E-cigarette use is linked to higher heart attack risk, especially in former smokers

By Hugo Francisco de SouzaReviewed by Susha Cheriyedath, M.Sc.Dec 14 2025

A large meta-analysis suggests that vaping is not cardiovascularly neutral, with elevated heart attack risk concentrated among people who previously smoked, raising questions about e-cigarettes as harm-reduction tools.

Study: Are electronic cigarettes associated with the risk of myocardial infarction and stroke? A systematic review and meta-analysis. Image Credit: magnet studio / Shutterstock

In a recent systematic review and meta-analysis published in the journal BMC Public Health, researchers investigated the association between electronic cigarette (e-cigarette) use and the risk of myocardial infarction (MI) and stroke. The study pooled data from 12 observational studies involving large population samples to examine whether vaping is linked to cardiovascular outcomes while accounting for conventional cigarette smoking.

Analyses showed that e-cigarette users had 53% higher odds of MI compared with non-users. Notably, among former cigarette smokers who currently use e-cigarettes, the odds of a heart attack were more than doubled. These findings raise concerns about the cardiovascular safety of e-cigarettes and indicate that they should not be assumed to be risk-free alternatives.

Smoking, Vaping, and Cardiovascular Disease

For decades, cigarette smoking has been recognized as a major risk factor for coronary artery disease, hypertension, and stroke. In response, the tobacco industry introduced electronic nicotine delivery systems (ENDS), commonly referred to as e-cigarettes or “vapes,” and promoted them as harm-reduction tools to aid smoking cessation.

These devices aerosolize nicotine-containing liquids that typically include propylene glycol, vegetable glycerin, and flavoring agents. When heated, propylene glycol can generate aldehydes and other reactive compounds that are known contributors to cardiovascular disease.

Uncertainty Around E-Cigarette Safety

Despite rapid global uptake, the cardiovascular safety of e-cigarettes remains controversial. Human studies have produced conflicting results, with some suggesting lower risk for exclusive vapers, while others were limited by cross-sectional designs, residual confounding by smoking history, or potential industry-related conflicts of interest.

As a result, a comprehensive analysis that carefully accounts for conventional cigarette smoking is needed to clarify the independent cardiovascular risks associated with vaping.

Systematic Review Design and Data Sources

The present study addressed this gap using a systematic review and meta-analysis (SRMA) conducted in accordance with the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Conventional cigarette smoking was treated as a key confounder and subgroup variable.

Researchers searched PubMed, Cochrane Library, and Web of Science for studies published between January 2005 and June 2025. Eligible studies included observational designs and randomized trials involving human participants that reported the prevalence or incidence of MI or stroke.

Study Selection and Statistical Methods

Studies with reported financial ties to the tobacco industry were excluded to minimize bias. Twelve studies met the inclusion criteria, comprising 430,875 participants for MI analyses and more than 1.1 million participants for stroke analyses.

Random-effects models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) to quantify associations between e-cigarette use and cardiovascular outcomes.

Myocardial Infarction and Stroke Findings

Overall, e-cigarette use was associated with a 53% higher odds of MI compared with non-use (OR 1.53, 95% CI 1.17–1.89). After adjustment for cigarette smoking, the association remained statistically significant but attenuated (OR 1.24, 95% CI 1.11–1.37).

Former cigarette smokers who currently use e-cigarettes had a 2.52-fold higher odds of MI compared with non-users (OR 2.52, 95% CI 1.88–3.16). The authors note that this may reflect residual confounding or cumulative effects of prior smoking rather than a direct causal effect of vaping alone.

Stroke outcomes were less consistent. Overall, e-cigarette users showed no statistically significant increase in stroke risk (OR 1.05, 95% CI 0.91–1.19), and smoking-adjusted analyses were similarly non-significant.

However, among former smokers who currently use e-cigarettes, stroke odds were significantly higher at 73% above non-users (OR 1.73, 95% CI 1.30–2.15).

Among exclusive e-cigarette users who had never smoked combustible cigarettes, no significant association was observed for MI (OR 0.96) or stroke (OR 0.97). These estimates were based on limited data and may be affected by misclassification of smoking status.

Interpretation, Limitations, and Implications

This systematic review suggests that e-cigarette use is associated with increased odds of myocardial infarction, particularly among individuals with a history of cigarette smoking. Although exclusive vaping among never-smokers was not associated with statistically significant cardiovascular risk in this analysis, the elevated risk observed among former smokers raises concerns about the use of e-cigarettes as harm-reduction or transition tools.

Most included studies were cross-sectional, limiting causal inference, and substantial heterogeneity, publication bias, and residual confounding remain important limitations. The authors conclude that further high-quality longitudinal studies are required and that e-cigarettes should not be considered harmless from a cardiovascular perspective.