In 2019, The Journal of the American Heart Association published a study suggesting that nicotine vaping doubles the risk of a heart attack. The authors claimed e-cigarette use is "independently" associated with a heightened risk of myocardial infarction, which is "similar" to the risk among cigarette smokers.
Three years later, the World Journal of Oncology published a study that claimed vapers face about the same cancer risk as smokers. The authors said "prospective studies should be planned to mitigate the risk."
Both studies were later retracted, largely because they shared the same glaring weakness: The researchers failed to consider whether the medical problems that survey respondents reported were diagnosed before or after they began vaping, a minimum requirement for inferring a causal relationship. As University of Louisville researchers Brad Rodu and Nantaporn Plurphanswat showed in a 2022 Internal and Emergency Medicine article, that failure is characteristic of studies that allege a link between vaping and smoking-related diseases, including several articles that so far have not been retracted.
In all of these cases, the researchers seemed so eager to discredit vaping as a harm-reducing alternative to smoking that they overlooked a fundamental methodological flaw. So did the peer reviewers and journal editors.
This sort of tendentiously sloppy research compounds a problem that harm reduction advocates have been decrying for years: Although the evidence indicates that vaping is far less dangerous than smoking, most Americans think vaping is just as dangerous, if not more so. And while public health officials could help correct that misconception, which undermines the lifesaving potential of e-cigarettes, they frequently contribute to the confusion by obscuring the difference between these two modes of nicotine consumption.
The heart attack study was based on data from the Population Assessment of Tobacco and Health (PATH) Study, which includes questions about when respondents began vaping and when they were diagnosed. Amazingly, the researchers did not use that information, even though it was crucial in testing the hypothesis that vaping causes heart attacks.
Even more remarkably, the journal's editors recognized that problem before publication and asked the authors to address it. Although they failed to do so, the Journal of the American Heart Association published the study anyway.
A month after publication, Rodu and Plurphanswat pointed out that most of the e-cigarette users who reported heart attacks actually had them before they started vaping, making a causal inference logically impossible. Sixteen prominent tobacco researchers amplified that point in a letter to the American Heart Association, which finally retracted the study eight months after it was published.
In their Internal and Emergency Medicine article, Rodu and Plurphanswat analyzed PATH data on four conditions "strongly associated with smoking" that previous research had suggested are also associated with vaping: myocardial infarction, stroke, emphysema, and chronic obstructive pulmonary disease. They again found that the diagnoses generally preceded e-cigarette use.
The World Journal of Oncology study, which was based on the National Health and Nutrition Examination Survey, included information about the timing of cancer diagnoses but not the timing of e-cigarette use. As the authors conceded, that meant "causal or temporal association could not be established."
The editors and peer reviewers apparently were unfazed by that difficulty. They also missed writing errors, non sequiturs, failures of reasoning, contradictions, and a blatant inconsistency in the way researchers reported their main results. Perhaps reviewers were reassured by the fact that the article was attributed to no fewer than 13 authors affiliated with reputable institutions such as the University of Illinois, Temple University Hospital, the Mayo Clinic, and the Icahn School of Medicine at Mount Sinai.
In addition to glossing over the timing of e-cigarette use, the researchers classified participants as "e-cigarette users" if they had ever vaped and were not current smokers. The study did not take into account whether the respondents in that group had a history of smoking, which is problematic when you are trying to distinguish between correlation and causation.
Even while implying that vaping poses about the same cancer risk as smoking, the study cited evidence showing that can't possibly be true. The authors noted that the carcinogenic potency of e-cigarette aerosol is more than 99 percent lower than the carcinogenic potency of cigarette smoke. They added that "mean lifetime cancer risks decline from traditional smoking to e-cigarettes."
The researchers said the "exponential increase in the use of e-cigarettes due to their widespread promotion as safer alternatives to traditional smoking" is a "dangerous threat" and a "public health risk." But they also described e-cigarettes as a promising harm reduction tool that "could dramatically decrease the risk of serious disease in nicotine users and other high-risk groups."
Ten months after publication, the journal printed a retraction notice. "Concerns have been raised regarding the article's methodology, source data processing including statistical analysis, and reliability of conclusions," the editors said. But "the authors failed to provide justified explanations and evidence" in response to those concerns.
Publication of such a "grossly flawed" study, Rodu notes, raises an obvious question: "How could it get through peer review?" Respiratory specialist Riccardo Polosa and smoking researcher Konstantinos Farsalinos suggest an answer in a commentary that accompanied Rodu and Plurphanswat's Internal and Emergency Medicine article.
Polosa and Farsalinos note that the failure to consider the temporal relationship between vaping and disease is a "fatal" flaw that should be obvious to reviewers. "The unopposed acceptance of these (low-quality) papers by prestigious journals is symptomatic of a significant dysfunction in scientific publishing, which is distorting the practice of science," they write. "In the context of highly polarized scientific debates (as in e-cigarette research) the peer review process becomes strongly biased for or against a certain narrative."
In this case, the favored narrative says vaping products should be viewed with suspicion, despite their potential to reduce smoking-related disease and death. Statements from the Centers for Disease Control and Prevention (CDC) reinforce that narrative by inaccurately describing vaping as "tobacco use" and portraying it as a grave threat to public health.
The result of such obfuscation is apparent in opinion surveys. According to a 2020 survey, less than 3 percent of Americans recognize that e-cigarettes are "much less harmful than combustible cigarettes."
Brian King, director of the Center for Tobacco Products at the Food and Drug Administration (FDA), acknowledges the gap between what the evidence shows and what Americans commonly think. "I'm fully aware of the misperceptions that are out there and aren't consistent with the known science," he told the Associated Press in September 2022. "We do know that e-cigarettes, as a general class, have markedly less risk than a combustible cigarette product."
King did not acknowledge the role that his own agency, which sponsors hyperbolic propaganda aimed at deterring adolescent vaping, has played in creating those "misperceptions." Nor did he reflect on the damage done by discouraging smokers from switching to vaping. The upshot will be more tobacco-related deaths, exactly the opposite of what the CDC and the FDA claim they are trying to accomplish.