E-cigarettes are beneficial in short term but longer forecast is uncertain, landmark US report findsBMJ 2018; 360 doi: https://doi.org/10.1136/bmj.k355 (Published 24 January 2018) Cite this as: BMJ 2018;360:k355
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Re: E-cigarettes are beneficial in short term but longer forecast is uncertain, landmark US report finds
Dyer’s ambitious review of such a large report (1) regarding the newly published and comprehensive National Academies of Sciences, Engineering, and Medicine (NASEM) scientific review of the “Public Health Consequences of E-Cigarettes (2) contains some, arguably, questionable interpretations of the review, and some important omissions.
Firstly, Dyer does not highlight, relating to exhaled “mainstream” e-cigarette aerosol (there is no sidestream emittance as there is with cigarettes), that the review states that:
“There is conclusive evidence that e-cigarette use increases airborne concentrations of particulate matter and nicotine in indoor environments compared with background levels.”
“The levels of both particulate matter and nicotine were higher in experiments with more than one vaper, and they were extremely high in studies of vaping conventions, where levels of particulate matter and nicotine concentrations were comparable to those founds in bars and nightclubs. Among the other constituents, two studies have detected airborne toluene and other VOCs in the air following vaping experiments. Total VOCs were markedly high and increased with increasing levels of vaping, during a vaping cloud competition, supporting that VOCs are released from the e-cigarettes into the environment during the exhalation of the e-cigarette aerosol. Overall, these exposure studies indicate that e-cigarette vaping contributes to some level of indoor air pollution, which, although lower than what has been observed from secondhand combustible tobacco cigarettes, is above the smoke-free level recommended by the U.S. Surgeon General and the WHO FCTC.”
Thus, clinically, the NASEM articulate that: “As with second hand smoke, children, pregnant women, the elderly, and patients with cardiorespiratory diseases may be at special risk. The e-cigarette convention studies also suggest that e-cigarette aerosol exposure could be substantial for workers in these venues, especially those who are exposed during multiple events.”
Interestingly, further, Dyer does not confirm, in relation to efficacy, that the NASEM state that “Overall, there is limited evidence that e-cigarettes may be effective aids to promote smoking cessation.” This fact, obviously, leaves clinicians practicing evidence-based medicine in a particularly awkward situation when it comes to discussing e-cigarettes with patients, and why the current advice from NICE (3) is that clinicians should inform people that, although “Some smokers have found them helpful to quit smoking cigarettes”, “there is currently little evidence on the long-term benefits or harms of these products.” Those, as the NASEM articulate, include crucial issues relating to, firstly, relapse rates, on which we have very little data, and secondly, e-cigarette efficacy relative to other quitting aids. As the review articulates:
“There is insufficient evidence from randomized controlled trials about the effectiveness of e-cigarettes as cessation aids compared with no treatment or to Food and Drug Administration–approved smoking cessation treatments.”
Indeed, the NASEM report states that there is ONLY “moderate evidence from randomized controlled trials that e-cigarettes with nicotine are more effective than e-cigarettes without nicotine for smoking cessation”, which is hardly reassuring.
In relation to the modelling projections that the report discusses, the paramount issue of relapse rates is not, unfortunately, mentioned by Dyer. The NASEM state that: “Under the assumption that the use of e-cigarettes increases the net cessation rate of combustible tobacco cigarette smoking among adults (i.e., the increase in permanent quitting offsets the potential relapsing of former smokers because of e-cigarettes), the modeling projects that use of these products will generate a net public health benefit, at least in the short run.”
Moreover, in the U.S., new CDC data (4) reveals, despite the acknowledged rapid increase in use of e-cigarettes over the last few years by adult smokers, and in contrast to the trend from 2005, that in “2016, the prevalence of current cigarette smoking among adults was 15.5%”, and that “no significant change has occurred since 2015 (15.1%) . . .” Thus, the CDC argues that: “Proven population-based interventions are critical to reducing the health and economic burden of smoking-related diseases”: currently, clearly, e-cigarettes have not been proven to be such. Could it be that the mass use of e-cigarettes is locking very many smokers into continued dual use with conventional cigarettes, for, as the CDC say elsewhere, “most adult e-cigarette users do not stop smoking cigarettes and are instead continuing to use both products” (5); and even one cigarette per day carries with it significant risks (6). It was also highlighted by a co-author of the report elsewhere that, under the worst assumptions, "the modelling projects a net public health loss" (7).
Dyer mentions, further, FDA Commissioner Scott Gottlieb, who has reportedly called the NASEM identified link between e-cigarette use and trying smoking in youth and young people: "troubling" (8). The link is, indeed, particularly troubling, considering a recent large meta-analysis (9) identified that 3 out of 5 people who experiment with one cigarette become, at least temporarily, daily smokers. Gottlieb also apparently proclaimed that: "We need to put novel products like e-cigarettes through an appropriate series of regulatory gates to fully evaluate their risks and maximize their potential benefits," (8), so, it still remains unclear as to exactly how the US approach to e-cigarettes will develop. Some influential organisations have taken a precautionary perspective on the report:
“Overall findings from the report suggest that regulation of e-cigarettes is critical for the protection of public health. Without FDA pre-market review of these products, there is no way for a consumer to reliably know what they are getting. It is also important to be very concerned about youth experimentation and uptake of ENDS products, the proliferation of flavors and highly appealing products such as JUUL, a product that now has roughly 50 percent of the e-cigarette market” (10).
For those unfamiliar with JUUL, it has been described as the “i-Phone of E-cigs” (11), and “discrete enough to use in class” (12). Intriguingly, further, the NASEM, as far as this author can observe, do not claim that e-cigarettes are 95% safer than cigarettes, as Public Health England and the Royal College of Physicians widely do. With the uncertainties observed in the report, it is incredible how such a claim can be scientifically substantiated.
All views are my own, and not necessarily those of my employer.
1) Dyer, O. E-cigarettes are beneficial in short term but longer forecast is uncertain, landmark US report finds. BMJ 2018;360:k355
2) National Academies of Sciences, Engineering, and Medicine. Public Health Consequences of E-Cigarettes. 2018. Available at: http://nationalacademies.org/hmd/reports/2018/public-health-consequences...
3) National Institute for Health and Care Excellence. 2017. Available at: http://data.parliament.uk/writtenevidence/committeeevidence.svc/evidence...
4) Jamal, A., et al. Current Cigarette Smoking Among Adults — United States, 2016. MMWR Morb Mortal Wkly Rep 2018;67:53–59. Available at: http://dx.doi.org/10.15585/mmwr.mm6702a1
5) Centre for Disease Control and Prevention. Electronic Cigarettes. Available at: https://www.cdc.gov/tobacco/basic_information/e-cigarettes/index.htm
6) Hackshaw, A., et al. Low cigarette consumption and risk of coronary heart disease and stroke: meta-analysis of 141 cohort studies in 55 study reports. BMJ 2018;360:j5855.
7) Ault, A. e-Cigarettes May Spark Smoking in Teens, Says NAS Report. Medscape. Available at: https://www.medscape.com/viewarticle/891710
8) WBIW.com Do E-Cigarettes Help Or Harm? Report Says Not Clear Yet. Available at: http://www.wbiw.com/state/archive/2018/01/do-e-cigarettes-help-or-harm-r...
9) Birge, Max., et al. "What proportion of people who try one cigarette become daily smokers? A meta analysis of representative surveys." Nicotine & Tobacco Research (2017).
10) Truth Initiative. New report shows that e-cigarettes can both harm and help the smoking epidemic. Available at: https://truthinitiative.org/news/new-report-shows-e-cigarettes-can-both-...
11) JUUL Vapor. Available at: https://www.juulvapor.com/
12) NPR.org Teenagers embrace Juul saying its discrete enoutg to vape in class. Available at: https://www.npr.org/sections/health-shots/2017/12/04/568273801/teenagers...
Competing interests: No competing interests