A new systematic review and meta-analysis published in BMC Public Health links e-cigarette use to an increased risk of heart attack, particularly among former smokers. The study combined data from 12 observational studies with large population samples to evaluate whether vaping affects cardiovascular health, while accounting for traditional cigarette use.
The analysis found that e-cigarette users had 53% higher odds of experiencing a heart attack compared with non-users. Among former smokers who now vape, the odds more than doubled. These results challenge the assumption that e-cigarettes are a safe alternative to smoking.
Smoking, Vaping, and Heart Health
Cigarette smoking has long been recognized as a major risk factor for coronary artery disease, hypertension, and stroke. In response, the tobacco industry introduced electronic nicotine delivery systems, commonly known as e-cigarettes or vapes, promoting them as harm-reduction tools for smokers.
E-cigarettes heat nicotine-containing liquids, often with propylene glycol, vegetable glycerin, and flavorings. Heating propylene glycol can produce reactive compounds that contribute to cardiovascular disease.
Safety of E-Cigarettes Remains Unclear
Despite growing global use, the cardiovascular safety of e-cigarettes is debated. Some studies suggest lower risk for exclusive vapers, but many have limitations such as cross-sectional design, residual confounding from smoking history, or potential industry bias. A comprehensive analysis accounting for cigarette use is needed to clarify the independent risks of vaping.
Study Design and Methods
The researchers conducted a systematic review and meta-analysis following 2020 PRISMA guidelines. They included observational studies and randomized trials reporting myocardial infarction (MI) or stroke outcomes and excluded studies with tobacco industry funding.
Twelve studies met the criteria, including 430,875 participants for MI analyses and over 1.1 million for stroke. Random-effects models estimated odds ratios (ORs) and 95% confidence intervals (CIs) for cardiovascular outcomes.
Key Findings
Myocardial Infarction: E-cigarette users had 53% higher odds of MI compared with non-users (OR 1.53, 95% CI 1.17–1.89). After adjusting for cigarette smoking, the odds remained elevated (OR 1.24, 95% CI 1.11–1.37). Former smokers who vape had a 2.5-fold higher odds of MI (OR 2.52, 95% CI 1.88–3.16).
Stroke: Overall, e-cigarette use was not significantly associated with stroke (OR 1.05, 95% CI 0.91–1.19). Among former smokers who vape, stroke risk was 73% higher (OR 1.73, 95% CI 1.30–2.15). Exclusive e-cigarette users who never smoked had no significant increase in MI (OR 0.96) or stroke (OR 0.97), though data were limited.
Implications and Limitations
The findings suggest e-cigarettes increase heart attack risk in people with a history of smoking, raising questions about their role as harm-reduction tools. Most studies were cross-sectional, which limits causal conclusions. Heterogeneity, publication bias, and residual confounding remain concerns.
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