PM_2.5 Composition Exposure and Cardiovascular Disease: A Multicohort Study Integrating Disease Incidence and Biomarkers

The chemical composition of PM_2.5 differentially influences cardiovascular risk, but evidence integrating clinical and subclinical end points is limited. Here, we evaluated the long-term exposure to seven PM_2.5 components in 255,394 All of Us participants (2017–2022) for incident myocardial infarction (MI) and stroke, and in 648 COMPASS participants (2015–2019) for troponin, TNF-α, and MCP-1. Our findings revealed that organic matter (OM), sulfate (SO42–), and sea-salt (SS) showed consistent associations. For instance, per interquartile-range OM: hazard ratios of 1.33 (95% CI, 1.07–1.67) for MI and 1.40 (95% CI, 1.08–1.81) for stroke; odds ratio of 1.40 (95% CI, 1.01–1.94) for troponin elevation and 1.40 (95% CI, 1.03–1.90) for TNF-α elevation; linear coefficient of 0.40 (95% CI, 0.18–0.61) for MCP-1. In mixture analysis, OM, SO₄^2–, and SS each contributed ≥ 19% of the overall association for all outcomes. We found that long-term exposure to specific PM_2.5 components, particularly OM, SO₄^2–, and SS, is associated with increased cardiovascular risk and subclinical dysfunction, underscoring the need for component-based air quality regulation.