For example, one of the major problems in some of the previous survey studies of electronic cigarettes (the ones cited by Stan Glantz, for example) is that they fail to control for a major confounder: the level of a smoker's addiction to smoking and motivation to quit. Some of the studies that Glantz has cited to show that e-cigarettes are ineffective for smoking cessation compare users of e-cigarettes and non-users of e-cigarettes. In two of these studies, those who did not use e-cigarettes had higher quit rates.

The paper defends its ethical standards by arguing that it "was consistent with Facebook's Data Use Policy, to which all users agree prior to creating an account on Facebook, constituting informed consent for this research."

The authors write: "Consistent with the only other longitudinal population-level study with 1-year follow-up that we are aware of, we found that e-cigarette use by smokers was not followed by greater rates of quitting or by reduction in cigarette consumption 1 year later."

LAST：china alibaba supplier ce4 cartomizer |NEXT：2014 portable design ego zipper case Ego carrying Case for ecig start kits