A new study shows that in people without a history of smoking, smoking is not associated with an increase in the incidence of heart disease. The study found that previous studies claim that this connection is methodologically flawed.
This paper, published in the American Journal of Preventive Medicine, refutes three earlier studies that broadly link e-cigarettes to a higher risk of heart attack, even among people who have never smoked.
Among people who have never smoked, e-cigarette use is not associated with an increased risk of heart attack. Said Dr. Michael Siegel, professor of community health sciences at Boston University and one of the authors of the new study.
A 2018 study was also published in the American Journal of Preventive Medicine, claiming that daily e-cigarette smoking increases the chance of heart attack. However, it only includes participants who use e-cigarettes and combustible cigarettes at the same time-no participants who use e-cigarettes alone.
Another group of researchers who were skeptical of this approach published a response, arguing that it is important to examine the alleged connection between people who have never smoked combustible cigarettes. The author of the original study posted a reply to this reply, believing that such a distinction is unnecessary.
At the same time, two other papers were published based on the claims of the original paper, which provided further harmful legitimacy for the link between e-cigarettes and heart disease.
The second of these two papers-one of its co-authors, Dr. Stanton Glantz, a well-known opponent of tobacco harm reduction, was once Siegel’s mentor. The article was withdrawn in 2020 because it claimed that e-cigarettes cause heart disease The claim of a disease attack is based on evidence that includes a heart attack before the heart attack.
Obviously, the previous conclusion that using e-cigarettes itself can cause a heart attack is wrong.
The new study, co-authored by Siegel and UC Berkeley business professor Dr. Clayton Critcher, analyzed data from 175,546 respondents in the annual National Health Interview Survey from 2014 to 2019.
They found that daily use of e-cigarettes is only associated with a higher incidence of heart attacks in people who currently smoke combustible cigarettes-and there is no evidence that e-cigarettes who have never smoked combustible cigarettes have an increased risk of heart attack.
In other words, the original study reached conclusions about the perceived cause (e-cigarette) and effect (heart attack) without considering the key variable (smoking).
Seemingly inexplicable, the original 2018 paper omits the 2015 data, and subsequent papers based on it do the same. "When the data is easily available, they ignore the data for that year, which seems strange." Siegel said.
A re-analysis of the data set used in the original study, together with the most recent available data and missing 2015 data, shows that the association between e-cigarette use and heart attack depends on a person’s smoking history.
Correlation is not causation. When researchers fall into such traps, correlation is worrying.
Crichcher and Siegel acknowledged that a more thorough analysis of previous research would reveal that e-cigarettes are relatively new, limiting our ability to assess long-term health effects and compare with combustible tobacco smoking. But it is clear that the conclusions of previous studies that using e-cigarettes can cause heart attacks by themselves are wrong.
Poor research has led to poor policies in the field of tobacco harm reduction, making it harder for smokers to switch to safer options. Correlation is not causation. When highly qualified researchers fall into such traps, it can be worrying-at the expense of accurate public health information. The correlation between e-cigarette use and the incidence of heart attacks cannot be used as evidence that e-cigarette use increases the incidence of heart attacks.
"By analogy, if a person models height as a function of weight, then the output cannot be used to simulate counterfactual scenarios to understand how short a person will be after losing weight," Klitsch and Siegel wrote.