A critique of the US Surgeon General’s conclusions regarding e-cigarette use among youth and young adults in the United States of America

Abstract

Background: In December 2016, the Surgeon General published a report that concluded e-cigarette use among youth and young adults is becoming a major public health concern in the United States of America. Methods: Re-analysis of key data sources on nicotine toxicity and prevalence of youth use of e-cigarettes cited in the Surgeon General report as the basis for its conclusions. Results: Multiple years of nationally representative surveys indicate the majority of e-cigarette use among US youth is either infrequent or experimental, and negligible among never-smoking youth. The majority of the very small proportion of US youth who use e-cigarettes on a regular basis, consume nicotine-free products. The sharpest declines in US youth smoking rates have occurred as e-cigarettes have become increasingly available. Most of the evidence presented in the Surgeon General's discussion of nicotine harm is not applicable to e-cigarette use, because it relies almost exclusively on exposure to nicotine in the cigarette smoke and not to nicotine present in ecigarette aerosol emissions. Moreover, the referenced literature describes effects in adults, not youth, and in animal models that have little relevance to real-world e-cigarette use by youth. The Surgeon General's report is an excellent reference document for the adverse outcomes due to nicotine in combination with several other toxicants present in tobacco smoke, but fails to address the risks of nicotine decoupled from tobacco smoke constituents. The report exaggerates the toxicity of propylene glycol (PG) and vegetable glycerin (VG) by focusing on experimental conditions that do not reflect use in the real-world and provides little discussion of emerging evidence that e-cigarettes may significantly reduce harm to smokers who have completely switched. Conclusions: The U.S. Surgeon General's claim that e-cigarette use among U.S. youth and young adults is an emerging public health concern does not appear to be supported by the best available evidence on the health risks of nicotine use and population survey data on prevalence of frequent e-cigarette use. Nonetheless, patterns of e-cigarettes use in youth must be constantly monitored for early detection of significant changes. The next US Surgeon General should consider the possibility that future generations of young Americans will be less likely to start smoking tobacco because of, not in spite of, the availability of e-cigarettes.

Commentary on Seyla et al. (2018): Advantages in the consideration of causal mechanisms for studies of gateway e‐cigarette use

“…Longitudinal cohort studies (‘prospective studies’) are promising, because they can demonstrate whether and how trajectories of smoking initiation differ between e‐cigarette users and non‐users. However, there are difficulties in making causal inferences using this approach . Some of these, such as a lack of sufficient attention to measures of the type and intensity of cigarette use and e‐cigarette use , could potentially be overcome.…”

“…However, there are difficulties in making causal inferences using this approach . Some of these, such as a lack of sufficient attention to measures of the type and intensity of cigarette use and e‐cigarette use , could potentially be overcome. Nonetheless, never‐smokers who try e‐cigarettes are likely to be very different from never‐smokers who do not.…”

“…These studies may be better equipped to tease out subtle and temporally complex inter‐relationships between vaping and smoking. A clear focus upon the type and degree of e‐cigarette use and smoking would contrast with the relatively crude measures that are often employed . For example, there are few plausible causal mechanisms that would link brief experimentation or non‐nicotine vaping to smoking initiation.…”

Change and Continuity in Vaping and Smoking by Young People: A Qualitative Case Study of a Friendship Group

“…Quantitative surveys cannot, for the most part, explore these more nuanced aspects of ecigarette/vape use and yet these are precisely the domains that we need to better understand in order to develop evidence-based interventions aimed at reducing the use of these devices by non-smokers. Large scale social surveys of young people that report substantial increases in e-cigarette/vape use are often based on 'ever' or 'last 30 day' measures (27). However, survey work with young people have also shown that only a tiny proportion of ever users report frequent or current use of these devices (7,27,28,29,30,31).…”

“…Large scale social surveys of young people that report substantial increases in e-cigarette/vape use are often based on 'ever' or 'last 30 day' measures (27). However, survey work with young people have also shown that only a tiny proportion of ever users report frequent or current use of these devices (7,27,28,29,30,31). Quantitative surveys need measures that better capture the quantity and frequency of use of e-cigarette and vape devices and other important variables like nicotine content (11).…”