Tag Archives: vaping and smoking cessation

Peer review of: Linda Johnson et al. (Washington U med school), E-cigarette Usage Is Associated with Increased Past 12 Month Quit Attempts and Successful Smoking Cessation in Two U.S. Population-based Surveys, NTR 2018.

by Carl V Phillips

For an overview of this collection and an explanation of the format of this post, please see this brief footnote post.

The paper reviewed here is available at Sci-Hub. The paywalled link is here.

This collection will focus mainly on the misleading anti-THR papers produced by tobacco controllers. However, it is useful and important to provide reviews of potentially important paper that might be called pro-THR. This is one example of a paper that has gotten a lot of “ha, take that!”-toned traction.

If a “pro-THR” paper is tight, a review will provide a substantive endorsement, as positive reviews should do (but as the anonymous and secret — and presumptively poor-quality — journal reviews cannot do), as well as a signal boost. If a paper is useful but importantly flawed (as in the present case), the review can correct or identify the errors and focus attention on the defensible bits. And if the paper is fatally flawed, the review should point that out. Bad advice is still bad advice when it feels like it is “on your side”. Even when a paper basically only provides political ammunition and not advice, it is important to assess its accuracy. We are not tobacco controllers, after all, who just make up whatever claims seem to advance their political cause.


Johnson et al. use historical nationally-representative U.S. tobacco use data (NHIS from 2006 to 2016 and CPS over most of that period), for 25- to 44-year-olds, looking at the rate of smoking quit attempts and the association between vaping status and quit attempts or successful smoking abstinence. The authors report an unconditional increase in the population for both quit attempts (measured as a the rate of past-year incidence among people who smoke) and medium-term smoking abstinence. They also report a positive association between vaping and smoking quit attempts and abstinence at the individual level. They interpret their results as running contrary to the recent spate of “vapers are less likely to quit” claims, stating “These trends are inconsistent with the hypothesis that e-cigarette use is delaying quit attempts and leading to decreased smoking cessation.”

This is an overstatement, but the results do run contrary to the “vaping is keeping smokers from quitting” trope that the authors position their paper as a response to. This research clearly moves our priors a bit in the direction of “yes, vaping encourages people to quit smoking, and helps them do so.” Our priors only move “a bit” because rational beliefs based on all available evidence tell us we should be very confident of that conclusion already. They should instead have said something like “even if you naively believe in those methods, for this data the result is different”, but such (appropriate) epistemic modesty is absent.

The paper is quite frustrating in that the authors seem to not recognize which of their statistics are actually most informative and persuasive, let alone take the deeper dive into specific implications that could have been done. The natural experiment interpretation of some of the results is more compelling than the behavioral-association-based analysis (see below). The authors overstate the value of their association statistics and effectively endorse the same flawed methods that are the source of the “vapers are less likely to quit” literature. Continue reading