Cessation outcomes in adult dual users of e-cigarettes and cigarettes: the Population Assessment of Tobacco and Health cohort study, USA, 2013-2016.

OBJECTIVES: We examined the transitions of adult dual e-cigarette/cigarette users in the USA in relation to nicotine dependence (ND) symptoms, interest in quitting, and history of cardiovascular disease (CVD). METHODS: We used the Population Assessment of Tobacco and Health study Waves 1 and 3 (2013-2016) in a longitudinal analysis of adults (≥ 18 years). Dual past-month users of e-cigarettes/cigarettes were identified from Wave 1 and followed for tobacco use transitions 2 years later (Wave 3). RESULTS: Among 1870 adult dual users at Wave 1, 25.7% (95% CI 23.5-28.2) were dual users 2 years later, 12.1% (95% CI 10.6-13.7) reported no past-month tobacco use, 7.0% (95% CI 5.6-8.9) e-cigarette mono-use, and 55.2% (95% CI 52.4-58.0) cigarette mono-use. In the regression analysis, greater ND severity was associated with decreased relative risk of no past-month tobacco use (RRR 0.29; 95% CI 0.12-0.71). Interest in quitting and CVD factors were not associated with no past-month tobacco or e-cigarette mono-use. CONCLUSIONS: Dual users who are nicotine dependent are less likely to transition to cessation. To quit cigarette use, other cessation resources may be necessary to support the needs of cigarette smokers who use e-cigarettes, particularly those at risk of continuing cigarette smoking or those with smoking-related illnesses.