time whether the ultra-fine particles in the e-cigarette vapor have health effects commensurate with the emissions of conventional cigarettes.^1,21,22

Cartridge refill ingestion by children. Accidental nicotine poisonings, particularly among children drawn to the colors, flavors, and scents of the e-liquids, have been problematic. In 2014, for example, over 3500 exposures occurred and more than half of those were in children younger than 6 years of age. (Exposure is defined as contact with the substance in some way including ingestion, inhalation, absorption by the skin/eyes, etc; not all exposures are poisonings or overdoses).²³ Although incidence has tapered off somewhat, the American Association of Poison Control Centers reports that there were 623 exposures across all age groups between January 1, 2016 and April 30, 2016.²³

Many people use e-cigarettes as a means to stop smoking, but few who do so achieve abstinence.

Environmental impact of discarded e-cigarettes. Discarded e-cigarettes filling our landfills is a new and emerging public health concern. Their batteries, as do all batteries, pollute the land and water and have the potential to leach lead into the environment.²⁴ Similarly, incompletely used liquid cartridges and refills may contain nicotine and heavy metals, which add to these risks.²⁴

Explosions. Fires and explosions have been documented with e-cigarette use, mostly due to malfunctioning lithium-ion batteries.²⁵ Thermal injuries to the face and hands can be significant.

Heavy metals. The presence of lead, cadmium, and nickel in inhaled e-cigarette vapor is another area of significant concern, particularly for younger people who might have long-term exposure.¹ All 3 heavy metals are known to be toxic to humans, and safe levels of inhalation have not been established.

Inhalation and/or ingestion of lead, in particular, can cause severe neurologic damage, especially to the developing brains of children.²⁶ Lead also results in hematologic dysfunction. Because of the risks associated with inhalation of this heavy metal, the substance was removed from gasoline years ago.

Inhaled cadmium induces kidney, liver, bone, and respiratory tract pathology²⁷ and can cause organ failure, hypertension, anemias, fractures, osteoporosis, and/or osteomalacia.²⁸ And inhaling nickel produces an inflammatory pulmonary reaction.²⁹

Pregnancy/lactation. Since no clear evidence exists on the safety of e-cigarette use during pregnancy, women should avoid exposure to these vapors during the entire perinatal period. Similarly, the effects of e-cigarettes on infants who are breastfeeding are not established. Pregnant and breastfeeding women should not replace cigarettes with e-cigarettes.^30,31 For pregnant women who smoke, the US Preventive Services Task Force (USPSTF) advises using only behavioral methods to stop cigarette use.³² And until more information becomes available, exposing infants and young children to e-cigarette vapor during breastfeeding is not recommended.

On the flip side, without tobacco, tar, ash, or carbon monoxide, e-cigarettes may have some advantages when compared with the use of traditional cigarettes, but that has not been substantiated.

Don’t substitute one form of nicotine for another

The presence of lead, cadmium, and nickel in inhaled e-cigarette vapor is an area of significant concern.

The USPSTF has not determined the benefit-to-harm ratio of using e-cigarettes as a smoking cessation aid, but recommends prescribing behavioral techniques and/or pharmacologic alternatives instead.³² Because the devices have been promoted as an aid to smoking cessation, intention to quit using tobacco products is a reason often stated for utilizing e-cigarettes.^2,33,34 Indeed, use of e-cigarettes is much more likely among those who already utilize tobacco products.^35-37

At least one study reports that e-cigarettes have efficacy similar to nicotine patches in achieving smoking abstinence among smokers who want to quit.³⁸ Former smokers who used e-cigarettes to quit smoking reported fewer withdrawal symptoms than those who used nicotine skin patches.³⁹ In addition, former smokers were more likely to endorse e-cigarettes than nicotine patches as a tobacco cigarette cessation aid. Significant reduction in tobacco smoke exposure has been demonstrated in dual users of tobacco and electronic cigarettes;^40,41 however, both of these nicotine delivery systems sustain nicotine addiction.

Despite many ongoing studies to determine if e-cigarettes are useful as a smoking cessation aid, the results vary widely and are inconclusive at this time.⁴²

E-cigarettes do not increase long-term tobacco abstinence

Contrary to popular belief, research shows that e-cigarette use among smokers is not associated with long-term tobacco abstinence.¹ E-cigarette users, however, may make more attempts to quit smoking compared with smokers not using them.⁴³ In addition, even though there is some evidence that e-cigarettes help smokers reduce the number of cigarettes smoked per day, simply reducing the daily number of cigarettes does not equate with safety.⁴⁴ Smoking just one to 4 cigarettes per day poses 3 times the risk of myocardial infarction and lung cancer compared with not smoking.⁴⁴ And since many individuals continue to use traditional and electronic cigarettes, they end up in double jeopardy of toxicity through exposure to the dangers of both.

A gateway to other substances of abuse?

Pregnant and breastfeeding women should not replace tobacco cigarettes with e-cigarettes.

There is also fear that nicotine exposure via e-cigarettes, especially in young people, serves as a “gateway” to tobacco consumption and other substance abuses, and increases the risk for nicotine addiction.³⁴ Such nicotine-induced effects are a result of changes in brain chemistry, and have been documented in humans and animals.³⁴

These concerns about negative health consequences, combined with the fact that e-cigarettes are undocumented as a smoking cessation aid, add urgency to the need for legislative and regulatory actions that hopefully can curb all nicotine exposures, particularly for our nation’s youth. In the meantime, it is important for physicians to advise patients—and the public—about the risks of e-cigarettes and the importance of quitting all forms of nicotine inhalation because nicotine—regardless of how it is delivered—is still an addictive drug.

CORRESPONDENCE
Steven Lippmann, MD, University of Louisville School of Medicine, 401 E. Chestnut Street, Suite 610, Louisville, KY 40202; [email protected].

Electronic cigarettes (e-cigarettes) have become increasingly popular over the last decade. Although they are perceived by many to be safer than traditional cigarettes, many of the devices still contain nicotine, and inhaling their vapors exposes users to toxic substances, including lead, cadmium, and nickel—heavy metals that are associated with significant health problems.¹ (For more on how e-cigarettes work, see “Cigarettes vs e-cigarettes: How does the experience (and cost) compare?”)

In addition, many people use e-cigarettes as a means to stop smoking, but few who do so achieve abstinence.^2,3 They frequently end up utilizing both, increasing their health risks by exposing themselves to the dangers of 2 products instead of one.¹

Further complicating the issue is that the manufacture and distribution of e-cigarettes has not been well regulated. Without regulation, there is no way to know with certainty how much nicotine the devices contain and what else is in them.

Things, however, are changing. The Food and Drug Administration (FDA) recently announced that e-cigarettes and other tobacco products like cigars and hookahs will now be regulated in the same way the government regulates tobacco cigarettes and smokeless tobacco.⁴ The rule will not take effect immediately because companies requested time to comply, but once it is enacted, packaging will be required to list what the products contain, among other changes.

Keeping up on the latest information on e-cigarettes is now—and will continue to be—important as family physicians are increasingly asked about them. What follows is a review of what we know about their potential risks.

© 2016 iStock

A nicotine system developed by a pharmacist

E-cigarettes, or electronic nicotine delivery systems, were patented in 2003 by a Chinese pharmacist.⁵ Since their introduction to North America and Europe in 2007, the devices have become known by over 400 different brand names.⁶ Consumption among adults doubled by 2012, and by 2014, about 4% of US adults used e-cigarettes every day or some days.⁷ Many of them are dual users of tobacco and electronic cigarettes. In fact, Jenkins and colleagues reports in this issue of JFP (see "E-cigarettes: Who's using them and why?") that over half of cigarette smokers (52%) in their study use e-cigarettes, usually to either lower their cigarette consumption or aid in smoking cessation. (Throughout this article, we will use “cigarettes” and “smoking” to refer to the use of traditional tobacco cigarettes.)

In addition to concern over an increase in use among the general population, there is significant concern about the increase in e-cigarette use among US middle and high school students.^1,8,9 In 2015, e-cigarettes were the most commonly used smoking product among middle and high school students, with 620,000 middle school students and nearly 2.4 million high school students using the battery-powered devices in the past 30 days.¹⁰

Many factors have contributed to the growing popularity of e-cigarettes.

• Perceived safety. With tobacco’s dangers so thoroughly documented, many advertising campaigns tout e-cigarettes as less dangerous than conventional cigarettes in terms of their ability to cause cardiac and lung diseases and low birth weights. This is largely because e-cigarettes do not produce the combustion products of tar, ash, or carbon monoxide. In addition, many consumers are mistakenly less fearful about the nicotine added to many e-cigarettes.
• Expectation that it helps smokers quit. Many smokers view e-cigarettes as an aid to smoking cessation.⁶ In fact, testimonials of efficacy in tobacco cessation abound in promotional materials and on the Web, and e-cigarettes are recommended by some physicians as a means to quit or lessen smoking of tobacco cigarettes.¹¹
• Wide availability and opportunities for use. The use of electronic nicotine delivery devices is sometimes permitted in places where smoking of conventional cigarettes is banned, although rules vary widely in different parts of the country. In addition, e-cigarettes are readily available for purchase on the Internet without age verification.
• Extensive advertising. There are increasing concerns that advertising campaigns unduly target adolescents, young adults, and women.^12-155 In addition to advertising, the media and social influences play significant roles in young people’s experimentation with “vaping,” the term for inhaling electronic cigarette aerosols.^14,15
• Regulation, legislation remain controversial. Currently, e-cigarettes are not required to be tested before marketing,¹⁶ but that may change with the FDA’s new regulations. The British National Public Health body, Public Health England, has documented public health benefits of e-cigarettes when used as a way to quit smoking, and provides evidence that the devices are less dangerous than traditional cigarettes.¹⁷ But this issue and public policy are the subject of ongoing debate. In 2015, the United Kingdom made it illegal to sell e-cigarettes or e-liquids to people younger than 18 years of age and urged child-proof packaging.

What’s “in” an e-cigarette—and are the ingredients toxic?

Because e-cigarettes are relatively new to the global marketplace, little research exists regarding the long-term effects and safety of their use, especially among habitual users.

Vapor/refills. E-liquids may contain a variety of substances because they have been largely unregulated, but they generally include some combination of nicotine, propylene glycol, glycerin, and flavorings. In fact, up to 7000 flavors are available,⁶ including such kid-friendly flavors as chocolate, cherry crush, and bubble gum.

Since many individuals continue to use traditional and electronic cigarettes, they end up in double jeopardy of toxicity through exposure to the dangers of both.

When the refills do contain nicotine, users generally derive less of the substance from the electronic devices than they do from a conventional cigarette. Researchers found that individual puffs from an e-cigarette contained 0 to 35 µg nicotine per puff.^1,18 Assuming an amount at the high end of the spectrum (30 µg nicotine), it would take about 30 puffs of an e-cigarette to derive the same amount of nicotine (1 mg) typically delivered by a conventional cigarette.

The chemical make-up of the vapor and the biologic effects on animal models have been investigated using 42 different liquid refills.^19,20 All contained potentially harmful compounds, but the levels were within exposure limits authorized by the FDA. These potentially dangerous chemicals include the known toxins formaldehyde, acrolein, and hydrocarbons.²⁰

An inflammatory response to the inhalation of the vapors was demonstrated in mouse lungs; exposure to e-cigarette aerosols reduced lung glutathione—an important enzyme in maintaining oxidation-reduction balance—to a degree similar to that of cigarette smoke exposure.²⁰ Less of the enzyme facilitates increased pulmonary inflammation.

In addition, human lung cells release pro-inflammatory cytokines when exposed to e-cigarette aerosols.²⁰ Other health risks include:

Harm to indoor air quality/secondhand exposure. Even though e-cigarettes do not emit smoke, bystanders are exposed to the aerosol or vapor exhaled by the user, and researchers have found varying levels of such substances as formaldehyde, acetaldehyde, isoprene, acetic acid, acetone, propanol, propylene glycol, and nicotine in the air. However, it is unclear at this time whether the ultra-fine particles in the e-cigarette vapor have health effects commensurate with the emissions of conventional cigarettes.^1,21,22

Cartridge refill ingestion by children. Accidental nicotine poisonings, particularly among children drawn to the colors, flavors, and scents of the e-liquids, have been problematic. In 2014, for example, over 3500 exposures occurred and more than half of those were in children younger than 6 years of age. (Exposure is defined as contact with the substance in some way including ingestion, inhalation, absorption by the skin/eyes, etc; not all exposures are poisonings or overdoses).²³ Although incidence has tapered off somewhat, the American Association of Poison Control Centers reports that there were 623 exposures across all age groups between January 1, 2016 and April 30, 2016.²³

Many people use e-cigarettes as a means to stop smoking, but few who do so achieve abstinence.

Environmental impact of discarded e-cigarettes. Discarded e-cigarettes filling our landfills is a new and emerging public health concern. Their batteries, as do all batteries, pollute the land and water and have the potential to leach lead into the environment.²⁴ Similarly, incompletely used liquid cartridges and refills may contain nicotine and heavy metals, which add to these risks.²⁴

Explosions. Fires and explosions have been documented with e-cigarette use, mostly due to malfunctioning lithium-ion batteries.²⁵ Thermal injuries to the face and hands can be significant.

Heavy metals. The presence of lead, cadmium, and nickel in inhaled e-cigarette vapor is another area of significant concern, particularly for younger people who might have long-term exposure.¹ All 3 heavy metals are known to be toxic to humans, and safe levels of inhalation have not been established.

Inhalation and/or ingestion of lead, in particular, can cause severe neurologic damage, especially to the developing brains of children.²⁶ Lead also results in hematologic dysfunction. Because of the risks associated with inhalation of this heavy metal, the substance was removed from gasoline years ago.

Inhaled cadmium induces kidney, liver, bone, and respiratory tract pathology²⁷ and can cause organ failure, hypertension, anemias, fractures, osteoporosis, and/or osteomalacia.²⁸ And inhaling nickel produces an inflammatory pulmonary reaction.²⁹

Pregnancy/lactation. Since no clear evidence exists on the safety of e-cigarette use during pregnancy, women should avoid exposure to these vapors during the entire perinatal period. Similarly, the effects of e-cigarettes on infants who are breastfeeding are not established. Pregnant and breastfeeding women should not replace cigarettes with e-cigarettes.^30,31 For pregnant women who smoke, the US Preventive Services Task Force (USPSTF) advises using only behavioral methods to stop cigarette use.³² And until more information becomes available, exposing infants and young children to e-cigarette vapor during breastfeeding is not recommended.

On the flip side, without tobacco, tar, ash, or carbon monoxide, e-cigarettes may have some advantages when compared with the use of traditional cigarettes, but that has not been substantiated.

Don’t substitute one form of nicotine for another

The presence of lead, cadmium, and nickel in inhaled e-cigarette vapor is an area of significant concern.

The USPSTF has not determined the benefit-to-harm ratio of using e-cigarettes as a smoking cessation aid, but recommends prescribing behavioral techniques and/or pharmacologic alternatives instead.³² Because the devices have been promoted as an aid to smoking cessation, intention to quit using tobacco products is a reason often stated for utilizing e-cigarettes.^2,33,34 Indeed, use of e-cigarettes is much more likely among those who already utilize tobacco products.^35-37

At least one study reports that e-cigarettes have efficacy similar to nicotine patches in achieving smoking abstinence among smokers who want to quit.³⁸ Former smokers who used e-cigarettes to quit smoking reported fewer withdrawal symptoms than those who used nicotine skin patches.³⁹ In addition, former smokers were more likely to endorse e-cigarettes than nicotine patches as a tobacco cigarette cessation aid. Significant reduction in tobacco smoke exposure has been demonstrated in dual users of tobacco and electronic cigarettes;^40,41 however, both of these nicotine delivery systems sustain nicotine addiction.

Despite many ongoing studies to determine if e-cigarettes are useful as a smoking cessation aid, the results vary widely and are inconclusive at this time.⁴²

E-cigarettes do not increase long-term tobacco abstinence

Contrary to popular belief, research shows that e-cigarette use among smokers is not associated with long-term tobacco abstinence.¹ E-cigarette users, however, may make more attempts to quit smoking compared with smokers not using them.⁴³ In addition, even though there is some evidence that e-cigarettes help smokers reduce the number of cigarettes smoked per day, simply reducing the daily number of cigarettes does not equate with safety.⁴⁴ Smoking just one to 4 cigarettes per day poses 3 times the risk of myocardial infarction and lung cancer compared with not smoking.⁴⁴ And since many individuals continue to use traditional and electronic cigarettes, they end up in double jeopardy of toxicity through exposure to the dangers of both.

A gateway to other substances of abuse?

Pregnant and breastfeeding women should not replace tobacco cigarettes with e-cigarettes.

There is also fear that nicotine exposure via e-cigarettes, especially in young people, serves as a “gateway” to tobacco consumption and other substance abuses, and increases the risk for nicotine addiction.³⁴ Such nicotine-induced effects are a result of changes in brain chemistry, and have been documented in humans and animals.³⁴

These concerns about negative health consequences, combined with the fact that e-cigarettes are undocumented as a smoking cessation aid, add urgency to the need for legislative and regulatory actions that hopefully can curb all nicotine exposures, particularly for our nation’s youth. In the meantime, it is important for physicians to advise patients—and the public—about the risks of e-cigarettes and the importance of quitting all forms of nicotine inhalation because nicotine—regardless of how it is delivered—is still an addictive drug.

CORRESPONDENCE
Steven Lippmann, MD, University of Louisville School of Medicine, 401 E. Chestnut Street, Suite 610, Louisville, KY 40202; [email protected].

Electronic cigarettes (e-cigarettes) have become increasingly popular over the last decade. Although they are perceived by many to be safer than traditional cigarettes, many of the devices still contain nicotine, and inhaling their vapors exposes users to toxic substances, including lead, cadmium, and nickel—heavy metals that are associated with significant health problems.¹ (For more on how e-cigarettes work, see “Cigarettes vs e-cigarettes: How does the experience (and cost) compare?”)

In addition, many people use e-cigarettes as a means to stop smoking, but few who do so achieve abstinence.^2,3 They frequently end up utilizing both, increasing their health risks by exposing themselves to the dangers of 2 products instead of one.¹

Further complicating the issue is that the manufacture and distribution of e-cigarettes has not been well regulated. Without regulation, there is no way to know with certainty how much nicotine the devices contain and what else is in them.

Things, however, are changing. The Food and Drug Administration (FDA) recently announced that e-cigarettes and other tobacco products like cigars and hookahs will now be regulated in the same way the government regulates tobacco cigarettes and smokeless tobacco.⁴ The rule will not take effect immediately because companies requested time to comply, but once it is enacted, packaging will be required to list what the products contain, among other changes.

Keeping up on the latest information on e-cigarettes is now—and will continue to be—important as family physicians are increasingly asked about them. What follows is a review of what we know about their potential risks.

© 2016 iStock

A nicotine system developed by a pharmacist

E-cigarettes, or electronic nicotine delivery systems, were patented in 2003 by a Chinese pharmacist.⁵ Since their introduction to North America and Europe in 2007, the devices have become known by over 400 different brand names.⁶ Consumption among adults doubled by 2012, and by 2014, about 4% of US adults used e-cigarettes every day or some days.⁷ Many of them are dual users of tobacco and electronic cigarettes. In fact, Jenkins and colleagues reports in this issue of JFP (see "E-cigarettes: Who's using them and why?") that over half of cigarette smokers (52%) in their study use e-cigarettes, usually to either lower their cigarette consumption or aid in smoking cessation. (Throughout this article, we will use “cigarettes” and “smoking” to refer to the use of traditional tobacco cigarettes.)

In addition to concern over an increase in use among the general population, there is significant concern about the increase in e-cigarette use among US middle and high school students.^1,8,9 In 2015, e-cigarettes were the most commonly used smoking product among middle and high school students, with 620,000 middle school students and nearly 2.4 million high school students using the battery-powered devices in the past 30 days.¹⁰

Many factors have contributed to the growing popularity of e-cigarettes.

• Perceived safety. With tobacco’s dangers so thoroughly documented, many advertising campaigns tout e-cigarettes as less dangerous than conventional cigarettes in terms of their ability to cause cardiac and lung diseases and low birth weights. This is largely because e-cigarettes do not produce the combustion products of tar, ash, or carbon monoxide. In addition, many consumers are mistakenly less fearful about the nicotine added to many e-cigarettes.
• Expectation that it helps smokers quit. Many smokers view e-cigarettes as an aid to smoking cessation.⁶ In fact, testimonials of efficacy in tobacco cessation abound in promotional materials and on the Web, and e-cigarettes are recommended by some physicians as a means to quit or lessen smoking of tobacco cigarettes.¹¹
• Wide availability and opportunities for use. The use of electronic nicotine delivery devices is sometimes permitted in places where smoking of conventional cigarettes is banned, although rules vary widely in different parts of the country. In addition, e-cigarettes are readily available for purchase on the Internet without age verification.
• Extensive advertising. There are increasing concerns that advertising campaigns unduly target adolescents, young adults, and women.^12-155 In addition to advertising, the media and social influences play significant roles in young people’s experimentation with “vaping,” the term for inhaling electronic cigarette aerosols.^14,15
• Regulation, legislation remain controversial. Currently, e-cigarettes are not required to be tested before marketing,¹⁶ but that may change with the FDA’s new regulations. The British National Public Health body, Public Health England, has documented public health benefits of e-cigarettes when used as a way to quit smoking, and provides evidence that the devices are less dangerous than traditional cigarettes.¹⁷ But this issue and public policy are the subject of ongoing debate. In 2015, the United Kingdom made it illegal to sell e-cigarettes or e-liquids to people younger than 18 years of age and urged child-proof packaging.

What’s “in” an e-cigarette—and are the ingredients toxic?

Because e-cigarettes are relatively new to the global marketplace, little research exists regarding the long-term effects and safety of their use, especially among habitual users.

Vapor/refills. E-liquids may contain a variety of substances because they have been largely unregulated, but they generally include some combination of nicotine, propylene glycol, glycerin, and flavorings. In fact, up to 7000 flavors are available,⁶ including such kid-friendly flavors as chocolate, cherry crush, and bubble gum.

Since many individuals continue to use traditional and electronic cigarettes, they end up in double jeopardy of toxicity through exposure to the dangers of both.

When the refills do contain nicotine, users generally derive less of the substance from the electronic devices than they do from a conventional cigarette. Researchers found that individual puffs from an e-cigarette contained 0 to 35 µg nicotine per puff.^1,18 Assuming an amount at the high end of the spectrum (30 µg nicotine), it would take about 30 puffs of an e-cigarette to derive the same amount of nicotine (1 mg) typically delivered by a conventional cigarette.

The chemical make-up of the vapor and the biologic effects on animal models have been investigated using 42 different liquid refills.^19,20 All contained potentially harmful compounds, but the levels were within exposure limits authorized by the FDA. These potentially dangerous chemicals include the known toxins formaldehyde, acrolein, and hydrocarbons.²⁰

An inflammatory response to the inhalation of the vapors was demonstrated in mouse lungs; exposure to e-cigarette aerosols reduced lung glutathione—an important enzyme in maintaining oxidation-reduction balance—to a degree similar to that of cigarette smoke exposure.²⁰ Less of the enzyme facilitates increased pulmonary inflammation.

In addition, human lung cells release pro-inflammatory cytokines when exposed to e-cigarette aerosols.²⁰ Other health risks include:

Harm to indoor air quality/secondhand exposure. Even though e-cigarettes do not emit smoke, bystanders are exposed to the aerosol or vapor exhaled by the user, and researchers have found varying levels of such substances as formaldehyde, acetaldehyde, isoprene, acetic acid, acetone, propanol, propylene glycol, and nicotine in the air. However, it is unclear at this time whether the ultra-fine particles in the e-cigarette vapor have health effects commensurate with the emissions of conventional cigarettes.^1,21,22

Cartridge refill ingestion by children. Accidental nicotine poisonings, particularly among children drawn to the colors, flavors, and scents of the e-liquids, have been problematic. In 2014, for example, over 3500 exposures occurred and more than half of those were in children younger than 6 years of age. (Exposure is defined as contact with the substance in some way including ingestion, inhalation, absorption by the skin/eyes, etc; not all exposures are poisonings or overdoses).²³ Although incidence has tapered off somewhat, the American Association of Poison Control Centers reports that there were 623 exposures across all age groups between January 1, 2016 and April 30, 2016.²³

Many people use e-cigarettes as a means to stop smoking, but few who do so achieve abstinence.

Environmental impact of discarded e-cigarettes. Discarded e-cigarettes filling our landfills is a new and emerging public health concern. Their batteries, as do all batteries, pollute the land and water and have the potential to leach lead into the environment.²⁴ Similarly, incompletely used liquid cartridges and refills may contain nicotine and heavy metals, which add to these risks.²⁴

Explosions. Fires and explosions have been documented with e-cigarette use, mostly due to malfunctioning lithium-ion batteries.²⁵ Thermal injuries to the face and hands can be significant.

Heavy metals. The presence of lead, cadmium, and nickel in inhaled e-cigarette vapor is another area of significant concern, particularly for younger people who might have long-term exposure.¹ All 3 heavy metals are known to be toxic to humans, and safe levels of inhalation have not been established.

Inhalation and/or ingestion of lead, in particular, can cause severe neurologic damage, especially to the developing brains of children.²⁶ Lead also results in hematologic dysfunction. Because of the risks associated with inhalation of this heavy metal, the substance was removed from gasoline years ago.

Inhaled cadmium induces kidney, liver, bone, and respiratory tract pathology²⁷ and can cause organ failure, hypertension, anemias, fractures, osteoporosis, and/or osteomalacia.²⁸ And inhaling nickel produces an inflammatory pulmonary reaction.²⁹

Pregnancy/lactation. Since no clear evidence exists on the safety of e-cigarette use during pregnancy, women should avoid exposure to these vapors during the entire perinatal period. Similarly, the effects of e-cigarettes on infants who are breastfeeding are not established. Pregnant and breastfeeding women should not replace cigarettes with e-cigarettes.^30,31 For pregnant women who smoke, the US Preventive Services Task Force (USPSTF) advises using only behavioral methods to stop cigarette use.³² And until more information becomes available, exposing infants and young children to e-cigarette vapor during breastfeeding is not recommended.

On the flip side, without tobacco, tar, ash, or carbon monoxide, e-cigarettes may have some advantages when compared with the use of traditional cigarettes, but that has not been substantiated.

Don’t substitute one form of nicotine for another

The presence of lead, cadmium, and nickel in inhaled e-cigarette vapor is an area of significant concern.

The USPSTF has not determined the benefit-to-harm ratio of using e-cigarettes as a smoking cessation aid, but recommends prescribing behavioral techniques and/or pharmacologic alternatives instead.³² Because the devices have been promoted as an aid to smoking cessation, intention to quit using tobacco products is a reason often stated for utilizing e-cigarettes.^2,33,34 Indeed, use of e-cigarettes is much more likely among those who already utilize tobacco products.^35-37

At least one study reports that e-cigarettes have efficacy similar to nicotine patches in achieving smoking abstinence among smokers who want to quit.³⁸ Former smokers who used e-cigarettes to quit smoking reported fewer withdrawal symptoms than those who used nicotine skin patches.³⁹ In addition, former smokers were more likely to endorse e-cigarettes than nicotine patches as a tobacco cigarette cessation aid. Significant reduction in tobacco smoke exposure has been demonstrated in dual users of tobacco and electronic cigarettes;^40,41 however, both of these nicotine delivery systems sustain nicotine addiction.

Despite many ongoing studies to determine if e-cigarettes are useful as a smoking cessation aid, the results vary widely and are inconclusive at this time.⁴²

E-cigarettes do not increase long-term tobacco abstinence

Contrary to popular belief, research shows that e-cigarette use among smokers is not associated with long-term tobacco abstinence.¹ E-cigarette users, however, may make more attempts to quit smoking compared with smokers not using them.⁴³ In addition, even though there is some evidence that e-cigarettes help smokers reduce the number of cigarettes smoked per day, simply reducing the daily number of cigarettes does not equate with safety.⁴⁴ Smoking just one to 4 cigarettes per day poses 3 times the risk of myocardial infarction and lung cancer compared with not smoking.⁴⁴ And since many individuals continue to use traditional and electronic cigarettes, they end up in double jeopardy of toxicity through exposure to the dangers of both.

A gateway to other substances of abuse?

Pregnant and breastfeeding women should not replace tobacco cigarettes with e-cigarettes.

There is also fear that nicotine exposure via e-cigarettes, especially in young people, serves as a “gateway” to tobacco consumption and other substance abuses, and increases the risk for nicotine addiction.³⁴ Such nicotine-induced effects are a result of changes in brain chemistry, and have been documented in humans and animals.³⁴

These concerns about negative health consequences, combined with the fact that e-cigarettes are undocumented as a smoking cessation aid, add urgency to the need for legislative and regulatory actions that hopefully can curb all nicotine exposures, particularly for our nation’s youth. In the meantime, it is important for physicians to advise patients—and the public—about the risks of e-cigarettes and the importance of quitting all forms of nicotine inhalation because nicotine—regardless of how it is delivered—is still an addictive drug.

CORRESPONDENCE
Steven Lippmann, MD, University of Louisville School of Medicine, 401 E. Chestnut Street, Suite 610, Louisville, KY 40202; [email protected].

It’s been about 2 years since I had my first e-cigarette discussion with a patient. He was a smoker in his 30s and, since we routinely screen for tobacco use in our practice, I asked him if he was interested in quitting. He said he was cutting down by using e-cigarettes, but had not yet stopped smoking.

According to the 2 articles on e-cigarettes in this issue—one original research study about the prevalence of e-cigarette use in rural Illinois and one review of the safety of e-cigarettes—my experience with this patient is typical of e-cigarette users. Many are “dual users” who turn to e-cigarettes to try to cut down on their tobacco use.

As these 2 articles discuss, we still have a great deal to learn about the potential harms and benefits of e-cigarettes. What chemicals are people taking into their bodies and how dangerous are they? And even if they pose health risks, do e-cigarettes have value as smoking cessation aids if they are less harmful than tobacco?

One could simply take a “just say No” approach, as does my wife who says, “Any chemical you inhale into your lungs can’t be good for you!” Or, one can assume the more moderate lesser-of-two-evils stance of the British health system, which posits that there may be some benefit to e-cigarettes if they help people cut down or stop using tobacco products.

Are e-cigarettes a "gateway" to the use of tobacco and other substances of abuse? Or do they represent an effective way to quit smoking?

In writing this editorial, I conducted a quick literature search that yielded only 5 legitimate randomized trials of e-cigarettes to reduce or eliminate tobacco use, and the results were underwhelming. At best, e-cigarettes appear to be as effective as other forms of nicotine replacement, such as patches, which do not have chemical additives.

Fortunately, researchers are taking e-cigarettes seriously, and research is ongoing. Using the search term “e-cigarette” yielded 2058 references, indicating a respectable amount of e-cigarette research conducted over the past 6 years. Most of the research so far has been about the chemical constituents of the vapor people inhale or about use patterns. There is still a lack of definitive research on whether e-cigarettes are an effective smoking cessation method or a “gateway” to the use of tobacco and other substances of abuse.

Or perhaps they are both.

Hopefully, in 5 years we will know a great deal more, but until we do, I am happy to see that the US Food and Drug Administration has decided to regulate e-cigarettes like tobacco.

It’s been about 2 years since I had my first e-cigarette discussion with a patient. He was a smoker in his 30s and, since we routinely screen for tobacco use in our practice, I asked him if he was interested in quitting. He said he was cutting down by using e-cigarettes, but had not yet stopped smoking.

According to the 2 articles on e-cigarettes in this issue—one original research study about the prevalence of e-cigarette use in rural Illinois and one review of the safety of e-cigarettes—my experience with this patient is typical of e-cigarette users. Many are “dual users” who turn to e-cigarettes to try to cut down on their tobacco use.

As these 2 articles discuss, we still have a great deal to learn about the potential harms and benefits of e-cigarettes. What chemicals are people taking into their bodies and how dangerous are they? And even if they pose health risks, do e-cigarettes have value as smoking cessation aids if they are less harmful than tobacco?

One could simply take a “just say No” approach, as does my wife who says, “Any chemical you inhale into your lungs can’t be good for you!” Or, one can assume the more moderate lesser-of-two-evils stance of the British health system, which posits that there may be some benefit to e-cigarettes if they help people cut down or stop using tobacco products.

Are e-cigarettes a "gateway" to the use of tobacco and other substances of abuse? Or do they represent an effective way to quit smoking?

In writing this editorial, I conducted a quick literature search that yielded only 5 legitimate randomized trials of e-cigarettes to reduce or eliminate tobacco use, and the results were underwhelming. At best, e-cigarettes appear to be as effective as other forms of nicotine replacement, such as patches, which do not have chemical additives.

Fortunately, researchers are taking e-cigarettes seriously, and research is ongoing. Using the search term “e-cigarette” yielded 2058 references, indicating a respectable amount of e-cigarette research conducted over the past 6 years. Most of the research so far has been about the chemical constituents of the vapor people inhale or about use patterns. There is still a lack of definitive research on whether e-cigarettes are an effective smoking cessation method or a “gateway” to the use of tobacco and other substances of abuse.

Or perhaps they are both.

Hopefully, in 5 years we will know a great deal more, but until we do, I am happy to see that the US Food and Drug Administration has decided to regulate e-cigarettes like tobacco.

It’s been about 2 years since I had my first e-cigarette discussion with a patient. He was a smoker in his 30s and, since we routinely screen for tobacco use in our practice, I asked him if he was interested in quitting. He said he was cutting down by using e-cigarettes, but had not yet stopped smoking.

According to the 2 articles on e-cigarettes in this issue—one original research study about the prevalence of e-cigarette use in rural Illinois and one review of the safety of e-cigarettes—my experience with this patient is typical of e-cigarette users. Many are “dual users” who turn to e-cigarettes to try to cut down on their tobacco use.

As these 2 articles discuss, we still have a great deal to learn about the potential harms and benefits of e-cigarettes. What chemicals are people taking into their bodies and how dangerous are they? And even if they pose health risks, do e-cigarettes have value as smoking cessation aids if they are less harmful than tobacco?

One could simply take a “just say No” approach, as does my wife who says, “Any chemical you inhale into your lungs can’t be good for you!” Or, one can assume the more moderate lesser-of-two-evils stance of the British health system, which posits that there may be some benefit to e-cigarettes if they help people cut down or stop using tobacco products.

Are e-cigarettes a "gateway" to the use of tobacco and other substances of abuse? Or do they represent an effective way to quit smoking?

In writing this editorial, I conducted a quick literature search that yielded only 5 legitimate randomized trials of e-cigarettes to reduce or eliminate tobacco use, and the results were underwhelming. At best, e-cigarettes appear to be as effective as other forms of nicotine replacement, such as patches, which do not have chemical additives.

Fortunately, researchers are taking e-cigarettes seriously, and research is ongoing. Using the search term “e-cigarette” yielded 2058 references, indicating a respectable amount of e-cigarette research conducted over the past 6 years. Most of the research so far has been about the chemical constituents of the vapor people inhale or about use patterns. There is still a lack of definitive research on whether e-cigarettes are an effective smoking cessation method or a “gateway” to the use of tobacco and other substances of abuse.

Or perhaps they are both.

Hopefully, in 5 years we will know a great deal more, but until we do, I am happy to see that the US Food and Drug Administration has decided to regulate e-cigarettes like tobacco.

ABSTRACT

Background Electronic cigarettes (e-cigarettes) are often marketed as safe and effective aids for quitting cigarette smoking, but concerns remain that use of e-cigarettes might actually reduce the number of quit attempts. To address these issues, we characterized the utilization and demographic correlates of dual use of e-cigarettes and traditional cigarettes (referred to here as simply “cigarettes”) among smokers in a rural population of Illinois.

Methods The majority of survey participants were recruited from the 2014 Illinois State Fair and from another event—the Springfield Mile (a motorcycle racing event)—in Springfield, Ill. Survey questions explored participant demographics and cigarette and e-cigarette use history.

Results Of 201 total cigarette smokers, 79 smoked only tobacco cigarettes (smokers), while 122 also used e-cigarettes (dual users). Dual users did not differ significantly from smokers in gender, age, income, or education. Compared to smokers, dual users were more likely to smoke within 30 minutes of awakening (odds ratio [OR]=3.3; 95% confidence interval [CI], 1.8-6.3), but did not smoke more cigarettes per day or perceive a greater likelihood of quit success. Non-white dual users smoked fewer cigarettes per day than smokers. In addition, 79.5% of all dual users reported that they were using e-cigarettes to quit smoking or reduce the number of cigarettes smoked, and white respondents were 6 times more likely than non-whites to use e-cigarettes for ‘trying to quit smoking’ (OR=6.0; 95% CI, 1.1-32.9). Males and respondents with lower income were less likely to say they were using e-cigarettes to reduce the number of cigarettes smoked than females or participants with higher income (OR=0.2; 95% CI, 0.1-0.8 and OR=0.1; 95% CI, 0.0-0.5, respectively).

Conclusions E-cigarettes may significantly alter the landscape of nicotine physical dependence, and local influences likely are associated with use patterns. Future research should continue to examine whether dual use of traditional and electronic cigarettes impacts smoking cessation, and clinicians should be aware that local norms may create differences from national level data.

Approximately 21% of US adults use tobacco products at least occasionally.¹ Although smoking prevalence has declined in recent years (from 21% in 2005 to 18% in 2013), it remains high among certain groups (eg, males and those with a high school education or less).² As we know, the health burden of smoking—as a cause of death from cancer, pulmonary disease, and heart disease—is substantial,^3,4 and rural areas experience a significantly higher prevalence of smoking compared to urban areas.^2,5,6

However, it is unknown if the context and habits surrounding tobacco use in rural and/or Midwestern areas are similar to those of urban or nationally-representative populations. For example, while many urban residents may encounter a multitude of media messages encouraging smoking cessation resulting in less community acceptance of smoking, rural residents may be exposed to substantially fewer messages (eg, no city bus signs, billboards, subway posters, etc.) and the community may be more accommodating and tolerant of smoking.

Do e-cigarettes increase cigarette smoking?

Two-thirds of physicians report being asked about e-cigarettes by their patients, and one-third recommend using them as a smoking cessation aid.

Public health professionals are concerned about the increased use of e-cigarettes, particularly among young people, and whether this use increases the likelihood that individuals will start smoking tobacco cigarettes.⁷(Throughout this paper, we will use “cigarettes” and “smoking” to refer to the use of traditional tobacco cigarettes.) A recent study found that adolescents who used electronic nicotine delivery systems were twice as likely as non-users to have tried cigarettes in the past year.⁸

An onslaught of advertising. There are also concerns that e-cigarettes may serve to ‘renormalize’ nicotine addiction, in part through large-scale advertising, which was seen by nearly 70% of the participants in the 2014 National Youth Tobacco Survey.⁹ Largely as a result of that advertising, e-cigarette sales exceed $1.7 billion in the United States alone.¹⁰ With 15% of all US adults having ever tried electronic nicotine delivery systems and more than half (52%) of smokers having done so, questions regarding their health impact cannot be taken lightly.¹¹

Do e-cigarettes help people quit smoking? E-cigarettes are often marketed as a safe and effective means for quitting cigarette smoking.^12-14 (See "E-cigarettes: How "safe" are they?") Nearly two-thirds of physicians report being asked about e-cigarettes by their patients and approximately one-third of physicians recommend using them as a smoking cessation aid.¹⁵

Claims regarding the usefulness of e-cigarettes in smoking cessation, however, have not been substantiated by high-quality randomized controlled trials (RCTs). In fact, no RCTs have shown them to be safer or more effective than cessation treatments currently approved by the US Food and Drug Administration.^16,17

Two studies reflect the conflicting data that are currently available. One small study found intensive e-cigarette users were 6 times more likely than non-users/triers to report successful smoking cessation.¹⁸ However, researchers surveying callers of a cigarette quit line found that smokers who used e-cigarettes (dual users) were less likely to quit smoking than non-users.¹⁹

The lack of good-quality data substantiates the concern that dual use might discourage quitting by normalizing cigarette use and reducing perceptions of harm.^20,21 Dual use may also hamper smoking cessation efforts by increasing nicotine physical dependence and associated withdrawal symptoms when trying to quit.²² And finally, dual use may expose users to more carcinogens and toxins than those who use only one product, and the average number of cigarettes smoked per day may be significantly higher among dual users.²³

Unique demographic factors at work? Finally, the social and community context within which smoking occurs, and the prevalence of smoking-associated demographic risk factors, may vary significantly between rural and urban areas and between seemingly similar rural areas.^24-27 Few studies have examined differences in e-cigarette use between rural and urban areas. Those that have are contradictory, reporting that rural residents use e-cigarettes both more and less than their urban peers,^28,29 but many of these studies were conducted outside the United States, where the context and norms associated with smoking and e-cigarette use likely vary.

For these reasons, we sought to examine e-cigarette use among residents of Illinois, the nation’s fifth largest state and one with a rural population exceeding 1.5 million.³⁰ We compared dual users of e-cigarettes and cigarettes to smokers of cigarettes only in terms of demographic characteristics, nicotine physical dependence, and smoking cessation beliefs, and explored dual smokers' reasons for using both types of cigarettes.

MATERIALS AND METHODS

Dual users were no more likely than smokers to have attempted to quit smoking within the past year.

A survey was fielded during August and September 2014 in Springfield, Ill. To obtain responses, a booth was set up at both the Illinois State Fair and the Springfield Mile (a motorcycle racing event), and participants were recruited via direct solicitation by project staff. This was supplemented by an email invitation to all employees of the Southern Illinois University School of Medicine. The 2 venues and the email strategy were chosen because they draw from a large area of central and southern Illinois and were convenient to the location of the study team. Individuals were eligible to participate if they were ≥18 years of age and used any tobacco product or e-cigarettes. Survey elements were derived from 2 national surveys of health and behavior—the Minnesota Adult Tobacco Survey 2010³¹ and the Brief Smoking Consequences Questionnaire-Adult.³²

Survey questions assessed cigarette use, nicotine physical dependence, social norms, perceived risks and benefits, and smoking cessation beliefs and behaviors. Questions were slightly reworded to address not only the use of traditional cigarettes, but the use of e-cigarettes, as well. Ultimately, each participant answered a similarly-worded set of questions for both regular and e-cigarettes. Dual use of cigarettes and e-cigarettes was also assessed. Participants self-reported all data and survey responses on an electronic tablet and received a $10 (cash or gift card) incentive. This project was reviewed and approved by the Springfield Committee for Research Involving Human Subjects.

Stratification of results. Race was dichotomized into white and non-white. Education was stratified into 3 categories: up to and including high school graduation, some college but not a Bachelor’s degree, and Bachelor’s degree and above. Income was divided as being ≤$20,000 or >$20,000, and age was split into 2 groups by the median value. Analyses included descriptions of participant demographics, dual use status, measures of nicotine physical dependence, quit attempts, and e-cigarette use motivations. Bivariate relationships between dual use status and demographic characteristics, nicotine physical dependence, and smoking cessation beliefs were analyzed by chi-square (categorical variables) and ANOVA (continuous/Likert variables).

Multivariable logistic regression modeling of the demographic variables and dual use status (cigarette smoker only vs dual user) was performed to predict 3 factors: number of cigarettes smoked per day (≤10 vs 11+); time to first cigarette (≤30 vs 31+ minutes from waking); and perceived likelihood of quit attempt success (very/somewhat likely vs very/somewhat unlikely). Multivariable models examining the reasons for dual use included the demographic, nicotine physical dependence, and cessation belief items described previously.

RESULTS

Dual users were approximately 3 times more likely than smokers to smoke their first cigarette within 30 minutes of waking.

Of 309 total survey participants (Fair=288; Race=12; Email=9), there were 235 current cigarette smokers consisting of 79 who smoked only cigarettes (smokers); 122 who used both cigarettes and e-cigarettes (dual users); and 34 former e-cigarette users. Only smokers and dual users were included in this analysis (N=201, although for the purposes of TABLE 1, N=200 or 199 because at least one participant did not provide answers to all of the questions). Approximately 51% of the smokers were male, 78% were white, 12% were 4-year college graduates, and 57% reported incomes >$20,000. The mean age was 37.7 years (SD=14.4); 50% of respondents were <35 years of age. Dual users did not vary significantly from smokers in terms of gender, age, education, or income (all P>.05). However, a greater proportion of whites vs non-whites were dual users (54.9% vs 42.3%; P=.035).

Click here to see an enlarged version of the table.

No big quit differences. Bivariate analyses revealed that dual users were no more likely than smokers to have attempted to quit smoking within the past year (X²=2.3; P=.14), consider quitting in the next one or 6 months (X²=1.1; P=.34), or differ in perceived likelihood of cessation success (X²=0.0; P=1.00). The proportion of dual users who smoked 11+ cigarettes per day did not differ from that of cigarette smokers for the group as a whole or when the group was stratified by gender, income, education, or age. However, among non-whites, dual users smoked fewer cigarettes than cigarette smokers (TABLE 1).

Predicting physical dependence. Significant differences also were observed regarding the timing of the first cigarette of the day, with dual users approximately 3 times more likely than smokers to smoke within 30 minutes of awakening (80% vs 54.4%; OR=3.3; 95% CI, 1.8-6.3), and this difference was upheld among males, females, whites, those with an income >$20,000, those with a high school education or less and those with some college education, and age >34 years. There was no association, however, between dual use and perceived likelihood of quit success.

We then performed multivariable logistic modeling on dual users to determine which variables might predict 3 measures of physical dependence: number of cigarettes smoked per day (≤10 vs 11+), time between waking and smoking the first cigarette of the day (≤30 vs 31+ minutes), and perceived likelihood of cessation success (TABLE 2). Male gender (OR=3.4; 95% CI, 1.8-6.5) and white race (OR=4.4; 95% CI, 1.9-10.1) were significant for predicting smoking 11+ cigarettes a day, while dual use status was insignificant (P=.104). Regarding time to first cigarette, only dual use was significant (OR=3.1; 95% CI, 1.6-5.9), with dual users approximately 3 times more likely than smokers to have their first cigarette within 30 minutes of waking. No variables were significant in predicting perceived likelihood of quit success.

Reasons for dual use. We examined reasons for dual use with the question: Do you use e-cigarettes to reduce your regular tobacco use? Here, 79.5% of smokers reported using e-cigarettes to quit smoking or reduce the number of cigarettes smoked.

A multivariable polynomial logistic regression that included only dual users was performed to examine which variables might predict use for tobacco cessation (“trying to quit smoking”) vs reduction in smoking intensity (“trying to reduce the number of regular cigarettes I smoke per day”) vs no change (“use the same amount of tobacco as always”) (TABLE 2). Whites were approximately 6 times more likely than non-whites to indicate they engage in dual use to try to quit smoking (OR=6.0; 95% CI, 1.1-32.9). Males and people with lower incomes were much less likely to indicate they engaged in dual use to try to reduce the number of regular cigarettes smoked than females or those with higher incomes (OR=0.2; 95% CI, 0.1-0.8 and OR=0.1, 95% CI, 0.0-0.5, respectively). No other demographic variables or measures of nicotine physical dependence were significantly different between dual users and smokers.

Click here to see an enlarged version of the table.

DISCUSSION

Dual use was associated with a shorter time to first cigarette, but not a greater number of cigarettes smoked or perceived ability to successfully quit smoking.

E-cigarettes are used by approximately half of smokers (52%), which is much higher than that reported by Delnevo, et al, in their analysis of the National Health Interview Study.³³ There, prevalence of dual use of both cigarettes and e-cigarettes ranged from 3.4% to 12.7%. This substantial difference raises important questions regarding study population characterization. Were participants in our study representative of central Illinois, state fair attendees, or the agricultural profession? Further work to identify this group with an increased propensity for dual use will assist clinicians in developing appropriate intervention strategies.

Dual use in our study did not vary by many customary demographic variables. Nor was it associated with different rates of past or future quit attempts or perceived ability to successfully quit if quitting was attempted. These factors—high rates of dual use and insignificant effect on quit attempts—may have implications for local physicians counseling patients who smoke.

In our study, the majority of smokers already use e-cigarettes, and this does not seem to increase their ability/likelihood to quit smoking. Further, dual use did not seem to be associated with overall cigarette consumption; males and white participants smoked more cigarettes than females and non-whites. But dual use was associated with a measure of increased nicotine physical dependence (earlier first cigarette of the day). As a result, physicians may want to think twice before recommending e-cigarette use as a means of smoking cessation.

In addition to the high prevalence of e-cigarette use among smokers, a number of other interesting findings surfaced that run counter to some of the current literature. First, dual users are no more likely than smokers to have tried to quit in the past or to try to quit in the future.^21,22,34 It could be that for the relatively small geographical area from which our participants were recruited (central Illinois; ~77% of participants from Sangamon County alone), the local context and culture of smoking differs from that associated with participants in other studies, who were mostly recruited from national and regional online surveys. However, there is no a priori reason to suspect Sangamon County is especially different, as it is quite similar to Illinois as a whole by many measures (eg, percentage rural: 14.1% vs 11.5%; percentage black (only): 12.4% vs 14.7%; education to at least a Bachelor’s degree: 33.0% vs 31.9%; and median household income: $55,565 vs $57,166).³⁰

While we found that dual users did have one measure of increased nicotine physical dependence, the total number of cigarettes consumed per day was not significantly different from that of smokers.^23-25 This is contrary to another study of nicotine physical dependence, but, unlike that study, we did not assess length of time of concurrent use.³⁵ There is much uncertainty surrounding the issue of nicotine physical dependence and e-cigarette use, largely because the level of nicotine delivered by various e-products varies significantly.³⁶

Cross-sectional nature, small sample size limit utility of data

There are significant limitations to this study, including the cross-sectional nature of the data, the small sample size, the use of self-report, and the limited scope of recruitment. The relatively small sample size limits our ability to observe small differences and effect sizes. However, small differences often lack practical significance. Finally, participation was limited to those attending a state fair or a local sporting event and those employed by a local medical school. Thus, the results may not be generalizable to populations outside central Illinois. On the other hand, the very low income sample recruited from the Midwestern US, which is underrepresented in prior e-cigarette research, might represent some of the strengths of this work.

Future investigations. Future studies should more closely examine e-cigarette use prevalence on smaller geographic scales and especially in rural areas where there is a paucity of research. As the majority of our respondents came from a single county in central Illinois, one has to ask the questions, “Is this a ‘hot spot’ for e-cigarette use?" And "Do other rural areas experience similar use?” It may be important to know if national surveys are sensitive enough to observe significant local variations. Research also should examine how e-cigarette use and the influence of local culture vary across wider areas.

Several specific areas of study would help to inform policy and intervention development. For example, is tobacco cigarette quit success impacted by concurrent e-cigarette use? While our study showed no difference in past or possible future quit attempts among dual users as compared with smokers, we did not assess actual quit success, and multiple participants in our study anecdotally described using e-cigarettes to successfully quit smoking.

In the end, the rapid increase in the use of e-cigarettes has the potential to significantly alter the landscape of nicotine physical dependence, and local culture and other influences are likely associated with use patterns.

CORRESPONDENCE
Wiley D. Jenkins, PhD, MPH, Science Director, Population Health Science Program, Southern Illinois University School of Medicine, 201 E. Madison St., Springfield, IL 62794-9664; [email protected].

ABSTRACT

Background Electronic cigarettes (e-cigarettes) are often marketed as safe and effective aids for quitting cigarette smoking, but concerns remain that use of e-cigarettes might actually reduce the number of quit attempts. To address these issues, we characterized the utilization and demographic correlates of dual use of e-cigarettes and traditional cigarettes (referred to here as simply “cigarettes”) among smokers in a rural population of Illinois.

Methods The majority of survey participants were recruited from the 2014 Illinois State Fair and from another event—the Springfield Mile (a motorcycle racing event)—in Springfield, Ill. Survey questions explored participant demographics and cigarette and e-cigarette use history.

Results Of 201 total cigarette smokers, 79 smoked only tobacco cigarettes (smokers), while 122 also used e-cigarettes (dual users). Dual users did not differ significantly from smokers in gender, age, income, or education. Compared to smokers, dual users were more likely to smoke within 30 minutes of awakening (odds ratio [OR]=3.3; 95% confidence interval [CI], 1.8-6.3), but did not smoke more cigarettes per day or perceive a greater likelihood of quit success. Non-white dual users smoked fewer cigarettes per day than smokers. In addition, 79.5% of all dual users reported that they were using e-cigarettes to quit smoking or reduce the number of cigarettes smoked, and white respondents were 6 times more likely than non-whites to use e-cigarettes for ‘trying to quit smoking’ (OR=6.0; 95% CI, 1.1-32.9). Males and respondents with lower income were less likely to say they were using e-cigarettes to reduce the number of cigarettes smoked than females or participants with higher income (OR=0.2; 95% CI, 0.1-0.8 and OR=0.1; 95% CI, 0.0-0.5, respectively).

Conclusions E-cigarettes may significantly alter the landscape of nicotine physical dependence, and local influences likely are associated with use patterns. Future research should continue to examine whether dual use of traditional and electronic cigarettes impacts smoking cessation, and clinicians should be aware that local norms may create differences from national level data.

Approximately 21% of US adults use tobacco products at least occasionally.¹ Although smoking prevalence has declined in recent years (from 21% in 2005 to 18% in 2013), it remains high among certain groups (eg, males and those with a high school education or less).² As we know, the health burden of smoking—as a cause of death from cancer, pulmonary disease, and heart disease—is substantial,^3,4 and rural areas experience a significantly higher prevalence of smoking compared to urban areas.^2,5,6

However, it is unknown if the context and habits surrounding tobacco use in rural and/or Midwestern areas are similar to those of urban or nationally-representative populations. For example, while many urban residents may encounter a multitude of media messages encouraging smoking cessation resulting in less community acceptance of smoking, rural residents may be exposed to substantially fewer messages (eg, no city bus signs, billboards, subway posters, etc.) and the community may be more accommodating and tolerant of smoking.

Do e-cigarettes increase cigarette smoking?

Two-thirds of physicians report being asked about e-cigarettes by their patients, and one-third recommend using them as a smoking cessation aid.

Public health professionals are concerned about the increased use of e-cigarettes, particularly among young people, and whether this use increases the likelihood that individuals will start smoking tobacco cigarettes.⁷(Throughout this paper, we will use “cigarettes” and “smoking” to refer to the use of traditional tobacco cigarettes.) A recent study found that adolescents who used electronic nicotine delivery systems were twice as likely as non-users to have tried cigarettes in the past year.⁸

An onslaught of advertising. There are also concerns that e-cigarettes may serve to ‘renormalize’ nicotine addiction, in part through large-scale advertising, which was seen by nearly 70% of the participants in the 2014 National Youth Tobacco Survey.⁹ Largely as a result of that advertising, e-cigarette sales exceed $1.7 billion in the United States alone.¹⁰ With 15% of all US adults having ever tried electronic nicotine delivery systems and more than half (52%) of smokers having done so, questions regarding their health impact cannot be taken lightly.¹¹

Do e-cigarettes help people quit smoking? E-cigarettes are often marketed as a safe and effective means for quitting cigarette smoking.^12-14 (See "E-cigarettes: How "safe" are they?") Nearly two-thirds of physicians report being asked about e-cigarettes by their patients and approximately one-third of physicians recommend using them as a smoking cessation aid.¹⁵

Claims regarding the usefulness of e-cigarettes in smoking cessation, however, have not been substantiated by high-quality randomized controlled trials (RCTs). In fact, no RCTs have shown them to be safer or more effective than cessation treatments currently approved by the US Food and Drug Administration.^16,17

Two studies reflect the conflicting data that are currently available. One small study found intensive e-cigarette users were 6 times more likely than non-users/triers to report successful smoking cessation.¹⁸ However, researchers surveying callers of a cigarette quit line found that smokers who used e-cigarettes (dual users) were less likely to quit smoking than non-users.¹⁹

The lack of good-quality data substantiates the concern that dual use might discourage quitting by normalizing cigarette use and reducing perceptions of harm.^20,21 Dual use may also hamper smoking cessation efforts by increasing nicotine physical dependence and associated withdrawal symptoms when trying to quit.²² And finally, dual use may expose users to more carcinogens and toxins than those who use only one product, and the average number of cigarettes smoked per day may be significantly higher among dual users.²³

Unique demographic factors at work? Finally, the social and community context within which smoking occurs, and the prevalence of smoking-associated demographic risk factors, may vary significantly between rural and urban areas and between seemingly similar rural areas.^24-27 Few studies have examined differences in e-cigarette use between rural and urban areas. Those that have are contradictory, reporting that rural residents use e-cigarettes both more and less than their urban peers,^28,29 but many of these studies were conducted outside the United States, where the context and norms associated with smoking and e-cigarette use likely vary.

For these reasons, we sought to examine e-cigarette use among residents of Illinois, the nation’s fifth largest state and one with a rural population exceeding 1.5 million.³⁰ We compared dual users of e-cigarettes and cigarettes to smokers of cigarettes only in terms of demographic characteristics, nicotine physical dependence, and smoking cessation beliefs, and explored dual smokers' reasons for using both types of cigarettes.

MATERIALS AND METHODS

Dual users were no more likely than smokers to have attempted to quit smoking within the past year.

A survey was fielded during August and September 2014 in Springfield, Ill. To obtain responses, a booth was set up at both the Illinois State Fair and the Springfield Mile (a motorcycle racing event), and participants were recruited via direct solicitation by project staff. This was supplemented by an email invitation to all employees of the Southern Illinois University School of Medicine. The 2 venues and the email strategy were chosen because they draw from a large area of central and southern Illinois and were convenient to the location of the study team. Individuals were eligible to participate if they were ≥18 years of age and used any tobacco product or e-cigarettes. Survey elements were derived from 2 national surveys of health and behavior—the Minnesota Adult Tobacco Survey 2010³¹ and the Brief Smoking Consequences Questionnaire-Adult.³²

Survey questions assessed cigarette use, nicotine physical dependence, social norms, perceived risks and benefits, and smoking cessation beliefs and behaviors. Questions were slightly reworded to address not only the use of traditional cigarettes, but the use of e-cigarettes, as well. Ultimately, each participant answered a similarly-worded set of questions for both regular and e-cigarettes. Dual use of cigarettes and e-cigarettes was also assessed. Participants self-reported all data and survey responses on an electronic tablet and received a $10 (cash or gift card) incentive. This project was reviewed and approved by the Springfield Committee for Research Involving Human Subjects.

Stratification of results. Race was dichotomized into white and non-white. Education was stratified into 3 categories: up to and including high school graduation, some college but not a Bachelor’s degree, and Bachelor’s degree and above. Income was divided as being ≤$20,000 or >$20,000, and age was split into 2 groups by the median value. Analyses included descriptions of participant demographics, dual use status, measures of nicotine physical dependence, quit attempts, and e-cigarette use motivations. Bivariate relationships between dual use status and demographic characteristics, nicotine physical dependence, and smoking cessation beliefs were analyzed by chi-square (categorical variables) and ANOVA (continuous/Likert variables).

Multivariable logistic regression modeling of the demographic variables and dual use status (cigarette smoker only vs dual user) was performed to predict 3 factors: number of cigarettes smoked per day (≤10 vs 11+); time to first cigarette (≤30 vs 31+ minutes from waking); and perceived likelihood of quit attempt success (very/somewhat likely vs very/somewhat unlikely). Multivariable models examining the reasons for dual use included the demographic, nicotine physical dependence, and cessation belief items described previously.

RESULTS

Dual users were approximately 3 times more likely than smokers to smoke their first cigarette within 30 minutes of waking.

Of 309 total survey participants (Fair=288; Race=12; Email=9), there were 235 current cigarette smokers consisting of 79 who smoked only cigarettes (smokers); 122 who used both cigarettes and e-cigarettes (dual users); and 34 former e-cigarette users. Only smokers and dual users were included in this analysis (N=201, although for the purposes of TABLE 1, N=200 or 199 because at least one participant did not provide answers to all of the questions). Approximately 51% of the smokers were male, 78% were white, 12% were 4-year college graduates, and 57% reported incomes >$20,000. The mean age was 37.7 years (SD=14.4); 50% of respondents were <35 years of age. Dual users did not vary significantly from smokers in terms of gender, age, education, or income (all P>.05). However, a greater proportion of whites vs non-whites were dual users (54.9% vs 42.3%; P=.035).

Click here to see an enlarged version of the table.

No big quit differences. Bivariate analyses revealed that dual users were no more likely than smokers to have attempted to quit smoking within the past year (X²=2.3; P=.14), consider quitting in the next one or 6 months (X²=1.1; P=.34), or differ in perceived likelihood of cessation success (X²=0.0; P=1.00). The proportion of dual users who smoked 11+ cigarettes per day did not differ from that of cigarette smokers for the group as a whole or when the group was stratified by gender, income, education, or age. However, among non-whites, dual users smoked fewer cigarettes than cigarette smokers (TABLE 1).

Predicting physical dependence. Significant differences also were observed regarding the timing of the first cigarette of the day, with dual users approximately 3 times more likely than smokers to smoke within 30 minutes of awakening (80% vs 54.4%; OR=3.3; 95% CI, 1.8-6.3), and this difference was upheld among males, females, whites, those with an income >$20,000, those with a high school education or less and those with some college education, and age >34 years. There was no association, however, between dual use and perceived likelihood of quit success.

We then performed multivariable logistic modeling on dual users to determine which variables might predict 3 measures of physical dependence: number of cigarettes smoked per day (≤10 vs 11+), time between waking and smoking the first cigarette of the day (≤30 vs 31+ minutes), and perceived likelihood of cessation success (TABLE 2). Male gender (OR=3.4; 95% CI, 1.8-6.5) and white race (OR=4.4; 95% CI, 1.9-10.1) were significant for predicting smoking 11+ cigarettes a day, while dual use status was insignificant (P=.104). Regarding time to first cigarette, only dual use was significant (OR=3.1; 95% CI, 1.6-5.9), with dual users approximately 3 times more likely than smokers to have their first cigarette within 30 minutes of waking. No variables were significant in predicting perceived likelihood of quit success.

Reasons for dual use. We examined reasons for dual use with the question: Do you use e-cigarettes to reduce your regular tobacco use? Here, 79.5% of smokers reported using e-cigarettes to quit smoking or reduce the number of cigarettes smoked.

A multivariable polynomial logistic regression that included only dual users was performed to examine which variables might predict use for tobacco cessation (“trying to quit smoking”) vs reduction in smoking intensity (“trying to reduce the number of regular cigarettes I smoke per day”) vs no change (“use the same amount of tobacco as always”) (TABLE 2). Whites were approximately 6 times more likely than non-whites to indicate they engage in dual use to try to quit smoking (OR=6.0; 95% CI, 1.1-32.9). Males and people with lower incomes were much less likely to indicate they engaged in dual use to try to reduce the number of regular cigarettes smoked than females or those with higher incomes (OR=0.2; 95% CI, 0.1-0.8 and OR=0.1, 95% CI, 0.0-0.5, respectively). No other demographic variables or measures of nicotine physical dependence were significantly different between dual users and smokers.

Click here to see an enlarged version of the table.

DISCUSSION

Dual use was associated with a shorter time to first cigarette, but not a greater number of cigarettes smoked or perceived ability to successfully quit smoking.

E-cigarettes are used by approximately half of smokers (52%), which is much higher than that reported by Delnevo, et al, in their analysis of the National Health Interview Study.³³ There, prevalence of dual use of both cigarettes and e-cigarettes ranged from 3.4% to 12.7%. This substantial difference raises important questions regarding study population characterization. Were participants in our study representative of central Illinois, state fair attendees, or the agricultural profession? Further work to identify this group with an increased propensity for dual use will assist clinicians in developing appropriate intervention strategies.

Dual use in our study did not vary by many customary demographic variables. Nor was it associated with different rates of past or future quit attempts or perceived ability to successfully quit if quitting was attempted. These factors—high rates of dual use and insignificant effect on quit attempts—may have implications for local physicians counseling patients who smoke.

In our study, the majority of smokers already use e-cigarettes, and this does not seem to increase their ability/likelihood to quit smoking. Further, dual use did not seem to be associated with overall cigarette consumption; males and white participants smoked more cigarettes than females and non-whites. But dual use was associated with a measure of increased nicotine physical dependence (earlier first cigarette of the day). As a result, physicians may want to think twice before recommending e-cigarette use as a means of smoking cessation.

In addition to the high prevalence of e-cigarette use among smokers, a number of other interesting findings surfaced that run counter to some of the current literature. First, dual users are no more likely than smokers to have tried to quit in the past or to try to quit in the future.^21,22,34 It could be that for the relatively small geographical area from which our participants were recruited (central Illinois; ~77% of participants from Sangamon County alone), the local context and culture of smoking differs from that associated with participants in other studies, who were mostly recruited from national and regional online surveys. However, there is no a priori reason to suspect Sangamon County is especially different, as it is quite similar to Illinois as a whole by many measures (eg, percentage rural: 14.1% vs 11.5%; percentage black (only): 12.4% vs 14.7%; education to at least a Bachelor’s degree: 33.0% vs 31.9%; and median household income: $55,565 vs $57,166).³⁰

While we found that dual users did have one measure of increased nicotine physical dependence, the total number of cigarettes consumed per day was not significantly different from that of smokers.^23-25 This is contrary to another study of nicotine physical dependence, but, unlike that study, we did not assess length of time of concurrent use.³⁵ There is much uncertainty surrounding the issue of nicotine physical dependence and e-cigarette use, largely because the level of nicotine delivered by various e-products varies significantly.³⁶

Cross-sectional nature, small sample size limit utility of data

There are significant limitations to this study, including the cross-sectional nature of the data, the small sample size, the use of self-report, and the limited scope of recruitment. The relatively small sample size limits our ability to observe small differences and effect sizes. However, small differences often lack practical significance. Finally, participation was limited to those attending a state fair or a local sporting event and those employed by a local medical school. Thus, the results may not be generalizable to populations outside central Illinois. On the other hand, the very low income sample recruited from the Midwestern US, which is underrepresented in prior e-cigarette research, might represent some of the strengths of this work.

Future investigations. Future studies should more closely examine e-cigarette use prevalence on smaller geographic scales and especially in rural areas where there is a paucity of research. As the majority of our respondents came from a single county in central Illinois, one has to ask the questions, “Is this a ‘hot spot’ for e-cigarette use?" And "Do other rural areas experience similar use?” It may be important to know if national surveys are sensitive enough to observe significant local variations. Research also should examine how e-cigarette use and the influence of local culture vary across wider areas.

Several specific areas of study would help to inform policy and intervention development. For example, is tobacco cigarette quit success impacted by concurrent e-cigarette use? While our study showed no difference in past or possible future quit attempts among dual users as compared with smokers, we did not assess actual quit success, and multiple participants in our study anecdotally described using e-cigarettes to successfully quit smoking.

In the end, the rapid increase in the use of e-cigarettes has the potential to significantly alter the landscape of nicotine physical dependence, and local culture and other influences are likely associated with use patterns.

CORRESPONDENCE
Wiley D. Jenkins, PhD, MPH, Science Director, Population Health Science Program, Southern Illinois University School of Medicine, 201 E. Madison St., Springfield, IL 62794-9664; [email protected].

ABSTRACT

Background Electronic cigarettes (e-cigarettes) are often marketed as safe and effective aids for quitting cigarette smoking, but concerns remain that use of e-cigarettes might actually reduce the number of quit attempts. To address these issues, we characterized the utilization and demographic correlates of dual use of e-cigarettes and traditional cigarettes (referred to here as simply “cigarettes”) among smokers in a rural population of Illinois.

Methods The majority of survey participants were recruited from the 2014 Illinois State Fair and from another event—the Springfield Mile (a motorcycle racing event)—in Springfield, Ill. Survey questions explored participant demographics and cigarette and e-cigarette use history.

Results Of 201 total cigarette smokers, 79 smoked only tobacco cigarettes (smokers), while 122 also used e-cigarettes (dual users). Dual users did not differ significantly from smokers in gender, age, income, or education. Compared to smokers, dual users were more likely to smoke within 30 minutes of awakening (odds ratio [OR]=3.3; 95% confidence interval [CI], 1.8-6.3), but did not smoke more cigarettes per day or perceive a greater likelihood of quit success. Non-white dual users smoked fewer cigarettes per day than smokers. In addition, 79.5% of all dual users reported that they were using e-cigarettes to quit smoking or reduce the number of cigarettes smoked, and white respondents were 6 times more likely than non-whites to use e-cigarettes for ‘trying to quit smoking’ (OR=6.0; 95% CI, 1.1-32.9). Males and respondents with lower income were less likely to say they were using e-cigarettes to reduce the number of cigarettes smoked than females or participants with higher income (OR=0.2; 95% CI, 0.1-0.8 and OR=0.1; 95% CI, 0.0-0.5, respectively).

Conclusions E-cigarettes may significantly alter the landscape of nicotine physical dependence, and local influences likely are associated with use patterns. Future research should continue to examine whether dual use of traditional and electronic cigarettes impacts smoking cessation, and clinicians should be aware that local norms may create differences from national level data.

Approximately 21% of US adults use tobacco products at least occasionally.¹ Although smoking prevalence has declined in recent years (from 21% in 2005 to 18% in 2013), it remains high among certain groups (eg, males and those with a high school education or less).² As we know, the health burden of smoking—as a cause of death from cancer, pulmonary disease, and heart disease—is substantial,^3,4 and rural areas experience a significantly higher prevalence of smoking compared to urban areas.^2,5,6

However, it is unknown if the context and habits surrounding tobacco use in rural and/or Midwestern areas are similar to those of urban or nationally-representative populations. For example, while many urban residents may encounter a multitude of media messages encouraging smoking cessation resulting in less community acceptance of smoking, rural residents may be exposed to substantially fewer messages (eg, no city bus signs, billboards, subway posters, etc.) and the community may be more accommodating and tolerant of smoking.

Do e-cigarettes increase cigarette smoking?

Two-thirds of physicians report being asked about e-cigarettes by their patients, and one-third recommend using them as a smoking cessation aid.

Public health professionals are concerned about the increased use of e-cigarettes, particularly among young people, and whether this use increases the likelihood that individuals will start smoking tobacco cigarettes.⁷(Throughout this paper, we will use “cigarettes” and “smoking” to refer to the use of traditional tobacco cigarettes.) A recent study found that adolescents who used electronic nicotine delivery systems were twice as likely as non-users to have tried cigarettes in the past year.⁸

An onslaught of advertising. There are also concerns that e-cigarettes may serve to ‘renormalize’ nicotine addiction, in part through large-scale advertising, which was seen by nearly 70% of the participants in the 2014 National Youth Tobacco Survey.⁹ Largely as a result of that advertising, e-cigarette sales exceed $1.7 billion in the United States alone.¹⁰ With 15% of all US adults having ever tried electronic nicotine delivery systems and more than half (52%) of smokers having done so, questions regarding their health impact cannot be taken lightly.¹¹

Do e-cigarettes help people quit smoking? E-cigarettes are often marketed as a safe and effective means for quitting cigarette smoking.^12-14 (See "E-cigarettes: How "safe" are they?") Nearly two-thirds of physicians report being asked about e-cigarettes by their patients and approximately one-third of physicians recommend using them as a smoking cessation aid.¹⁵

Claims regarding the usefulness of e-cigarettes in smoking cessation, however, have not been substantiated by high-quality randomized controlled trials (RCTs). In fact, no RCTs have shown them to be safer or more effective than cessation treatments currently approved by the US Food and Drug Administration.^16,17

Two studies reflect the conflicting data that are currently available. One small study found intensive e-cigarette users were 6 times more likely than non-users/triers to report successful smoking cessation.¹⁸ However, researchers surveying callers of a cigarette quit line found that smokers who used e-cigarettes (dual users) were less likely to quit smoking than non-users.¹⁹

The lack of good-quality data substantiates the concern that dual use might discourage quitting by normalizing cigarette use and reducing perceptions of harm.^20,21 Dual use may also hamper smoking cessation efforts by increasing nicotine physical dependence and associated withdrawal symptoms when trying to quit.²² And finally, dual use may expose users to more carcinogens and toxins than those who use only one product, and the average number of cigarettes smoked per day may be significantly higher among dual users.²³

Unique demographic factors at work? Finally, the social and community context within which smoking occurs, and the prevalence of smoking-associated demographic risk factors, may vary significantly between rural and urban areas and between seemingly similar rural areas.^24-27 Few studies have examined differences in e-cigarette use between rural and urban areas. Those that have are contradictory, reporting that rural residents use e-cigarettes both more and less than their urban peers,^28,29 but many of these studies were conducted outside the United States, where the context and norms associated with smoking and e-cigarette use likely vary.

For these reasons, we sought to examine e-cigarette use among residents of Illinois, the nation’s fifth largest state and one with a rural population exceeding 1.5 million.³⁰ We compared dual users of e-cigarettes and cigarettes to smokers of cigarettes only in terms of demographic characteristics, nicotine physical dependence, and smoking cessation beliefs, and explored dual smokers' reasons for using both types of cigarettes.

MATERIALS AND METHODS

Dual users were no more likely than smokers to have attempted to quit smoking within the past year.

A survey was fielded during August and September 2014 in Springfield, Ill. To obtain responses, a booth was set up at both the Illinois State Fair and the Springfield Mile (a motorcycle racing event), and participants were recruited via direct solicitation by project staff. This was supplemented by an email invitation to all employees of the Southern Illinois University School of Medicine. The 2 venues and the email strategy were chosen because they draw from a large area of central and southern Illinois and were convenient to the location of the study team. Individuals were eligible to participate if they were ≥18 years of age and used any tobacco product or e-cigarettes. Survey elements were derived from 2 national surveys of health and behavior—the Minnesota Adult Tobacco Survey 2010³¹ and the Brief Smoking Consequences Questionnaire-Adult.³²

Survey questions assessed cigarette use, nicotine physical dependence, social norms, perceived risks and benefits, and smoking cessation beliefs and behaviors. Questions were slightly reworded to address not only the use of traditional cigarettes, but the use of e-cigarettes, as well. Ultimately, each participant answered a similarly-worded set of questions for both regular and e-cigarettes. Dual use of cigarettes and e-cigarettes was also assessed. Participants self-reported all data and survey responses on an electronic tablet and received a $10 (cash or gift card) incentive. This project was reviewed and approved by the Springfield Committee for Research Involving Human Subjects.

Stratification of results. Race was dichotomized into white and non-white. Education was stratified into 3 categories: up to and including high school graduation, some college but not a Bachelor’s degree, and Bachelor’s degree and above. Income was divided as being ≤$20,000 or >$20,000, and age was split into 2 groups by the median value. Analyses included descriptions of participant demographics, dual use status, measures of nicotine physical dependence, quit attempts, and e-cigarette use motivations. Bivariate relationships between dual use status and demographic characteristics, nicotine physical dependence, and smoking cessation beliefs were analyzed by chi-square (categorical variables) and ANOVA (continuous/Likert variables).

Multivariable logistic regression modeling of the demographic variables and dual use status (cigarette smoker only vs dual user) was performed to predict 3 factors: number of cigarettes smoked per day (≤10 vs 11+); time to first cigarette (≤30 vs 31+ minutes from waking); and perceived likelihood of quit attempt success (very/somewhat likely vs very/somewhat unlikely). Multivariable models examining the reasons for dual use included the demographic, nicotine physical dependence, and cessation belief items described previously.

RESULTS

Dual users were approximately 3 times more likely than smokers to smoke their first cigarette within 30 minutes of waking.

Of 309 total survey participants (Fair=288; Race=12; Email=9), there were 235 current cigarette smokers consisting of 79 who smoked only cigarettes (smokers); 122 who used both cigarettes and e-cigarettes (dual users); and 34 former e-cigarette users. Only smokers and dual users were included in this analysis (N=201, although for the purposes of TABLE 1, N=200 or 199 because at least one participant did not provide answers to all of the questions). Approximately 51% of the smokers were male, 78% were white, 12% were 4-year college graduates, and 57% reported incomes >$20,000. The mean age was 37.7 years (SD=14.4); 50% of respondents were <35 years of age. Dual users did not vary significantly from smokers in terms of gender, age, education, or income (all P>.05). However, a greater proportion of whites vs non-whites were dual users (54.9% vs 42.3%; P=.035).

Click here to see an enlarged version of the table.

No big quit differences. Bivariate analyses revealed that dual users were no more likely than smokers to have attempted to quit smoking within the past year (X²=2.3; P=.14), consider quitting in the next one or 6 months (X²=1.1; P=.34), or differ in perceived likelihood of cessation success (X²=0.0; P=1.00). The proportion of dual users who smoked 11+ cigarettes per day did not differ from that of cigarette smokers for the group as a whole or when the group was stratified by gender, income, education, or age. However, among non-whites, dual users smoked fewer cigarettes than cigarette smokers (TABLE 1).

Predicting physical dependence. Significant differences also were observed regarding the timing of the first cigarette of the day, with dual users approximately 3 times more likely than smokers to smoke within 30 minutes of awakening (80% vs 54.4%; OR=3.3; 95% CI, 1.8-6.3), and this difference was upheld among males, females, whites, those with an income >$20,000, those with a high school education or less and those with some college education, and age >34 years. There was no association, however, between dual use and perceived likelihood of quit success.

We then performed multivariable logistic modeling on dual users to determine which variables might predict 3 measures of physical dependence: number of cigarettes smoked per day (≤10 vs 11+), time between waking and smoking the first cigarette of the day (≤30 vs 31+ minutes), and perceived likelihood of cessation success (TABLE 2). Male gender (OR=3.4; 95% CI, 1.8-6.5) and white race (OR=4.4; 95% CI, 1.9-10.1) were significant for predicting smoking 11+ cigarettes a day, while dual use status was insignificant (P=.104). Regarding time to first cigarette, only dual use was significant (OR=3.1; 95% CI, 1.6-5.9), with dual users approximately 3 times more likely than smokers to have their first cigarette within 30 minutes of waking. No variables were significant in predicting perceived likelihood of quit success.

Reasons for dual use. We examined reasons for dual use with the question: Do you use e-cigarettes to reduce your regular tobacco use? Here, 79.5% of smokers reported using e-cigarettes to quit smoking or reduce the number of cigarettes smoked.

A multivariable polynomial logistic regression that included only dual users was performed to examine which variables might predict use for tobacco cessation (“trying to quit smoking”) vs reduction in smoking intensity (“trying to reduce the number of regular cigarettes I smoke per day”) vs no change (“use the same amount of tobacco as always”) (TABLE 2). Whites were approximately 6 times more likely than non-whites to indicate they engage in dual use to try to quit smoking (OR=6.0; 95% CI, 1.1-32.9). Males and people with lower incomes were much less likely to indicate they engaged in dual use to try to reduce the number of regular cigarettes smoked than females or those with higher incomes (OR=0.2; 95% CI, 0.1-0.8 and OR=0.1, 95% CI, 0.0-0.5, respectively). No other demographic variables or measures of nicotine physical dependence were significantly different between dual users and smokers.

Click here to see an enlarged version of the table.

DISCUSSION

Dual use was associated with a shorter time to first cigarette, but not a greater number of cigarettes smoked or perceived ability to successfully quit smoking.

E-cigarettes are used by approximately half of smokers (52%), which is much higher than that reported by Delnevo, et al, in their analysis of the National Health Interview Study.³³ There, prevalence of dual use of both cigarettes and e-cigarettes ranged from 3.4% to 12.7%. This substantial difference raises important questions regarding study population characterization. Were participants in our study representative of central Illinois, state fair attendees, or the agricultural profession? Further work to identify this group with an increased propensity for dual use will assist clinicians in developing appropriate intervention strategies.

Dual use in our study did not vary by many customary demographic variables. Nor was it associated with different rates of past or future quit attempts or perceived ability to successfully quit if quitting was attempted. These factors—high rates of dual use and insignificant effect on quit attempts—may have implications for local physicians counseling patients who smoke.

In our study, the majority of smokers already use e-cigarettes, and this does not seem to increase their ability/likelihood to quit smoking. Further, dual use did not seem to be associated with overall cigarette consumption; males and white participants smoked more cigarettes than females and non-whites. But dual use was associated with a measure of increased nicotine physical dependence (earlier first cigarette of the day). As a result, physicians may want to think twice before recommending e-cigarette use as a means of smoking cessation.

In addition to the high prevalence of e-cigarette use among smokers, a number of other interesting findings surfaced that run counter to some of the current literature. First, dual users are no more likely than smokers to have tried to quit in the past or to try to quit in the future.^21,22,34 It could be that for the relatively small geographical area from which our participants were recruited (central Illinois; ~77% of participants from Sangamon County alone), the local context and culture of smoking differs from that associated with participants in other studies, who were mostly recruited from national and regional online surveys. However, there is no a priori reason to suspect Sangamon County is especially different, as it is quite similar to Illinois as a whole by many measures (eg, percentage rural: 14.1% vs 11.5%; percentage black (only): 12.4% vs 14.7%; education to at least a Bachelor’s degree: 33.0% vs 31.9%; and median household income: $55,565 vs $57,166).³⁰

While we found that dual users did have one measure of increased nicotine physical dependence, the total number of cigarettes consumed per day was not significantly different from that of smokers.^23-25 This is contrary to another study of nicotine physical dependence, but, unlike that study, we did not assess length of time of concurrent use.³⁵ There is much uncertainty surrounding the issue of nicotine physical dependence and e-cigarette use, largely because the level of nicotine delivered by various e-products varies significantly.³⁶

Cross-sectional nature, small sample size limit utility of data

There are significant limitations to this study, including the cross-sectional nature of the data, the small sample size, the use of self-report, and the limited scope of recruitment. The relatively small sample size limits our ability to observe small differences and effect sizes. However, small differences often lack practical significance. Finally, participation was limited to those attending a state fair or a local sporting event and those employed by a local medical school. Thus, the results may not be generalizable to populations outside central Illinois. On the other hand, the very low income sample recruited from the Midwestern US, which is underrepresented in prior e-cigarette research, might represent some of the strengths of this work.

Future investigations. Future studies should more closely examine e-cigarette use prevalence on smaller geographic scales and especially in rural areas where there is a paucity of research. As the majority of our respondents came from a single county in central Illinois, one has to ask the questions, “Is this a ‘hot spot’ for e-cigarette use?" And "Do other rural areas experience similar use?” It may be important to know if national surveys are sensitive enough to observe significant local variations. Research also should examine how e-cigarette use and the influence of local culture vary across wider areas.

Several specific areas of study would help to inform policy and intervention development. For example, is tobacco cigarette quit success impacted by concurrent e-cigarette use? While our study showed no difference in past or possible future quit attempts among dual users as compared with smokers, we did not assess actual quit success, and multiple participants in our study anecdotally described using e-cigarettes to successfully quit smoking.

In the end, the rapid increase in the use of e-cigarettes has the potential to significantly alter the landscape of nicotine physical dependence, and local culture and other influences are likely associated with use patterns.

CORRESPONDENCE
Wiley D. Jenkins, PhD, MPH, Science Director, Population Health Science Program, Southern Illinois University School of Medicine, 201 E. Madison St., Springfield, IL 62794-9664; [email protected].

FLORENCE, ITALY – Influenza vaccination of heart failure patients cut their rate of hospitalization for cardiovascular disease by nearly a third during the year following vaccination in a study of more than 59,000 British heart failure patients.

Influenza vaccination of heart failure patients also cut their rate of hospitalization for respiratory infections by a statistically significant 16% during the year following vaccination, Dr. Kazem Rahimi said at a meeting held by the Heart Failure Association of the ESC.

Mitchel L. Zoler/Frontline Medical News

“In the absence of randomized trials, this [observational] study of 59,202 heart failure patients provides the most compelling evidence to date for the protective effect of influenza vaccination on hospital admissions,” said Dr. Rahimi, a cardiologist and epidemiologist who is deputy director of the George Institute for Global Health at the University of Oxford (England).

The analysis also showed that influenza vaccination of heart failure patients had no significant effect on all-cause hospitalizations.

Dr. Rahimi and his associates analyzed electronic health records from primary and secondary care settings in England during 1990-2013, from which they identified 59,202 heart failure patients with records for at least 1 year of influenza vaccination and at least 1 year without vaccination. The patients averaged 75 years old and were divided equally among women and men.

To control for potential confounding factors, they used a self-control model in which hospitalizations for each heart failure patient during the year following an influenza vaccination were compared with an adjacent year for that same patient when no vaccination occurred.

The results showed that the incidence of hospitalizations for cardiovascular diseases fell by a statistically significant 30% in the year following an influenza vaccination, compared with one or more adjacent years without vaccination. The protection again hospitalization was strongest during the second month following vaccination and then gradually waned over the ensuing year; by about 10 months following vaccination the protection effect had disappeared.

The study also looked at influenza vaccine uptake by heart failure patients through the 24-year period examined. During that time, the vaccination uptake rate rose from a low of less than 10% in 1990 to a peak rate of just over 60% in 2006, after which the rate gradually declined to a rate of just under 50% in 2013. Dr. Rahimi attributed the rise in uptake during the period from 1990 to 2006 in part to incentives that primary care physicians in England began receiving to administer influenza vaccine to their patients. “Higher uptake of annual vaccination in heart failure patients may help alleviate the burden of influenza-related hospital admissions,” he said.

Dr. Rahimi had no disclosures.

[email protected]

On Twitter @mitchelzoler

FLORENCE, ITALY – Influenza vaccination of heart failure patients cut their rate of hospitalization for cardiovascular disease by nearly a third during the year following vaccination in a study of more than 59,000 British heart failure patients.

Influenza vaccination of heart failure patients also cut their rate of hospitalization for respiratory infections by a statistically significant 16% during the year following vaccination, Dr. Kazem Rahimi said at a meeting held by the Heart Failure Association of the ESC.

Mitchel L. Zoler/Frontline Medical News

“In the absence of randomized trials, this [observational] study of 59,202 heart failure patients provides the most compelling evidence to date for the protective effect of influenza vaccination on hospital admissions,” said Dr. Rahimi, a cardiologist and epidemiologist who is deputy director of the George Institute for Global Health at the University of Oxford (England).

The analysis also showed that influenza vaccination of heart failure patients had no significant effect on all-cause hospitalizations.

Dr. Rahimi and his associates analyzed electronic health records from primary and secondary care settings in England during 1990-2013, from which they identified 59,202 heart failure patients with records for at least 1 year of influenza vaccination and at least 1 year without vaccination. The patients averaged 75 years old and were divided equally among women and men.

To control for potential confounding factors, they used a self-control model in which hospitalizations for each heart failure patient during the year following an influenza vaccination were compared with an adjacent year for that same patient when no vaccination occurred.

The results showed that the incidence of hospitalizations for cardiovascular diseases fell by a statistically significant 30% in the year following an influenza vaccination, compared with one or more adjacent years without vaccination. The protection again hospitalization was strongest during the second month following vaccination and then gradually waned over the ensuing year; by about 10 months following vaccination the protection effect had disappeared.

The study also looked at influenza vaccine uptake by heart failure patients through the 24-year period examined. During that time, the vaccination uptake rate rose from a low of less than 10% in 1990 to a peak rate of just over 60% in 2006, after which the rate gradually declined to a rate of just under 50% in 2013. Dr. Rahimi attributed the rise in uptake during the period from 1990 to 2006 in part to incentives that primary care physicians in England began receiving to administer influenza vaccine to their patients. “Higher uptake of annual vaccination in heart failure patients may help alleviate the burden of influenza-related hospital admissions,” he said.

Dr. Rahimi had no disclosures.

[email protected]

On Twitter @mitchelzoler

FLORENCE, ITALY – Influenza vaccination of heart failure patients cut their rate of hospitalization for cardiovascular disease by nearly a third during the year following vaccination in a study of more than 59,000 British heart failure patients.

Influenza vaccination of heart failure patients also cut their rate of hospitalization for respiratory infections by a statistically significant 16% during the year following vaccination, Dr. Kazem Rahimi said at a meeting held by the Heart Failure Association of the ESC.

Mitchel L. Zoler/Frontline Medical News

“In the absence of randomized trials, this [observational] study of 59,202 heart failure patients provides the most compelling evidence to date for the protective effect of influenza vaccination on hospital admissions,” said Dr. Rahimi, a cardiologist and epidemiologist who is deputy director of the George Institute for Global Health at the University of Oxford (England).

The analysis also showed that influenza vaccination of heart failure patients had no significant effect on all-cause hospitalizations.

Dr. Rahimi and his associates analyzed electronic health records from primary and secondary care settings in England during 1990-2013, from which they identified 59,202 heart failure patients with records for at least 1 year of influenza vaccination and at least 1 year without vaccination. The patients averaged 75 years old and were divided equally among women and men.

To control for potential confounding factors, they used a self-control model in which hospitalizations for each heart failure patient during the year following an influenza vaccination were compared with an adjacent year for that same patient when no vaccination occurred.

The results showed that the incidence of hospitalizations for cardiovascular diseases fell by a statistically significant 30% in the year following an influenza vaccination, compared with one or more adjacent years without vaccination. The protection again hospitalization was strongest during the second month following vaccination and then gradually waned over the ensuing year; by about 10 months following vaccination the protection effect had disappeared.

The study also looked at influenza vaccine uptake by heart failure patients through the 24-year period examined. During that time, the vaccination uptake rate rose from a low of less than 10% in 1990 to a peak rate of just over 60% in 2006, after which the rate gradually declined to a rate of just under 50% in 2013. Dr. Rahimi attributed the rise in uptake during the period from 1990 to 2006 in part to incentives that primary care physicians in England began receiving to administer influenza vaccine to their patients. “Higher uptake of annual vaccination in heart failure patients may help alleviate the burden of influenza-related hospital admissions,” he said.

Dr. Rahimi had no disclosures.

[email protected]

On Twitter @mitchelzoler