By Guy Bentley – A Swiss study claiming vaping can lead to smoking and harms current smokers’ chance of quitting suffers from “fatal” flaws, and the paper’s conclusions are misrepresentative, according to a leading public health expert.

“We found no beneficial effects of vaping at follow-up for either smoking cessation or smoking reduction,” the authors conclude in the study.

But Dr. Michael Siegel, a professor in the Department of Community Health Sciences, Boston University School of Public Health, has written a damning critique of the study, which was published in Swiss Medical Weekly.

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“The study fails to establish the baseline vaping status of each participant,” Siegel wrote. “To qualify as a true longitudinal design, the study would identify vapers and non-vapers at baseline and then follow both groups over time to compare changes in smoking status over the follow-up period.”

“Instead, the study measures – at follow-up – whether the participants had used an electronic cigarette any time in the past year,” he continued. “They could have used an e-cigarette for the first time the previous day, for example, and would still be considered as vapers in the analysis.” (RELATED: CDC Data Blows Away Popular E-Cigarette Criticism)

Siegel points out that the researchers don’t compare the changes in smoking behavior over time between vapers and non-vapers. The study only measures changes in smoking over the past year and whether the subjects had ever used an e-cigarette. So, in Siegel’s words, the “study methods do not allow the investigators to determine which came first.”

“Because it is a cross-sectional study, it is impossible to know whether the change in smoking status preceded the use of electronic cigarettes or whether the use of electronic cigarettes preceded the smoking status change,” he wrote.

This omission is critical, as it casts severe doubt over the claim that e-cigarettes are a cause of smoking initiation or failure to quit. The second fatal flaw is that the question used to assess vaping behavior only asked about ever use of e-cigarettes,” Siegel wrote. “It does not assess the frequency of use or its duration. According to the methodology, participants were merely asked whether they had ‘used’ e-cigarettes at any point in the past 12 months.”

But the term “used” was not clarified. Vapers, as defined in the study, included anyone who so much as tried one e-cigarette. “It is entirely possible that many of the participants who the study called vapers were actually not vapers at all, but merely people who had tried an e-cigarette,” Siegel added. (RELATED: CDC Admits, No ‘Concrete’ Evidence E-Cigarettes Are Gateway To Smoking

Siegel’s criticism comes soon after a meta-study arguing that e-cigarettes made it harder for people quit smoking received widespread criticism from health professionals, and was branded an “unscientific hatchet Job.”

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