Vaping in Adolescents May Have Little Effect on Subsequent Cigarette Smoking

Vaping behavior has little effect on whether adolescents in the US who have never smoked cigarettes will begin smoking cigarettes, or whether adolescents who do begin smoking cigarettes continue to smoke, according to study findings published in the Journal of the American Medical Association Network Open.

It is unclear whether vaping leads to long-term cigarette use. Investigators therefore sought to assess the association of vaping among adolescents and their smoking of cigarettes on an ongoing basis approximately 2 years after starting to vape. 

The researchers conducted a cohort study using data from the national longitudinal Population Assessment of Tobacco and Health (PATH) Study. The analysis included 8671 PATH participants 12 to 17 years of age who had never used cigarettes prior to October 2015, some of whom began vaping between October 2015 and October 2016 (wave 3). Participants were followed through wave 4 (December 2016 to January 2018) and wave 5 (December 2018 to November 2019).  Cigarette smoking was assessed in PATH via audio computer-assisted self-interviewing and computer-assisted personal interviewing. Multivariable logistic regressions were used for the current analysis, with the primary outcomes of interest being the number of participants who initiated cigarette smoking in wave 4 and the number who then continued cigarette smoking in wave 5.

Overall, among participants (55% aged 12 to 14 years; 49% female; 51% non-Hispanic White), 4% (362 participants) began cigarette smoking during wave 4 and less than 3% (218 participants) continued smoking during wave 5 (218/362 participants [60%]). Investigators noted that the adjusted odds ratio (OR) for those in wave 3 continuing to smoke during wave 5 among those who had ever vaped vs those who had not vaped was 1.81 (95% CI, 1.03-3.18). Notably, this odds ratio controlled for multiple covariates  that included mental health measures, cigarette susceptibility, other substance use, environmental factors, and socio-demographics.

In evaluating how many participants in wave 3 continued smoking (with “continued smoking” defined as past 12-month use during wave 4 and past 30-day use) in wave 4 and into wave 5, investigators found this occurred in 6% of those who had ever vaped (95% CI, 4.5%-8.0%) vs 1% of those who had never vaped (95% CI, 0.8%-1.3%). In evaluating longer term continued smoking at wave 5 (defined as past 12-month cigarette use during wave 4 and continuous smoking with established use in wave 5), investigators found that this occurred in less than 4% of those who had ever vaped (95% CI, 2.5%-5.1%) vs 0.5% of those who had never vaped (95% CI, 0.3%-0.7%).

Overall, the absolute risk of continued smoking in those who vaped was 2.07% (95% CI, 1.01%-3.13%); vs 1.19% (95% CI, 0.79%-1.59%) in those who had never vaped; the adjusted risk difference of 0.88% (95% CI, -0.13 to 1.89 percentage points) was not significant. The researchers found that other factors associated with continued smoking included internalizing and externalizing problems, cigarette susceptibility, alcohol and cannabis use within the past 12 months, ever having used other tobacco products, peer cigarette smoking, family tobacco use and secondhand smoke, school grades, race and ethnicity.

Significant study limitations include the possibility of response bias among self-reporting teenagers.

“The minor risk differences in continued smoking among baseline e-cigarette users and nonusers, together with the small magnitude of absolute risks for both groups, suggest that regardless of baseline e-cigarette use, few adolescents were likely to report continued smoking after initiation,” investigators concluded. They wrote “In general, in this cohort study, regardless of e-cigarette use status, few cigarette-naive adolescents (4.1%) initiated cigarette smoking and even fewer (≤2.5%) continued to smoke at all in 3 years.”