Key points are not available for this paper at this time.
BACKGROUND: Fine particulate matter (PM2.5) is a well-recognized environmental pollutant increasingly implicated in the pathogenesis of cardiovascular disease (CVD). Whilst numerous studies have established its deleterious effects, incongruencies in the magnitude, dose-response gradients, and modifying factors across systematic reviews (SRs) and MAs (MAs) have limited translational clarity. METHODS: Per the PRISMA guidelines, we conducted an umbrella review of SRs and MAs examining the association between PM2.5 exposure and cardiovascular morbidity, mortality, or intermediate biomarkers in human populations. Searches were performed across PubMed, Scopus, Embase, Web of Science, Cochrane Library, and Google Scholar up to June 2025. The methodological quality of included reviews was appraised using AMSTAR 2 and ROBIS. RESULTS: Thirty-eight SRs and MAs met eligibility criteria, encompassing data from diverse geographic regions and demographic settings. Cumulative evidence demonstrates a robust association between both short- and long-term PM2.5 exposure and elevated cardiovascular risk, including myocardial infarction (RR: 1.02, 95% CI: 1.01-1.03), stroke (RR: 1.011, 95% CI: 1.010-1.012), heart failure (RR: 1.018, 95% CI: 1.011-1.025), arrhythmia (RR: 1.015, 95% CI: 1.006-1.024), and other cardiovascular mortality. Several reviews identified dose-dependent relationships, with increased risk observable even at PM2.5 concentrations below current WHO standards (5 µg/m³ annual mean; 15 µg/m³ 24-hour mean), U.S. national air quality standards (12 µg/m³ annual mean; 35 µg/m³ 24-hour mean), and Indian national air quality standards (40 µg/m³ annual mean; 60 µg/m³ 24-hour mean) have also been associated with increased cardiovascular risk. Subgroup analyses highlighted increased susceptibility among older adults, individuals with pre-existing CVD, and populations in low- and middle-income countries. Whilst most reviews were rated as moderate-to-high quality, methodological heterogeneity in exposure assessment and under-representation of data from South Asia and sub-Saharan Africa remain key limitations. CONCLUSIONS: This umbrella review consolidates high-level evidence linking PM2.5 exposure to a broad spectrum of adverse cardiovascular outcomes. The findings underscore the urgent need to tighten global air quality regulations, prioritize vulnerable populations, and advance mechanistic and regional research to inform tailored policy interventions.
Sethi et al. (Sun,) studied this question.