No evidence of differences in smoking levels, nicotine dependence, carbon monoxide or motivational indices between cigarette smokers and cigarette + e-cigarette dual users in two samples.

Concurrent use of electronic cigarettes (e-cigarettes) as an alternative source of nicotine may lead to lower smoke exposure, tobacco addiction and reinforcing value of conventional combustible cigarettes. In two different cohorts, we characterized smokers, dual cigarette/e-cigarette users, and e-cigarette-only users in terms of sociodemographic, motives and patterns of e-cigarette use. Differences in smoking-related characteristics and reinforcing value of cigarettes between smokers and e-cigarette dual users were also examined. Two cohorts comprising 339 community adults [Sample 1; aged 18-65] and 293 young adult binge drinkers [Sample 2; aged 19-24] were recruited in Hamilton, Ontario. All participants provided expired carbon monoxide (CO) samples and completed an assessment battery including the Fagerström Test of Nicotine Dependence (FTND), the Wisconsin Inventory of Smoking Dependence Motives (WISDM), and the Cigarette Purchase Task (CPT). In both samples, smoking rate, CO level, FTND, WISDM, and CPT responses did not significantly differ between smokers and dual users. Compared to e-cigarette-only individuals, dual users from the two cohorts reported a greater use of e-cigarettes for quitting smoking, but dual product consumers exhibited no significant differences in motivation for change relative to combustible-only smokers. Relative to smokers, e-cigarette dual users did not show lower levels of smoking, lower severity of cigarette addiction and reinforcing value of cigarettes in these samples. These findings suggest that concurrent e-cigarette use does not affect combustible tobacco use or motivation, or reduce its harms.
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