A Longitudinal Analysis of Nicotine Dependence and Transitions From Dual Use of Cigarettes and Electronic Cigarettes: Evidence From Waves 1-3 of the PATH Study.

OBJECTIVE Electronic cigarettes (e-cigarettes) have gained popularity as a method to reduce conventional cigarette smoking, despite mixed evidence on their effectiveness. This study evaluates the relationship between overall and product-specific nicotine dependence and the transitions between dual use of cigarettes and e-cigarettes versus exclusive cigarette or e-cigarette use over time. METHOD This study used data from Waves 1-3 (2013-2016) of the Population Assessment of Tobacco and Health (PATH) Study. Weighted logistic regressions with person-level random effects tested relationships between nicotine dependence and dual versus exclusive use over time. Dual use transitions were then compared with the characteristics of e-cigarette devices used and reasons to use them. RESULTS Higher tobacco dependence was associated with becoming or remaining a dual user rather than remaining or becoming an exclusive user of cigarettes or e-cigarettes (p < .05). Higher e-cigarette dependence was associated with remaining or becoming an exclusive e-cigarette user. The number of days smoking cigarettes or using e-cigarettes in the past 30 days was also associated with greater odds of remaining or transitioning to exclusive use of that product (p < .05). Exclusive e-cigarette users tended to invest more financially in their devices and were more likely to report owning modifiable devices. CONCLUSIONS This study provides new evidence that established dual use and transitions to and from dual use are associated with higher tobacco dependence compared with remaining a cigarette- or e-cigarette-only user and that higher e-cigarette dependence is associated with becoming or remaining an exclusive user of e-cigarettes.