The Associations Between Secondhand Smoke Exposure and Various Cardiovascular Diseases: A Meta-Analysis

INTRODUCTION: Despite various meta-analyses conducted to explore the association between SHS and CVD, gaps and mixed results remained in the literature. This study aims to examine the associations between SHS and individual CVDs with moderation analyses of sexes, countries/regions, and exposure types. METHODS: Publications in four databases (PubMed, CINAHL ultimate, Embase, and Web of Science) from inception to May 2, 2024, were included. Cochrane ROBINS-E was used for bias evaluation. The robust variance estimation model was used for meta-analyses. Subgroup analyses were conducted to compare the differences in sex, geographic regions, and exposure type. Odds ratios, 95% confidence intervals, and p-values were reported to assess effect sizes and statistical significance. Cochran's Q test with the I2 statistic was used to test heterogeneity. Egger's test and funnel plots were used for publication bias. RESULTS: 57 studies were included. SHS exposure increases the odds of hypertension (OR: 1.28, 95% CI: 1.15 to 1.40), heart disease (OR: 1.39, 95% CI: 1.28 to 1.50), myocardial infarction (OR: 1.50, 95% CI: 1.17 to 1.84), stroke (OR: 1.36, 95% CI: 1.18 to 1.54), and nonspecific CVDs (OR: 1.50, 95% CI: 1.26 to 1.74). Compared to other countries, the U.S. has lower odds ratios (ORs), and European countries have higher ORs in various CVDs. Home exposure has a higher risk of CVD than non-home exposure. No sex differences were found. CONCLUSION: Public education to raise awareness of the health impacts of SHS exposure on a population level, legislation and execution of public smoking bans on the government level and efforts toward smoke-free homes at family levels are recommended.