Dependence on e-cigarettes and cigarettes in a cross-sectional study of US adults

Background and aims Cigarette smoking often results in nicotine dependence. With use of electronic cigarettes as an alternative source of nicotine, it is important to assess dependence associated with e-cigarette use. This study assesses dependence among current and former adult e-cigarette users on cigarettes and e-cigarettes, compared with dependence on cigarettes. Design Cross-sectional data from the Population Assessment of Tobacco and Health (PATH) study from 2013-2016. Psychometrically assessed dependence was compared for cigarettes and e-cigarettes among current and former exclusive and dual users of the products and among e-cigarette users who had and had not recently stopped smoking. Setting A population-based representative sample of US adults. Participants Participants were 13 311 US adults (18+) in Waves 1-3 of PATH reporting current established smoking, current use of e-cigarettes, or stopping use of either product in the past year who were administered dependence assessments for cigarettes and/or e-cigarettes. Measurements A 16-item scale assessing tobacco dependence (on a 1-5 scale), previously validated for assessment and comparison of dependence on varied tobacco products, including cigarettes and e-cigarettes, with a variation assessing residual dependence among users who stopped in the past year. Findings Among current users, dependence on e-cigarettes was significantly lower than dependence on cigarettes, in within-subjects comparisons among dual users of both e-cigarettes and cigarettes (1.58 [SE = 0.05] vs. 2.76 [0.04]), P < 0.0001), and in separate groups of e-cigarette users and cigarette smokers (1.95 [0.05] vs. 2.52 [0.02], P < 0.0001), and among both daily and non-daily users of each product. Among former users, residual symptoms were significantly lower for e-cigarettes than cigarettes, both among former dual users (1.23 [0.07] vs. 1.41 [0.06], P < 0.001) and among users of one product (1.28 [0.03] vs. 1.53 [0.03], P < 0.0001). The highest level of e-cigarette dependence was among e-cigarette users who had stopped smoking (2.17 [0.08]). Conclusion Use of e-cigarettes appears to be consistently associated with lower nicotine dependence than cigarette smoking.