- FAMRI Center
Meta-analysis of all available population studies continues to show smokers who use e-cigs less likely to quit smoking
There are now 11 pubilshed studies that compare quitting smoking among smokers who use e-cigarettes compared to smokers who do not use e-cigarettes (counting the two analyses Lois Biener did, one for intense e-cigarette users and one for intermittent e-cigarette users, as separate estimates).
Using all these estimates in a random effects meta-analysis shows a significant drop in quitting with an odds ratio of 0.723 (with a 95% confidence interval ["margin of error"] of 0.531 to 0.983). Thus, smokers who use e-cigarettes are about 30% less likely to quit smoking than smokers who do not use-ecigarettes.
An interesting detail is that there is significant heterogeunity among the studies (p<.001). This heterogenuity is due to the Brown/West study; removing it from the analysis makes the heterogenuity test non-significant (p=0.092). Removing this study does not change the overall conclusion; the pooled estimate of the effect of e-cigarettes on quitting just gets a little bigger (OR = 0.623. 95% CI 0.509 to 0.763, p,.001), but it does raise the question of what is different about the Brown/West study.