E-cigarettes and Smoking Cessation in Real-World and Clinical Settings: A Systematic Review and Meta-Analysis
Lancet Respir Med 2016; Published Online; January 13, 2016; http://dx.doi.org/10.1016/ S2213-2600(15)00521-4
Sara Kalkhoran, Stanton A Glantz
Findings 38 studies (of 577 studies identified) were included in the systematic review; all 20 studies with control
groups (15 cohort studies, three cross-sectional studies, and two clinical trials) were included in random effects metaanalysis
and sensitivity analyses. Odds of quitting cigarettes were 28% lower in those who used e-cigarettes compared
with those who did not use e-cigarettes (odds ratio [OR] 0・72, 95% CI 0・57–0・91). Association of e-cigarette use with
quitting did not significantly differ among studies of all smokers using e-cigarettes (irrespective of interest in quitting
cigarettes) compared with studies of only smokers interested in cigarette cessation (OR 0・63, 95% CI 0・45–0・86 vs
0・86, 0・60–1・23; p=0・94). Other study characteristics (design, population, comparison group, control variables, time
of exposure assessment, biochemical verification of abstinence, and definition of e-cigarette use) were also not
associated with the overall effect size (p≥0・77 in all cases).
Interpretation As currently being used, e-cigarettes are associated with significantly less quitting among smokers.