The study titled, “Electronic Cigarette Use and Myocardial Infarction Among Adults in the US Population Assessment of Tobacco and Health,” was published in the Journal of the American Heart Association in June 2019. The cross-sectional study used data from the baseline survey of the Population Assessment of Tobacco and Health (PATH) collected in 2013-2014, to look for a relationship between e-cig use and heart attacks.
The study authors found that people who vaped were more likely to report ever having had a heart attack in the past, and subsequently concluded that e-cig use doubled one’s chances of having a heart attack. Several health experts had spoken up highlighting the flawed premise of such a claim.
Did vaping cause the heart attacks?
Public health expert Dr. Michael Siegel for one, pointed out “that the problem with drawing a causal conclusion from this cross-sectional study, is that there is no way to know which came first: the vaping or the heart attack.” As mentioned with regards to similar studies, Siegel pointed out that it is fairly common for former smokers to switch to vaping after experiencing heart attacks and other health scares.
“If this is the case, then it is not the vaping that is causing the heart attacks; instead, it is really the heart attacks “causing” the vaping. In epidemiology, we call this “reverse causation,” and it is a common limitation of cross-sectional studies, especially when they do not ask about the time course of exposures and outcomes,” he explained.
“Based on what I saw as a likely possibility of reverse causation and on the inability of the study to determine whether the vaping actually preceded the heart attacks, I argued that the investigators went too far in their conclusion and that, in fact, the study does not provide evidence that vaping causes heart attacks,” concluded Siegel.
The study authors failed to provide the required evidence
In line with Siegel’s arguments, after becoming aware that the study did not account for this information, the Journal of the American Heart Association has decided to retract the study. When the reviewers stumbled across this obviously unanswered question during the peer review, they requested that the authors use additional data in the PATH codebook (age of first MI and age of first e‐cigarettes use) to address this concern.
In response to this request, the authors did provide some additional analysis, however the reviewers could not confirm that the authors had both understood and complied with the request prior to acceptance of the article for publication. Post publication, the editors requested the study authors to conduct the analysis based on when the respondents had started using e‐cigarettes, and while the authors agreed to comply they claimed that they could not meet the stipulated deadline as they were unable to access the PATH database.