Electronic cigarettes, sometimes referred to as e-cigarettes, are battery-powered devices that vaporize a liquid solution that users inhale — the process is often called “vaping.” The solutions generally contain nicotine and are available in a wide range of flavors. Because users inhale heated vapor rather than smoke, e-cigarettes have been marketed as a healthier alternative to cigarette smoking, which is the number one cause of preventable death in the United States.
Because of their growing popularity, e-cigarettes are a burgeoning topic among tobacco control, harm-reduction and addictions researchers. While e-cigarettes appear to offer substantially lower exposure to toxic compounds than conventional cigarettes, the health impacts are difficult to evaluate, and remain thus far unclear. Research on the effectiveness of e-cigarettes as smoking cessation (quitting) tools is sparse, and there is evidence that some smokers use them to avoid smoking restrictions.
As of 2014, e-cigarettes are not regulated unless they are marketed for therapeutic purposes. The FDA has proposed extending its current regulatory authority to include e-cigarettes; if this does happen, manufacturers would be required to disclose product ingredients and prohibited from marketing new products without FDA review, and from selling or marketing to youth. In the meantime, 22 states have imposed laws that limit youth access to e-cigarettes, and 12 regulate indoor e-cigarette use. Manufacturers would further be prohibited from advertising their products using health claims unless the FDA confirms that the products are beneficial to the public health, which would include an evaluation of potential harm to users and nonusers.
Individual-level harm potential and harm reduction
At present, the health effects of e-cigarettes tend to be weighed in relationship to those of conventional cigarettes. For example, 2013 research conducted by the Roswell Park Cancer Institute found that toxicity levels in e-cigarette vapor were between 9 and 450 times lower than those found in cigarette smoke. However, a 2014 literature review by the FDA’s Center for Tobacco Products identified several difficulties in assessing e-cigarettes’ toxicity: First, data on human exposure to compounds and toxicants in e-cigarettes is sparse. Second, users may employ them in different ways, puffing with varying frequency or duration, and may also smoke conventional cigarettes, all of which can substantially change exposure levels. Third, research suggests that nicotine-delivery levels can vary significantly even within the same brand of e-cigarette. Another 2014 literature review by the Center for Tobacco Products found a great deal of variability in the toxic components in e-cigarettes’ solutions and vapor.
Because e-cigarettes were introduced to the U.S. market only in 2007, their long-term health impacts have not been studied, nor have the effects of secondhand exposure to e-cigarette vapor. The Centers for Disease Control and Prevention (CDC) reports 1,700 cases of accidental exposure to e-cigarettes between 2010 and 2013, with the majority occurring in children under six.
Effectiveness as a cessation tool
E-cigarettes may have the potential to function as a cessation tool, and have been compared to methadone in the context of heroin addiction. In a 2013 study in The Lancet, e-cigarettes showed modest promise: After six months, participants using e-cigarettes had a slightly higher abstinence rate than for those using the nicotine patch. Real-world effectiveness studies in the United States have not been published, but a study of English smokers attempting to quit found that those who used e-cigarettes were more likely to succeed than those who used nicotine-replacement therapy or who attempted to quit unaided. However, those who used e-cigarettes in their cessation efforts were also more likely to be of a higher socioeconomic status, which is associated with greater success in smoking cessation.
In the U.S., researchers from the Cancer Prevention and Control Program at the University of Hawaii Cancer Center have found that smokers who use e-cigarettes as a cessation aid are more likely to be younger, non-white, higher income, and have lower levels of nicotine dependence, shorter smoking history and a greater number of lifetime quit attempts than smokers who use pharmaceutical nicotine replacement therapy. Other studies have shown that e-cigarette use does not predict smoking cessation.
As the market for e-cigarettes has grown, manufacturers have been aggressively using the Web, social media and television to promote their products. Research published in 2014 in Nicotine & Tobacco Research found that e-cigarette advertising was the most widely circulated of all non-combustible tobacco products. A 2014 content analysis of e-cigarette websites by the San Francisco Center for Tobacco Control Research and Education showed that the majority (95%) made explicit or implicit health claims: 64% mentioned smoking cessation, and 88% noted they can be used anywhere, with 71% explicitly talking about the circumvention of clean indoor air laws.
Researchers at South Korea’s Hanyang University analyzed 365 YouTube e-cigarette-related videos and 85% were sponsored by marketers. Researchers at the Institute for Health Research and Policy at the University of Illinois at Chicago found that among 73,672 e-cigarette tweets, 90% were by marketers, and 40% were by users with e-cigarette keywords in their Twitter handles — yet these users made up only 2% of Twitter users who tweeted about e-cigarettes. A 2014 examination of Nielsen data published in Pediatrics showed a 256% increase in exposure to televised e-cigarette advertisements between 2011 and 2013. Exposure largely took place on cable television.
E-cigarettes and youth
According to the CDC, e-cigarette use appears to be on the rise among U.S. adolescents. A 2014 study from New York University found that 50% of U.S. adolescents are aware of e-cigarettes, and of these 13% had tried one, and 4% were regular users to some degree. A 2014 article in the Journal of the American Medical Association and 2014 study in Nicotine & Tobacco Research both found that e-cigarette use was associated with a greater likelihood of intending to smoke conventional cigarettes.
A 2014 study by the Yale School of Medicine found that adolescents who use e-cigarettes were more likely to smoke hookahs and “blunts” than those who smoked conventional cigarettes. Among adolescents who smoke conventional cigarettes, concurrent e-cigarette use has not been shown to be associated with a desire to quit. A 2014 report by members of the U.S. Congress found that e-cigarette marketing targets youth, either through attendance at youth-oriented events, advertising during radio and television programs with youth audiences, or flavors that appeal to teens.
The following is a recommended selection of studies on e-cigarettes:
“Electronic Cigarettes: Human Health Effects”
Callahan-Lyon, Priscilla. Tobacco Control, May 2014, Vol. 23, No. 2. doi: 10.1136/tobaccocontrol-2013-051470.
Abstract: “With the rapid increase in use of electronic nicotine delivery systems (ENDS), such as electronic cigarettes (e-cigarettes), users and non-users are exposed to the aerosol and product constituents. This is a review of published data on the human health effects of exposure to e-cigarettes and their components…. Scientific evidence regarding the human health effects of e-cigarettes is limited. While e-cigarette aerosol may contain fewer toxicants than cigarette smoke, studies evaluating whether e-cigarettes are less harmful than cigarettes are inconclusive. Some evidence suggests that e-cigarette use may facilitate smoking cessation, but definitive data are lacking. No e-cigarette has been approved by FDA as a cessation aid. Environmental concerns and issues regarding non-user exposure exist. The health impact of e-cigarettes, for users and the public, cannot be determined with currently available data.”
“Tobacco Control Policy and Electronic Cigarettes”
Chaloupka, Frank J. Journal of the American Medical Association Pediatrics, July 2014, Vol. 168, No. 7, 601-2. doi: 10.1001/jamapediatrics.2014.349.
Excerpt: “As ENDS [electronic nicotine delivery systems] use has grown in the United States, federal, state, and local governments have struggled with how to treat ENDS under existing tobacco control policies and/or with developing and implementing new policies. In part, this struggle reflects the desire to maximize the use of ENDS as a smoking cessation tool, while at the same time preventing youths from starting with ENDS and moving on to conventional cigarettes. While not harmless, moving current smokers from cigarettes to ENDS would almost certainly lead to significant reductions in the health and economic consequences of smoking. However, the high rates of use of both ENDS and conventional cigarettes among current ENDS users suggest that many are using them as a way to satisfy their nicotine addiction in venues where smoking is not allowed rather than as a means to quit smoking entirely, raising concerns that the public health impact of ENDS could be minimal.”
“E-cigarettes and Conventional Cigarette Use among U.S. Adolescents: A Cross-Sectional Study”
Dutra, Lauren M; Glantz, Stanton A. Journal of the American Medical Association Pediatrics, July 2014, Vol. 168, No. 7, 610-7. doi: 10.1001/jamapediatrics.2013.5488.
Abstract: “Cross-sectional analyses of survey data from a representative sample of U.S. middle and high school students in 2011 (n = 17 353) and 2012 (n = 22 529) who completed the 2011 and 2012 National Youth Tobacco Survey…. Use of e-cigarettes was associated with higher odds of ever or current cigarette smoking, higher odds of established smoking, higher odds of planning to quit smoking among current smokers, and, among experimenters, lower odds of abstinence from conventional cigarettes. Use of e-cigarettes does not discourage, and may encourage, conventional cigarette use among U.S. adolescents.”
“Electronic Cigarettes: Abuse Liability, Topography and Subjective Effects”
Evans, Sarah E; Hoffman, Allison C. Tobacco Control, May 2013, Vol. 23. No. 2. doi: 10.1136/tobaccocontrol-2013-051489.
Abstract: “A total of 15 peer-reviewed articles regarding behavioural use and effects of e-cigarettes published between 2010 and 2014 were included in this review. Abuse liability studies are limited in their generalisability. Topography (consumption behaviour) studies found that, compared with traditional cigarettes, e-cigarette average puff duration was significantly longer, and e-cigarette use required stronger suction. Data on e-cigarette subjective effects (such as anxiety, restlessness, concentration, alertness and satisfaction) and withdrawal suppression are limited and inconsistent. In general, study data should be interpreted with caution, given limitations associated with comparisons of novel and unusual products, as well as the possible effects associated with subjects’ previous experience/inexperience with e-cigarettes.”
“Safety Evaluation and Risk Assessment of Electronic Cigarettes as Tobacco Cigarette Substitutes: A Systematic Review”
Farsalinos, Konstantinos E.; Polosa, Riccardo. Therapeutic Advances in Drug Safety, April 2014, Vol. 5, No. 2, 67-86. doi: 10.1177/2042098614524430.
Abstract: “Electronic cigarettes are a recent development in tobacco harm reduction. They are marketed as less harmful alternatives to smoking. Awareness and use of these devices has grown exponentially in recent years, with millions of people currently using them. This systematic review appraises existing laboratory and clinical research on the potential risks from electronic cigarette use, compared with the well-established devastating effects of smoking tobacco cigarettes. Currently available evidence indicates that electronic cigarettes are by far a less harmful alternative to smoking and significant health benefits are expected in smokers who switch from tobacco to electronic cigarettes. Research will help make electronic cigarettes more effective as smoking substitutes and will better define and further reduce residual risks from use to as low as possible, by establishing appropriate quality control and standards.”
“E-cigarettes: A Scientific Review”
Grana, Rachel; Benowitz, Neal; Glantz, Stanton. Circulation, May 2014, Vol. 129, No. 19, 1972-86. doi: 10.1161/circulationaha.114.007667.
Excerpt: “Although data are limited, it is clear that e-cigarette emissions are not merely “harmless water vapor,” as is frequently claimed, and can be a source of indoor air pollution. Smoke-free policies protect nonsmokers from exposure to toxins and encourage smoking cessation. One hundred percent smoke-free policies have larger effects on consumption and smoking prevalence, as well as hospital admissions for myocardial infarction, stroke, and other cardiovascular and pulmonary emergencies, than weaker policies. Introducing e-cigarettes into clean air environments may result in population harm if use of the product reinforces the act of smoking as socially acceptable or if use undermines the benefits of smoke-free policies.”
“A Longitudinal Analysis of E-cigarette Use and Smoking Cessation”
Journal of the American Medical Association Internal Medicine, May 2014, Vol. 174, No. 5, 812-3. doi: 10.1001/jamainternmed.2014.187.
Discussion: “Consistent with the only other longitudinal population-level study with one-year follow-up, we found that e-cigarette use by smokers was not followed by greater quitting, or reduction in consumption one year later. We lacked detailed data on e-cigarette use characteristics, such as frequency, duration, use patterns or motivation for use. Our smoking cessation data were self-reported. Although 13.5% of the sample quit, the low numbers of e-cigarette users in this sample (n=88), particularly e-cigarette users who quit (n=9), may have limited our statistical power to detect a significant relationship between e-cigarette use and quitting. Nonetheless, our data add to the current evidence that e-cigarettes may not increase rates of smoking cessation. Regulations should prohibit advertising that claims or suggests e-cigarettes are effective smoking cessation devices until claims are supported by scientific evidence.”
“Non-cigarette Tobacco Products: What Have We Learnt and Where Are We Headed?”
O’Connor, Richard J. Tobacco Control, March 2012, Vol. 21, No. 2, 181-90. doi: 10.1136/tobaccocontrol-2011-050281.
Abstract: “A wide variety of non-cigarette forms of tobacco and nicotine exist, and their use varies regionally and globally. Smoked forms of tobacco such as cigars, bidis, kreteks and waterpipes have high popularity and are often perceived erroneously as less hazardous than cigarettes, when in fact their health burden is similar. Smokeless tobacco products vary widely around the world in form and the health hazards they present, with some clearly toxic forms (e.g., in South Asia) and some forms with far fewer hazards (e.g., in Sweden). Nicotine delivery systems not directly reliant on tobacco are also emerging (e.g., electronic nicotine delivery systems). The presence of such products presents challenges and opportunities for public health. Future regulatory actions such as expansion of smoke-free environments, product health warnings and taxation may serve to increase or decrease the use of non-cigarette forms of tobacco. These regulations may also bring about changes in non-cigarette tobacco products themselves that could impact public health by affecting attractiveness and/or toxicity.”
“Electronic Cigarettes and Vaping: A New Challenge in Clinical Medicine and Public Health: A Literature Review”
Palazzolo, Dominic L. Frontiers in Public Health, November 2013, Vol. 1, 56. doi: 10.3389/fpubh.2013.00056.
Abstract: “Given the controversial nature of e-cigarettes and vaping, how should medical care providers advise their patients? To effectively face this new challenge, health care professionals need to become more familiar with the existing literature concerning e-cigarettes and vaping, especially the scientific literature…. A search of the most current literature using the PubMed database dating back to 2008, and using electronic cigarette(s) or e-cigarette(s) as key words, yielded a total of 66 highly relevant articles. These articles primarily deal with (1) consumer-based surveys regarding personal views on vaping, (2) chemical analysis of e-cigarette cartridges, solutions, and mist, (3) nicotine content, delivery, and pharmacokinetics, and (4) clinical and physiological studies investigating the effects of acute vaping. When compared to the effects of smoking, the scant available literature suggests that vaping could be a ‘harm reduction’ alternative to smoking and a possible means for smoking cessation, at least to the same degree as other Food and Drug Administration-approved nicotine replacement therapies. However, it is unclear if vaping e-cigarettes will reduce or increase nicotine addiction. It is obvious that more rigorous investigations of the acute and long-term health effects of vaping are required to establish the safety and efficacy of these devices; especially parallel experiments comparing the cardiopulmonary effects of vaping to smoking. Only then will the medical community be able to adequately meet the new challenge e-cigarettes and vaping present to clinical medicine and public health.”
“E-cigarette Awareness, Use, And Harm Perceptions In U.S. Adults”
Pearson, Jennifer L; Richardson, Amanda; Niaura, Ray S; Vallone, Donna M; Abrams, David B. American Journal of Public Health, September 2012, Vol. 102, No. 9, 1758-66. doi: 10.2105/AJPH.2011.300526.
Abstract: “We estimated e-cigarette (electronic nicotine delivery system) awareness, use, and harm perceptions among U.S. adults…. In the online survey, 40.2% (95% confidence interval [CI] = 37.3, 43.1) had heard of e-cigarettes, with awareness highest among current smokers. Utilization was higher among current smokers (11.4%; 95% CI = 9.3, 14.0) than in the total population (3.4%; 95% CI = 2.6, 4.2), with 2.0% (95% CI = 1.0, 3.8) of former smokers and 0.8% (95% CI = 0.35, 1.7) of never-smokers ever using e-cigarettes. In both surveys, non-Hispanic Whites, current smokers, young adults, and those with at least a high-school diploma were most likely to perceive e-cigarettes as less harmful than regular cigarettes. Conclusions: Awareness of e-cigarettes is high, and use among current and former smokers is evident. We recommend product regulation and careful surveillance to monitor public health impact and emerging utilization patterns, and to ascertain why, how, and under what conditions e-cigarettes are being used.”
“Four Hundred and Sixty Brands of E-cigarettes and Counting: Implications for Product Regulation”
Zun, Shu-Hong; Sun, Jessica Y; Bonnevie, Erika; Cummins, Sharon E; Gamst, Anthony; et al. Tobacco Control, July 2014, Vol. 23, No. 3, ii3-9. doi: 10.1136/tobaccocontrol-2014-051670.
Abstract: “E-cigarettes are largely unregulated and internet sales are substantial. This study examines how the online market for e-cigarettes has changed over time: in product design and in marketing messages appearing on websites…. Results: By January 2014 there were 466 brands (each with its own website) and 7764 unique flavours. In the 17 months between the searches, there was a net increase of 10.5 brands and 242 new flavours per month. Older brands were more likely than newer brands to offer cigalikes (86.9% vs. 52.1%, p<0.01), and newer brands more likely to offer the more versatile eGos and mods (75.3% vs. 57.8%, p<0.01). Older brands were significantly more likely to claim that they were healthier and cheaper than cigarettes, were good substitutes where smoking was banned and were effective smoking cessation aids. Newer brands offered more flavours per brand (49 vs. 32, p<0.01) and were less likely to compare themselves with conventional cigarettes. Conclusions: The number of e-cigarette brands is large and has been increasing. Older brands tend to highlight their advantages over conventional cigarettes while newer brands emphasise consumer choice in multiple flavours and product versatility. These results can serve as a benchmark for future research on the impact of upcoming regulations on product design and advertising messages of e-cigarettes.”
Keywords: research roundup, e-cigarettes, tobacco, cessation, youth, marketing, addiction, consumer affairs