The role of long-term fine particulate matter peaks in cardiovascular risk: an AIRCARD substudy

Cardiovascular disease is a leading cause of mortality globally, with air pollution, particularly fine particulate matter (PM_2.5), recognized as a significant risk factor. While long-term accumulated exposure to PM_2.5 has been extensively studied, the impact of PM_2.5 peaks on cardiovascular events remains unexplored.

This prospective cohort study analyzed data from 26,723 male participants aged 65 to 74 years from the Danish DANCAVAS and VIVA screening trials. We assessed the association between long-term cumulated repeated PM_2.5 peak exposure and major adverse cardiovascular events (MACE), including non-fatal acute myocardial infarction, non-fatal stroke, cardiovascular mortality, and revascularization procedures, using Cox proportional hazards models. PM_2.5 peak exposure was treated as a time-varying variable, and models were adjusted for potential confounders, including individual-level demographic, clinical, and socioeconomic factors. PM_2.5 peaks were defined as monthly average concentrations exceeding the long-term mean by more than two standard deviations.

The fully adjusted model showed no significant elevation in the risk of MACE associated with increased PM_2.5 peak exposure (HR = 0.9991, 95 % CI: 0.9974-1.0008). This lack of association was consistent across sensitivity analyses and different peak definitions, including shorter-term peaks in the five and one years preceding an event.

Our findings suggest that PM_2.5 peak exposure does not significantly increase the risk of MACE in this Danish population. These results challenge the hypothesis that PM_2.5 peaks over a long period are a determinant of cardiovascular risk. Further research is warranted to explore these relationships in different populations and to investigate potential mechanisms underlying the effects of air pollution peaks on cardiovascular health.