Electronic cigarettes, nicotine use trends and use initiation ages among US adolescents from 1999 to 2018

Abstract

Background and Aims Recent nicotine use trends raise concerns that electronic cigarettes (ECs) may act as a gateway to cigarettes among adolescents. The aims of this study were to examine prevalence trends of exclusive EC use, exclusive cigarette use and dual use to determine the corresponding ages of initiation and to investigate hypothetical trends in total nicotine use and cigarette use in the absence of ECs among US adolescents. Design Observational study using data from the National Youth Tobacco Survey (NYTS) to statistically model trends in the prevalences of each user group and their initiation ages. Projections from counterfactual models based on data from 1999 to 2009 (before EC introduction) were compared with actual trends based on data from 1999 to 2018. Rigorous error analyses were applied, including Theil proportions. Setting USA. Participants and measurements Adolescents aged 12–17 years who were established exclusive cigarette users (≥ 100 cigarettes smoked and ≤ 100 days vaped), established exclusive EC users (< 100 cigarettes smoked and > 100 days vaped) and established dual users (≥ 100 cigarettes smoked and > 100 days vaped), based on cumulative life‐time exposure (n ≈ 12 500–31 000 per wave). Findings Exclusive cigarette use prevalence declined from 1999 to 2018, while exclusive EC use and dual use prevalences increased since their introduction in 2009. The age of cigarette initiation began a slight increase after 2014, whereas the age for EC use remained approximately constant and was higher than that of cigarettes. The counterfactual comparison results were consistent with ECs not increasing the number of US adolescent nicotine users, and in fact diverting adolescents from cigarettes. Conclusions Electronic cigarettes may have offset conventional smoking among US adolescents between 2010 and 2018 by maintaining the total nicotine use prevalence and diverting them from more harmful conventional smoking. Additionally, electronic cigarette users appear to initiate at older ages relative to conventional smokers, which is associated with lower risk.

Increasing similarities between young adults’ smoking and snus use in Norway: a study of the trends and stages of smoking and snus epidemic from 2010 to 2018

“…However, the latter findings are mixed [8]. Reports on whether other less harmful products such as e-cigarettes acts as gateways to smoking are also mixed [32][33][34], indicating a need for more research on whether less harmful products, including snus, may act as a gateway to smoking.…”

The greater use of flavoured snus among ever-smokers versus never-smokers in Norway

“…Anyway, if a causal association between snus use and subsequent smoking really exists, ecological trend data indicates that this association must have been dwarfed by other factors protecting against smoking uptake. Because at the population level, an inverse correlation between snus use and smoking has been observed among young adults in Norway [10], and recently also between vaping and smoking in the USA [55] and in New Zealand [56]. Thus, lending support to the "diversion theory" hypothesizing that snus/e-cigarettes might deter cigarette smoking by diverting "high-risk" individuals to snus/e-cigarettes from combustible cigarettes.…”

Commentary on Foxon & Selya (2020): Social gradients in long‐term health consequences of cigarette use—will adolescent e‐cigarette use follow the same trajectory?

“…Foxon and Selya (2020) document that the prevalence of exclusive e‐cigarette use among United States (US) youth has substantially increased around 2010, whereas exclusive combustible cigarette (cigarette) use continuously declined [1]. This evidence is consistent with e‐cigarette use diverting youth from cigarette use, which suggests a net public health benefit, insofar as e‐cigarettes are less harmful, and increased prevalence does not generate cigarette users later [1]. However, asking how harmful e‐cigarettes are requires an interrogation of what harms, inflicted on whom and, specifically, on which social class?…”