Risk of Cardiovascular Disease Similar in Dual E-Cigarette and Traditional Cigarette Users: Study

Key points of the research:

A study of over 24,000 American adults has found that using both traditional cigarettes and electronic cigarettes does not decrease the risk of cardiovascular disease and may lead to harmful health effects similar to smoking. Those who use both traditional cigarettes and e-cigarettes do not have significantly lower risks of heart attacks, heart failure, or strokes compared to those who only smoke, nor did they report any self-reported cardiovascular disease outcomes. While those who use only e-cigarettes reported fewer cardiovascular events than those who only smoked traditional cigarettes, the number of reported heart events was too small to draw clear conclusions on the effects of solely using e-cigarettes in the study sample. Researchers note the need for more long-term data on e-cigarette use. The study was published on May 6, 2022, in the flagship peer-reviewed journal "Circulation" of the American Heart Association.

Traditional cigarette smoking is widely recognized as a major cause of serious health conditions. According to updated statistics from the American Heart Association on heart disease and stroke in 2022, nearly one-fifth of all deaths in the United States each year are attributed to smoking and exposure to secondhand smoke. Electronic cigarettes, which contain numerous toxic chemicals, are increasingly popular as another way for people to consume nicotine.

According to Dr. Stokes, the lead investigator and senior author of the study, Andrew C. stated, "The risk of cardiovascular disease associated with dual use of traditional combustible cigarettes and electronic cigarettes, similar to smoking, is an important finding because many Americans are using e-cigarettes in an attempt to reduce smoking as they perceive the risk of e-cigarettes to be lower." Dr. Stokes, Assistant Professor in the Department of Global Health at the Boston University School of Public Health, further explained that "People are attempting to transition from traditional cigarettes to e-cigarettes, and dual use of both products is common.

To investigate the relationship between cardiovascular disease, the use of electronic and traditional cigarettes, and their combined use, researchers examined data from the Population Assessment of Tobacco and Health (PATH) study. This nationally representative study collected self-reported health and nicotine product usage information from over 24,000 adults between 2013 and 2019, across five annual waves. After adjusting for age, gender, and race/ethnicity, the study focused on adults, over 50% of whom were under the age of 35, and 51% of whom were female.

Participants who reported smoking during any round of data collection after smoking over 100 combustible cigarettes in their lifetime were classified as smokers. E-cigarette users were identified based on self-reported e-cigarette use during any round of data collection. The groups were classified as follows: 1) current non-users of e-cigarettes or combustible cigarettes (14,832 individuals; this group may include former smokers or former e-cigarette users); 2) e-cigarette use only (822 individuals); 3) combustible cigarette use only (6,515 individuals); or 4) mixed use of combustible cigarettes and e-cigarettes (1,858 individuals).

The analysis defined cardiovascular events as either self-reported diagnoses of a heart attack, coronary artery bypass surgery, heart failure, other heart conditions, or stroke within the past 12 months. The researchers also examined the specific outcomes of self-reported heart attack, heart failure, or stroke. The review identified over 1,480 cases of cardiovascular disease and more than 500 cases of heart attack, heart failure, or stroke.

Analysis of all study participants revealed:

Compared to those who only smoke traditional cigarettes, individuals who smoke both traditional cigarettes and use e-cigarettes do not have a significant difference in the risk of developing cardiovascular diseases such as heart attacks, heart failure, or strokes. Those who only use e-cigarettes or use both traditional and e-cigarettes are younger than those who do not use these products at all: 62% of e-cigarette only users and 54% of dual users are under the age of 35, compared to 51% of non-users. The researchers note that only using e-cigarettes has a reported 30%-40% lower risk of self-reported cardiovascular disease events compared to traditional smoking, although this association is important for any cardiovascular outcome, including congenital heart disease or myocarditis (e-cigarette users reported 41 events, compared to 569 for smokers), rather than specifically for heart attacks, heart failure, or strokes (15 events reported by e-cigarette users, compared to 242 for smokers). Considering the limited amount of self-reported data from e-cigarette users, the researchers conclude that more data is needed in this field.

Even though the PATH study is providing basic longitudinal data on traditional cigarette and e-cigarette use and cardiovascular events, the data is self-reported, the study duration is short, and the event rates are still low - especially among young people. As e-cigarette use is still relatively new, there is currently not a vast amount of long-term evidence to determine the ultimate risks associated with using these products over time. Therefore, we look forward to obtaining more data from this and other ongoing studies. It is important to remember that even with traditional cigarette use, it took decades of use and monitoring to provide us with the evidence we now have to confirm the significant harm of combustible cigarettes," said Rose Marie Robertson, MD, FAHA, American Heart Association deputy chief science and medical officer and co-director of the Tobacco Regulation and Addiction Center, which supports the study.

People should be aware that electronic cigarettes contain addictive nicotine and toxic chemicals that may have adverse effects on their cardiovascular system and overall health.

A key limitation noted by researchers in this study is the low incidence of individual and cardiovascular events in the group of exclusive e-cigarette users. While only 15 individuals who exclusively used e-cigarettes reported diagnoses of heart attack, heart failure, or stroke, the small number of individuals and events makes it difficult to draw definite conclusions about the impact of exclusive e-cigarette use on the study sample.

Stokes has stated that many smokers who attempt to quit using e-cigarettes actually continue to use both products, becoming dual users, and as a result, their cardiovascular risks do not decrease. "We are concerned that any recommendations for using e-cigarettes to quit smoking may lead to an increase in dual use among young people and never smokers, as well as initiation of e-cigarette use.

Electronic cigarettes are not approved by the US Food and Drug Administration (FDA) for smoking cessation. We urge anyone who smokes and is interested in quitting to discuss FDA-approved, effective smoking cessation options with their doctor and healthcare team," said Robertson.

The Tobacco Regulation Science Center of the American Heart Association received funding for this study through grants from the United States government. The Center for Tobacco Products at the Food and Drug Administration obtained the funding through the National Heart, Lung, and Blood Institute at the National Institutes of Health. The American Heart Association is working closely with investigators from institutions across the nation through this Center to conduct research aimed at increasing existing knowledge about the health effects of smoking and nicotine-containing products (including e-cigarettes). These findings can help provide information for public health and tobacco product regulation.

The co-authors of this work are Jonathan B. Bellows, B.A.; Wubin Xie, Dr.P.H., M.P.H.; Alyssa F. Halbower, Dr.P.H., M.P.H.; Naomi M. Hamburg, M.D.; Michael J. Blaha, M.D., M.P.H.; Aruni Bhatnagar, Ph.D., FAHA; and Emelia J. Benjamin, M.D., Sc.M., FAHA.

Source: American Heart Association.