New analysis clarified the link between "exclusive" use of e-cigarettes and COPD

A Johns Hopkins Medicine-led analysis of medical information gathered on a diverse group of almost 250,000 people over four years has significantly clarified the link between the "exclusive" use of e-cigarettes and chronic obstructive pulmonary disease (COPD), as well as high blood pressure in a sub-group of adults 30 to 70 years of age.

The findings, supported by funding from the National Institutes of Health and published in the March. 15 edition of Nicotine & Tobacco Research, underscore the potential risks of e-cigarette use, and should provide context to inform advice and regulatory policies about the health risks of so-called vaping products.

The new analysis, they note, further verifies that while the use of either e-cigarettes or traditional "combustible" cigarettes is linked to higher risks and rates of chronic obstructive pulmonary disease (COPD), the effect is substantially stronger for traditional cigarettes.

In the U.S., e-cigarettes have become the second-most prevalent form of tobacco use after cigarettes, and the most common among young adults and adolescents. According to the Centers for Disease Control and Prevention (CDC), e-cigarettes have risen in use among young adults from 3.7% in 2020 to 4.5% in 2021.

In 2021, about 3 in 10 (29.4%) adults who vaped also smoked cigarettes. While e-cigarettes are often marketed as being safe, some studies have indicated that e-cigarette aerosols may contain significant levels of dangerous organic compounds and higher levels of nicotine, which can be addictive and harmful.

Studies over many decades have shown that combustible cigarettes consistently increase the risk of cardiometabolic diseases such as heart disease, heart attack, heart failure, and stroke. According to the CDC, combustible cigarette users account for 8 out of 10 COPD-related deaths in the US.

A previous cross-sectional study - a study in which researchers collect data from many individuals at a single point in time - found increased risk of asthma in people using e-cigarettes, while a longitudinal study - a study in which researchers repeatedly observe the same individuals or groups over a long period of time - indicated a higher risk of new respiratory disease symptoms.

As a result, "there remains great uncertainty about the relative harm of e-cigarettes as compared to traditional smoking. Until now, there has been scant longitudinal data in large high-quality datasets linking exclusive e-cigarettes use to new-onset cardiometabolic health conditions," says Michael Blaha, M.D., M.P.H., senior author of the study and professor of cardiology and epidemiology at the Johns Hopkins University School of Medicine.

For the analysis, researchers used medical information on 249,190 people, including 203,932 who reported never using e-cigarettes or combustible cigarettes (203,932), 3,164 who reported exclusively using e-cigarettes, 33,778 who reported exclusively using combustible cigarettes, and 8,316 who reported using both e-cigarettes and combustible cigarettes.

Those who experienced disease were characterized by their e-cigarette and combustible cigarette use patterns. In the follow-up period after almost four years, 23,745 new cases of hypertension were found, along with 13,179 new cases of type 2 diabetes; 7,925 new cases of COPD; 9,801 new cases of heart failure; and 6,139 new cases of atherosclerotic cardiovascular disease. Of those cases, it was found that exclusive e-cigarette use was not significantly associated with type 2 diabetes, heart failure or atherosclerotic cardiovascular disease, but it was significantly associated with COPD. In a sub-analysis of individuals ages 30–70, there was a small increased risk of hypertension.

In contrast, results showed that exclusive use of combustible cigarettes significantly increased the risks for all outcomes, including hypertension, type 2 diabetes, COPD, heart failure, and atherosclerotic cardiovascular disease. Similar results were shown for dual use of combustible cigarettes and e-cigarettes although risk estimates were slightly larger than for exclusive combustible cigarette use.

These results are a critical stepping stone for future prospective research on the health effects of e-cigarettes. While in this short-term study there was no association between exclusive e-cigarette use and cardiovascular events, there was an association with incident COPD and possibly hypertension that will need to be closely watched over longer term follow-up."

Michael Blaha, M.D., M.P.H., senior author of the study and professor of cardiology and epidemiology, Johns Hopkins University School of Medicine

Blaha says the new study suggests that e-cigarettes have definite potential health risks, although the risks may be less than what is seen for traditional combustible cigarette smoking alone.

This study received partial support from grants provided by the National Heart, Lung, and Blood Institute of the National Institutes of Health and the Center for Tobacco Products at the Food and Drug Administration [HL120163].