E-cigarette use is linked to a higher risk of heart attack, particularly among former smokers

E-cigarette use is linked to a higher risk of heart attack, particularly among former smokers

A large meta-analysis suggests that vaping is not cardiovascularly neutral because the increased heart attack risk is concentrated in people who have previously smoked, raising questions about e-cigarettes as harm reduction tools.

In a systematic review and meta-analysis recently published in the journalBMC public healthResearchers examined the association between electronic cigarette (e-cigarette) use and the risk of heart attack (MI) and stroke. The study pooled data from 12 observational studies with large population samples to examine whether vaping is linked to cardiovascular outcomes while accounting for conventional cigarette smoking.

Analysis showed that e-cigarette users were 53% more likely to have a myocardial infarction than non-users. Notably, former cigarette smokers who currently use e-cigarettes were more than twice as likely to have a heart attack. These results raise concerns about the cardiovascular safety of e-cigarettes and suggest that they should not be viewed as a risk-free alternative.

Smoking, vaping and cardiovascular disease

For decades, cigarette smoking has been considered a major risk factor for coronary heart disease, high blood pressure 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 in smoking cessation.

These devices atomize nicotine-containing liquids, which typically contain propylene glycol, vegetable glycerin and flavorings. When heated, propylene glycol can form aldehydes and other reactive compounds known to cause cardiovascular disease.

Uncertainty about the safety of e-cigarettes

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

Therefore, a comprehensive analysis that carefully considers 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 an important confounder and subgroup variable.

The 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 with human participants that reported the prevalence or incidence of MI or stroke.

Study selection and statistical methods

Studies with alleged financial ties to the tobacco industry were excluded to minimize bias. Twelve studies met the inclusion criteria and included 430,875 participants for MI analyzes 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 myocardial infarction compared to nonuse (OR 1.53, 95% CI 1.17–1.89). After accounting for cigarette smoking, the association remained statistically significant but weakened (OR 1.24, 95% CI 1.11–1.37).

Former cigarette smokers who currently use e-cigarettes had a 2.52-fold higher risk of MI compared to 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 results were less consistent. Overall, e-cigarette users did not show a statistically significant increase in stroke risk (OR 1.05, 95% CI 0.91-1.19), and smoking-adjusted analyzes were also not significant.

However, the probability of stroke among former smokers who currently use e-cigarettes was significantly higher at 73% than among non-users (OR 1.73, 95% CI 1.30–2.15).

Among e-cigarette-only 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 could be influenced by misclassification of smoking status.

Interpretation, limitations and implications

This systematic review suggests that e-cigarette use is associated with an increased risk of myocardial infarction, particularly among individuals with a history of cigarette smoking. Although exclusive vaping was not associated with a statistically significant cardiovascular risk among nonsmokers in this analysis, the increased 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 significant heterogeneity, publication bias, and residual bias remain important limitations. The authors conclude that further high-quality longitudinal studies are needed and e-cigarettes should not be considered safe from a cardiovascular perspective.

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