Is e-cigarette use in non-smoking young adults associated with later smoking? A systematic review and meta-analysis
Although this random effects meta-analysis of 17 observational studies (n=57,514) found evidence for an association between e-cigarette use among non-smokers and later smoking (adjusted OR 2.92, 95% CI: 2.30 to 3.71), there was high heterogeneity (I2=85%).
Source:
Tobacco Control
SPS commentary:
The authors note that despite the heterogeneity, all studies individually reported a positive association. Age contributed to the heterogeneity, with a stronger association observed in studies including those aged below 18 years. In addition the associations were stronger in UK studies, suggesting country-specific societal factors may be confounding the association. None of the studies included negative controls and much of the evidence has failed to consider nicotine content of e-cigarettes; it is therefore difficult to make conclusions about whether nicotine is the mechanism driving the observed association.
A ‘behind the headlines’ article on the NHS website discusses this study, as it was the focus of recent press reports.