E-cigarettes (electronic nicotine delivery systems) emerged in the U.S. market in 2007 and have rapidly grown in popularity.78 E-cigarettes, or e-vaporizers, are devices that heat a liquid containing solvents, flavors, and often nicotine.79 Users inhale the resulting vapor. A variety of designs are available, some mimicking the look of traditional cigarettes. More than 7,000 flavors are available for e-cigarettes,80 some of which are especially appealing to youth. Many convenience stores, drug stores, grocery stores, and other physical and online retail outlets sell e-cigarettes, although as of mid December, 2019, it is illegal to sell any nicotine or tobacco products to people under 21.237 Some convenience stores and drugstore chains have also stopped selling e-cigarettes to promote public health.
In 2013, more than one third of cigarette smokers said they had ever used e-cigarettes.78 According to data from the 2014 Tobacco Products and Risk Perceptions Survey, current cigarette smokers had a greater likelihood of using e-cigarettes. This analysis found that half of cigarette smokers had ever used an e-cigarette and 20.7 percent currently used these devices. However, approximately 10 percent of adults who used e-cigarettes had never smoked previously.81 Data from the 2014 National Health Interview Survey indicated that 0.4 percent of adults who have never smoked and 0.8 percent of former smokers (abstinent 4 or more years) currently use e-cigarettes.82 The survey also found that 13 percent of daily e-cigarette users were former smokers who quit during the past year.82
As with cigarette use, e-cigarette use is higher among people with mental health conditions—with 3.1 percent currently using compared with 1.1 percent of those without mental illness.83 It is also a concern that pregnant women are using e-cigarettes, as nicotine exposure during periods of developmental vulnerability (including prenatal development) has adverse health consequences.84
Users report the belief that e-cigarette products are less harmful than traditional cigarettes,85 and many report using them to help quit smoking traditional cigarettes. While it is not yet clear if e-cigarettes are effective smoking cessation aids, the devices are sometimes marketed for this purpose86 (see "Are e-cigarettes useful for smoking cessation?"). Some research suggests that older adults use these devices as a tobacco substitute, although not always as a cessation method.87 Users also cite convenience and being conscientious towards others as reasons for using these products.88
Reports of Deaths Related to Vaping
The Food and Drug Administration has alerted the public to thousands of reports of serious lung illnesses associated with vaping, including dozens of deaths. They are working with the Centers for Disease Control and Prevention (CDC) to investigate the cause of these illnesses. Many of the suspect products tested by the states or federal health officials have been identified as vaping products containing THC, the main psychotropic ingredient in marijuana. Some of the patients reported a mixture of THC and nicotine; and some reported vaping nicotine alone. While the CDC and FDA continue to investigate possible other contributing substances, CDC has identified a thickening agent—Vitamin E acetate—as a chemical of concern among people with e-cigarette or vaping associated lung injuries. They recommend that people should not use any product containing Vitamin E acetate, or any vaping products containing THC; particularly from informal sources like friends, family, or in-person and online dealers. They also warn against modifying any products purchased in stores, or using any vaping products bought on the street. People, including health professionals, should report any adverse effects of vaping products. The CDC has posted an information page for consumers.
How does the federal government regulate e-cigarettes?
The U.S. Food and Drug Administration (FDA), which regulates cigarettes, tobacco, and smokeless tobacco, gained the authority in 2016 to also regulate electronic nicotine delivery systems (such as e-cigarettes and vape pens), all cigars, hookah (waterpipe) tobacco, pipe tobacco, and nicotine gels, among other tobacco products. Under the new regulations, e-cigarette manufacturers must list ingredients. In December 2019, the federal government raised the legal minimum age of sale of tobacco products from 18 to 21 years, and in January 2020, the FDA issued a policy on the sale of flavored vaping cartridges
- Is it true that e-cigarettes are safer than traditional cigarettes?
It is likely that, on balance, e-cigarettes are safer than traditional cigarettes from the standpoint of physical health. However, as discussed above, the nicotine in e-cigarettes can cause addiction and neurocognitive impairments.
Although for regulatory purposes e-cigarettes are classified as “tobacco products,” they do not contain tobacco or produce the same toxic combustion products, like tar, that cause lung cancer and other diseases in users and people exposed to secondhand smoke. However, the vapor from e-cigarettes typically contains nicotine and a range of other chemicals.89 Because these products are relatively new, evidence on the short-term effects of exposure to e-cigarette aerosols is limited, and very little is known about the long-term health effects.
A review of recent literature found that some of the chemicals in e-cigarette liquid, propylene glycol and glycerol, cause throat irritation and coughing.89 Other research suggests that vapor exposure may be linked with impaired lung function.89 Chemical analyses that compare the profiles of electronic and traditional cigarettes have suggested that e-cigarettes have a reduced carcinogenic profile and impart a lower potential for disease.90 However, toxicants, carcinogens, and metal particles have been detected in the liquids and aerosols of e-cigarettes, and it is currently unclear what risk they pose with repeated use.91 As with traditional cigarettes, use of e-cigarettes involuntarily exposes nonusers to secondhand and thirdhand aerosol.91
The research on secondhand exposure to the aerosol from e-cigarettes is limited, but one study found that fine particulate matter concentrations during an indoor event in a large room with e-cigarette smokers were higher than those reported previously in venues that allowed cigarette smoking.88 An in vitro study showed that exposing lung tissues and cells to e-cigarette liquid induced increased inflammatory responses and oxidative stress markers.92 Another study that analyzed e-cigarette flavorings found that 39 of the 51 flavors tested positive for diacetyl, a chemical associated with an irreversible obstructive lung disease called bronchiolitis obliterans. Other chemicals, 2,3-pentanedione and acetoin, associated with severe respiratory diseases among exposed people, were also found in many e-cigarette flavorings.89
The amount of nicotine in e-cigarette fluid varies. Some research has found that e-cigarettes deliver less nicotine on average than traditional cigarettes,93 but that users may change puffing patterns to compensate. Inexperienced e-cigarette users take in modest nicotine concentrations, but those who regularly use these devices adjust their puffing to consume similar levels of the drug as with traditional cigarettes.93–95 Newer e-cigarette devices can deliver substantial amounts of nicotine, and some users are able to get nicotine at levels similar to96 or even greater than a traditional cigarette.97,98 One study found equivalent levels of nicotine's major metabolite in the blood of smokers who use traditional and e-cigarettes.89 Thus, all the nicotine-related concerns of traditional cigarettes—addiction, effects on cognitive function, and effects on prenatal development—apply to e-cigarettes as well.
Risks of E-Cigarettes to Children
Young children may accidentally ingest the concentrated nicotine (which often contains flavors) in e-cigarette liquid.91 The Centers for Disease Control and Prevention recently compared calls to poison centers in the United States related to human exposures to e-cigarettes and traditional cigarettes. The study found that between September 2010 and February 2014, the proportion of e-cigarette calls among all cigarette-related calls increased from 0.3 percent to 41.7 percent.99 Most of the e-cigarette exposures were among children under the age of 5 years (51.1 percent) and people over age 20 (42.0 percent), whereas almost all traditional cigarette exposure calls involved young children.99 Data indicated that a greater proportion of e-cigarette exposure calls (57.8 percent) resulted in adverse health effects than traditional cigarette exposure (36.0 percent). These adverse health effects included vomiting, nausea, and eye irritation.99
- Are e-cigarettes useful for smoking cessation?
Some research suggests e-cigarettes may help people quit smoking cigarettes, while other data suggest that they can impede quitting and that they may open the door to traditional cigarette use for people who might not otherwise try them. Thus, much more research is needed on this question.
One review of recent studies suggested that the likelihood of quitting cigarettes was 28 percent lower among individuals who used e-cigarettes compared with those who did not use these devices, regardless of whether users were interested in quitting.100 Research from the United Kingdom suggests that among smokers who continue to use traditional cigarettes, daily use of e-cigarettes was associated with increased attempts to quit and cut back, but not with success.101 However, another analysis estimated that, in England, 16,000 smokers were able to quit in 2014 who would not have quit if e-cigarettes had not been available.102 A review and meta-analysis also suggested that using e-cigarettes for a minimum of 6 months was associated with quitting or reducing the number of cigarettes used.103
- E-cigarettes and Teens
National survey data suggest that e-cigarettes were the most commonly used nicotine delivery product among youth.12–17 A review of the literature found that up to 20 percent of adolescents who currently use e-cigarettes had never smoked a traditional cigarette.87
A major concern is that e-cigarettes’ flavors, design, and marketing particularly appeal to youth,91 and that by introducing young people to nicotine and glamorizing a smoking-like behavior, e-cigarettes could open the door to cigarette use in a population that is particularly vulnerable to addiction and that has seen historic declines in cigarette smoking.
Some research indicates that e-cigarette use may lead to the use of traditional cigarettes among adolescents and young adults.104 According to data from the 2012 NYTS, youth who had only used e-cigarettes reported an increased intention to smoke traditional cigarettes compared with peers who had never used these devices. The survey found no link between e-cigarette use and intention to quit smoking among youth who were current smokers, indicating that this age group does not see these products primarily as smoking-cessation aids.105 A longitudinal cohort study of 16- to 26-year-olds who had never smoked traditional cigarettes found that 2.3 percent (16 participants) used e-cigarettes at the start of the study. After a one-year follow-up, approximately 69 percent (11 of 16) of these participants progressed to smoking traditional cigarettes compared to 18.9 percent (128 of 678) among those who never used an e-cigarette.106 Another study found that past-month e-cigarette use predicted future cigarette use, but that past-month cigarette use did not predict future e-cigarette use.107
Many young people report experimenting with e-cigarettes out of curiosity, because the flavors appeal to them, or because of peer influences.108 The majority of youth who reported e-cigarette use in one study had friends who used these products. Almost half of adolescents who used e-cigarettes said that they did not believe these products were associated with health risks.109 Young people also perceived e-cigarettes as easy to obtain, "cool," and a better alternative to cigarettes because they were thought to be healthier and could be used anywhere. Among youth who stopped using e-cigarettes, the major underlying reasons were health concerns, loss of interest, high cost, bad taste, and view of e-cigarettes as less satisfying than cigarettes.108