A recent systematic review and meta-analysis published in BMC Public Health evaluated the relationship between electronic cigarette use and the risk of myocardial infarction (MI) and stroke. By synthesizing data from 12 observational studies with large population samples, the researchers assessed whether vaping is independently associated with cardiovascular outcomes after accounting for conventional cigarette smoking.
The pooled analysis indicated that individuals who use e-cigarettes had 53% greater odds of experiencing an MI compared with non-users. The association was particularly pronounced among former cigarette smokers who currently vape, in whom the odds of heart attack were more than twice as high. These results challenge the perception of e-cigarettes as a safe alternative to combustible tobacco.
Smoking, Vaping, and Cardiovascular Risk
Cigarette smoking has long been established as a major contributor to cardiovascular disease, including coronary artery disease, hypertension, and stroke. In recent years, electronic nicotine delivery systems (ENDS), commonly known as e-cigarettes, have been marketed as harm-reduction tools and smoking cessation aids.
E-cigarettes function by heating nicotine-containing liquids composed primarily of propylene glycol, vegetable glycerin, and flavoring compounds. Thermal degradation of these substances can produce aldehydes and other toxic byproducts implicated in cardiovascular injury.
Evidence Gaps and Rationale for Review
Despite widespread use, the cardiovascular safety of e-cigarettes remains uncertain. Prior human studies have yielded mixed findings, often limited by cross-sectional designs, incomplete adjustment for smoking history, or potential conflicts of interest. Consequently, a comprehensive synthesis that rigorously controls for cigarette smoking was needed.
Methods and Study Selection
The authors conducted a systematic review and meta-analysis following PRISMA 2020 guidelines. Searches of PubMed, the Cochrane Library, and Web of Science covered studies published between January 2005 and June 2025. Eligible studies included observational research and randomized trials reporting MI or stroke outcomes in relation to e-cigarette use.
Studies with financial links to the tobacco industry were excluded. Ultimately, 12 studies met inclusion criteria, encompassing over 430,000 participants in MI analyses and more than one million participants in stroke analyses. Random-effects models were used to calculate pooled odds ratios and 95% confidence intervals.
Key Findings
E-cigarette use was associated with a significantly increased odds of MI (OR 1.53), which remained significant after adjustment for cigarette smoking (OR 1.24). Among former smokers who currently used e-cigarettes, MI odds were markedly higher (OR 2.52).
Stroke findings were less consistent overall, with no significant association observed for e-cigarette use in the full sample. However, former smokers who vaped exhibited a significantly elevated risk of stroke (OR 1.73). No significant associations were detected among never-smokers who exclusively used e-cigarettes, although data in this subgroup were limited.
Conclusions and Implications
The findings suggest that e-cigarette use is linked to increased myocardial infarction risk, particularly among individuals with a history of smoking. While exclusive vaping among never-smokers did not show significant cardiovascular risk, the elevated risks among former smokers raise concerns regarding the role of e-cigarettes in harm-reduction strategies. The authors emphasize the need for longitudinal studies and caution against viewing e-cigarettes as cardiovascularly benign.
