Abstract
INTRODUCTION: It remains unclear whether electronic cigarette (e-cigarette) use promotes persistent combustible tobacco use or smoking discontinuation over time. Alcohol use is associated with a greater risk of adverse health effects of tobacco, and higher likelihood of e-cigarette use, making drinkers a high-priority subpopulation. AIMS AND METHODS: This study examined longitudinal patterns of combustible tobacco and e-cigarette use over 24 months in young adult binge drinkers. A pooled dataset of 1002 (58.5% female; M age = 22.14) binge drinkers from the United States (60%) and Canada (40%) was used. The primary outcomes were past month combustible tobacco and e-cigarette use. Nicotine dependence was measured using the Fagerström Test of Cigarette Dependence. Alcohol severity was measured using the Young Adult Alcohol Consequences Questionnaire. Latent transition analysis (LTA) was used to identify patterns of cigarette smoking and e-cigarette use over 24 months. RESULTS: The LTA yielded a four-class solution: (1) e-cigarettes-only users (prevalence over time: 7.75%-10.10%), (2) dual-product users (2.61%-9.89%), (3) combustible-only smokers (8.12%-20.70%), and (4) nonusers (61.66%-80.06%). Dual-product users predominantly transitioned to complete abstinence or exclusively e-cigarette use. In combustible-only smokers, the most common transition was to abstinence, followed by persistence of combustible-only status. At 24 months, 63% of e-cigarettes-only users transitioned to abstinence, with 37% continuing e-cigarettes-only use and 0% transitioning to dual or combustible cigarette use. CONCLUSIONS: Dual-product use in young adult binge drinkers was associated with discontinuation of combustible tobacco over time, and e-cigarette-only use was not associated with subsequent combustible tobacco use. IMPLICATIONS: These findings suggest that concurrent or exclusive e-cigarette use is not a risk factor for the persistence or development of combustible tobacco use in this subpopulation, with dual-product use reflecting a transitional pattern away from combustible use, toward discontinuation.