Association between e-cigarette use and future combustible cigarette use: Evidence from a prospective cohort of youth and young adults, 2017–2019

•Young people who use e-cigarettes are more likely to smoke than those who do not.•Modern vape devices do not decrease the risk of transition to combustible tobacco.•JUUL use has similar risk of transition to combustible as use of non-JUUL devices.•Young vapers were more likely than older vapers to continue vaping one year later. A surge in popularity of e-cigarettes prompts concern given the association between e-cigarettes and future cigarette use. However, much of the evidence for this association comes from early, less efficient, and lower nicotine e-cigarettes than are available and widely used now. The goal of this study was to examine the relationship between e-cigarette use in 2018 and subsequent smoking initiation and continued e-cigarette use. Participants included members of a national longitudinal panel of youth and young adults aged 15–27 who, in 2017, reported never having used a nicotine containing product (n = 3360). Logistic regression analyses assessed associations between participants’ self-reported ever e-cigarette use in 2018 and ever cigarette use, current cigarette use, and current e-cigarette use in 2019, after controlling for demographic and psychosocial variables. Compared with those who still had never used an e-cigarette, those who reported ever e-cigarette use in 2018 had significantly higher odds of ever cigarette use (aOR = 7.29, 95% CI [4.10, 12.97]), current cigarette use (aOR = 8.26, 95% CI [3.17, 21.53]), and current e-cigarette use (aOR = 9.70, 95% CI [6.41, 14.69]) one year later in 2019. These findings show that the pod mod style, high nicotine containing e-cigarettes subject young users to the same risks of transitioning to combustible cigarettes as their earlier, less efficient predecessors. Strong regulation of all nicotine products, including e-cigarettes, is needed to prevent the trajectory of e-cigarette to cigarette use among youth and young adults.