Association of electronic cigarette use with subsequent initiation of tobacco cigarettes in US youths
Use of cigarettes by young people has fallen in recent years, but the number of US youths using e‑cigarettes has increased substantially. There are now concerns that the increased use of e‑cigarettes could lead to the normalisation of smoking among young people.
There is a growing body of evidence that e-cigarette use may be associated with initiation of cigarette smoking in young people, with a recent meta-analysis finding that young e-cigarette users were more than three times as likely to subsequently start smoking. Use of other non-cigarette tobacco products also increases the risk of smoking later in life; however, few studies compare the use of these products and e-cigarettes in the same population, making direct comparisons between different non-cigarette products more difficult. Furthermore, previous studies are also open to methodological limitations; therefore, the aggregate effect of such products on subsequent cigarette use remains uncertain.
For this study, data were obtained from waves 1–3 of The Population Assessment of Tobacco and Health (PATH) Study to assess the association of e-cigarettes and non-cigarette tobacco products (e.g. shisha, snuff, cigars) on subsequent cigarette use in young people.
The study was comprised of youths who completed questions on current and prior nicotine product use at three timepoints between 2013 and 2016. Analysis was restricted to those aged 12–15 who had never used any tobacco product at the first timepoint (N=6123, mean age = 13.4 years). Study participants were further subclassified into those at high risk and at low risk for smoking initiation, according to their responses to questions on prior substance use and attitudes towards cigarettes.
The study authors found that youths who used e-cigarettes as their first nicotine product were more than four times as likely to ever smoke cigarettes and nearly three times more likely to currently use cigarettes over two years of follow-up, compared with nicotine-naive individuals. Interestingly, prior non-cigarette tobacco product use was associated with a similar risk. In a subanalysis, the authors found that the association between e-cigarette use and subsequent cigarette smoking behaviours was particularly pronounced in youths that were at low risk for smoking initiation. It was estimated that a substantial proportion of new cigarette use and current cigarette use may be attributable to the use of e-cigarettes – more than non-cigarette tobacco products.
These results are consistent with other studies suggesting that the use of e-cigarettes and non-cigarette tobacco products is associated with increased cigarette smoking initiation and use in young people. These findings corroborate the arguments for strict regulation of youth access to e‑cigarettes and they also have implications for their marketing.