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.