Does Electronic Cigarette Use Predict Abstinence from Conventional Cigarettes among Smokers in Hong Kong?

To investigate the effects of ever use of electronic cigarettes (ECs), many of which lack nicotine, on abstinence from convention cigarettes among Hong Kong adult smokers. We collected data from 956 daily smokers in 2014-2015 regarding ever EC use and smoking behaviors at baseline, any and past 30-day EC use at the 3-month follow-up. Outcomes measured at 6 months included past 7-day point prevalence abstinence (PPA), biochemically validated quitting, smoking reduction (≥50% from baseline) and cessation attempt. Logistic regression yielded adjusted odds ratios (AOR) for quitting in relation to EC use, adjusting for socio-demographic characteristics and smoking profile. Complete case, missing observation as smoking and propensity score analyses were conducted. By complete case, ever EC use at baseline did not predict self-reported PPA (AOR 0.99, 95% CI 0.57-1.73), biochemically validated quitting (AOR 1.22, 95% CI 0.64-2.34), cessation attempt (AOR 0.74, 95% CI 0.48-1.14), or smoking reduction (AOR 0.89, 95% CI 0.54-1.47). EC use during the first 3 months did not predict quitting (AOR 1.02, 95% CI 0.22-4.71). Similar results were observed for missing observations as smoking and propensity score analyses. Any use of ECs, many of which lack nicotine, did not predict smoking abstinence among Hong Kong adult smokers.