Tobacco vs. electronic cigarettes: absence of harm reduction after six years of follow-up.

OBJECTIVE: Information on the long-term safety of electronic cigarettes (e-cig) is still limited. We report the results after six years of follow-up of the first observational study assessing e-cig long-term effectiveness and safety. PATIENTS AND METHODS: Participants were adults who smoked ≥1 tobacco cigarette/day (tobacco smokers); or used any type of e-cig inhaling ≥50 puffs weekly (e-cig users); or used both (dual users). Participants were contacted directly or by phone and/or internet interviews. Hospital discharge abstract data and carbon monoxide level tests were also used. RESULTS: Data were available for 228 e-cig users (all ex-smokers), 469 tobacco smokers, 215 dual users. A possibly smoking-related disease (PSRD) was recorded in 90 subjects (9.9%); 11 deceased (1.2%). No differences were observed across groups in PSRD rates, with minor changes in self-reported health. Among e-cig users, 64.0% remained tobacco abstinent. Dual users and tobacco smokers did not significantly differ in the rate of cessation of tobacco (38.6% vs. 33.9%, respectively) and all products (23.7% vs. 26.4%). A comparable decrease in daily cigarettes was also observed. 39.5% of the sample switched at least once (tobacco smokers: 15.1%; dual users: 83.3%). CONCLUSIONS: After six years, no evidence of harm reduction was found among e-cig or dual users. The complete switch to e-cig might support tobacco quitters remain abstinent, but the use of e-cig in addition to tobacco did not improve smoking cessation or reduction.