E‐cigarettes are presented as an alternative to combustible cigarettes, but a study shows that these products are associated with higher risk of myocardial infarction.


 

Published research has shown that risks of myocardial infarction (MI) are significantly higher among young smokers when compared with those who have never smoked. E-cigarettes have been promoted as a less dangerous way to self‐administer nicotine than conventional cigarettes, and studies suggest people with heart disease are using e‐cigarettes as a smoking cessation aid. “E-cigarettes are promoted as a safe alternative to combustible cigarettes even though they deliver an aerosol of ultrafine particles, acrolein, nicotine, and other elements that are toxic to the cardiovascular system,” says Stanton A. Glantz, PhD.  “In fact, they have negative effects on the cardiovascular system, often occurring within minutes.”

Few epidemiological studies have evaluated clinical outcomes for those who use e‐cigarettes, representing a significant research need. Recently, studies using data from the National Health Interview Survey and the Behavioral Risk Factors Surveillance Survey found cross‐sectional associations between e‐cigarette use and having had an MI among daily e‐cigarette users, even after controlling for combustible cigarette smoking and other risk factors.

 

Further Analyzing the Relationship 

For a study published in the Journal of the American Heart Association, Dr. Glantz and colleagues used the Population Assessment of Tobacco and Health (PATH) data set to assess the association between e‐cigarette use and having had an MI. PATH is a nationally representative population‐based cohort study that collects data on use of tobacco products, health outcomes, risk perception, and attitudes. “We used these data to assess the risks that e-cigarette smoking confers to MI at the population level,” Dr. Glantz says.

According to the results, every day and some day e‐cigarette smoking was independently associated with a higher likelihood of having had an MI, and a significant dose‐response relationship was observed (Table). “In practical terms, this means that in patients who use e-cigarettes and continue to smoke—so-called dual use—the risk is higher than just continuing to smoke,” explains Dr. Glantz. “Never smokers using e-cigarettes daily are at increased odds of having had an MI by a factor of 2.25. Daily smoking alone increases the odds by a factor of 2.95. Being a dual user, which is the most common way these products are used, increases the odds ratio by a factor of 6.64 compared with a never smoker of combustible cigarettes who also never used e‐cigarettes.”

There were two key findings of the analysis to emphasize, according to Dr. Glantz. “First, the MI risks associated with e-cigarettes are substantial and approach those of smoking combustible cigarettes,” he says. “Second, the risks of e-cigarettes and combustible cigarettes are independent of each other. This means dual use of these products is doing more damage than simply continuing to smoke combustible cigarettes. This finding is especially important considering that most e-cigarette users are dual users with combustible cigarettes.”

 

Identifying Important Implications

The study confirms findings from previous research that e‐cigarette use is an independent risk factor for having had an MI after controlling for combustible cigarette smoking and demographic and clinical risk factors. Importantly, dual use of e‐cigarettes and combustible cigarettes resulted in higher risks of MI than using either product alone and switching from combustible cigarettes to e‐cigarettes did not yield any benefits in terms of reduced MI risk.

“Our findings demonstrate that physicians should not be recommending e-cigarettes to their patients,” says Dr. Glantz. “They should not be promoted or prescribed as a less risky alternative to regular cigarettes. Physicians need to collaborate with patients who use e-cigarettes to stop smoking, just as they would with conventional cigarettes. As we learn about e-cigarettes, it’s clear we’re seeing that these products are more dangerous than what was previously believed.”

References

Glantz SA, Bhatta DN. Electronic cigarette use and myocardial infarction among adults in the US population assessment of tobacco and health. Dharma N. J Am Heart Assoc. 2019;8:e012317. Available at: https://www.ahajournals.org/doi/10.1161/JAHA.119.012317.

Alzahrani T, Pena I, Temesgen N, Glantz SA. Association between electronic cigarette use and myocardial infarction. Am J Prev Med. 2018;55:455-461.

Gaalema DE, Pericot‐Valverde I, Bunn JY, et al. Tobacco use in cardiac patients: perceptions, use, and changes after a recent myocardial infarction among US adults in the PATH study (2013–2015). Prev Med. 2018;117:76-82.