A Source of Bias in Studies of E-Cigarettes and Smoking Cessation

This is the authors' abstract. We don't add key points for this paper.

Kalkhoran et al.1 aim to assess the evidence for use of e-cigarettes as an effective aid to cigarette smoking cessation using data from the multiwave Population Assessment of Tobacco and Health (PATH) Study,2 a nationally representative U.S. cohort study. As they note, randomized controlled trials (RCTs) would provide the gold standard of causal evidence regarding the impact of e-cigarette use on smoking cessation but few have been conducted and none within the United States. Despite the strengths of RCTs, findings from RCTs are not without limitations. By design, RCTs use controlled settings with a selective population that is rarely...