Impact of PM2.5 Exposure on Cardiovascular diseases (IPEC Study): an updated umbrella review of systematic reviews and meta-analyses

AIMS: 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 meta-analyses (MAs) have limited translational clarity. METHODS AND RESULTS: 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. 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 [relative risk (RR): 1.02, 95% confidence interval (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 cardiovascular mortality. Several reviews identified dose-dependent relationships, with increased risk observed even at PM2.5 concentrations below current WHO standards (5 µg/m3 annual mean; 15 µg/m3 24 h mean), US national air quality standards (12 µg/m3 annual mean; 35 µg/m3 24 h mean), and Indian national air quality standards (40 µg/m3 annual mean; 60 µg/m3 24 h 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. CONCLUSION: This umbrella review consolidates high-level evidence linking PM2.5 exposure to a broad spectrum of adverse cardiovascular outcomes. The findings underline the urgent need to tighten global air quality regulations, prioritize vulnerable populations, and advance mechanistic and regional research to inform tailored policy interventions.