Association of e-cigarette use with tobacco cessation in youth cigarette smokers enrolled in a youth quitline: a prospective study (oral and abstract)

Abstract

<p><strong>Significance</strong> Evidence on the role of electronic cigarette (e-cigarette) use in youth cigarette smokers interested in tobacco cessation has remained limited. We examined the association of current e-cigarette use with tobacco abstinence in youth cigarette smokers attending a cessation service.</p><p><strong>Methods</strong> The HKU Youth Quitline is a community- based tobacco cessation service offering multi-sessions telephone counselling to tobacco users aged 25 years or younger in Hong Kong. We analyzed data from 1,295 current (past 30-day) cigarette smokers (80.8% male; 32.3% aged <18 years; 64% smoked daily) who enrolled in the service from December 2016 to February 2022. The exposure variable was current (past 30-day) use of e-cigarettes at baseline. The main outcome was biochemically validated tobacco abstinence at 6 months after baseline. Covariates included sex, age, cigarette dependence (assessed by the Fagerström Test for Nicotine Dependence), any previous quit attempt, and risk of depression (assessed by the Center for Epidemiological Studies Depression). Poisson regression with robust variance was used to estimate the relative risk (RR) of abstinence outcomes by baseline e-cigarette use. Participants with missing outcomes were assumed to have no change in tobacco use behaviors from baseline.</p><p><strong>Results</strong> At baseline, 252 of 1295 (19.5%) participants currently smoked e-cigarettes. The most common reasons for initiating e-cigarette use among 241 current users were “curiosity” (37.8%), followed by “influenced by peers/others” (30.3%), “to quit or reduce smoking” (27.8%), and “flavoring” (13.3%). Compared with non-users, current e-cigarettes users were more likely to be underaged (<18) smokers (P<0.001), female (P=0.04), full-time students (P=0.001), smoke daily (vs non-daily) (P=0.049), and at risk of depression (P=0.001). At 6-month follow-up (retention rate=69.9%), current e-cigarette use at baseline was not associated with biochemically validated tobacco abstinence (7.1% vs 9.3%; adjusted RR 0.76; 95% CI 0.44-1.31; P=0.32). Self-reported 7-day point prevalent abstinence at 3 months (20.0% vs 20.6%) and 6 months (20.2% vs 21.1%) were similar between current e-cigarette users and non-users. Subgroup analyses showed that the associations did not differ by sex, age groups (<18 vs ≥18), cigarette dependence (mild vs moderate/heavy) and between daily and non-daily cigarette smokers and those with or without risk of depression (all P for interaction>0.05).</p><p><strong>Conclusions</strong> We did not find evidence that current e-cigarette use was prospectively associated with tobacco cessation in youth cigarette smokers enrolled in a youth cessation service.</p>