Air pollution, coronary artery disease, and cardiovascular events: Insights from the PROMISE trial

Background

Air pollution is associated with mortality and major adverse cardiovascular events (MACE) in the general population. However, little is known about the relationship between air pollution and coronary artery disease (CAD) and how this relates to MACE.

Methods

This study utilized data from the computed tomography (CT) arm of the PROMISE trial investigating symptomatic individuals with suspected CAD. We linked levels of air pollutants (PM_2·5, PM₁₀, NO₂, and ozone) at U.S. zip codes of residence CT-derived CAD and adjudicated MACE (all-cause death, myocardial infarction, and hospitalization for unstable angina). Multivariable analyses were adjusted for the ASCVD risk score and socioeconomic determinants of health. Mediation analyses were used to test putative pathways.

Results

In 4343 individuals (48 ​% males; age: 61 ​± ​8 years), elevated exposures to PM_2.5 (≥9.4 ​μg/m³) and NO₂ (≥5.3 ​ppb) were independently associated with obstructive CAD (aOR ​= ​1.23, 95%CI: 1.03–1.48, p ​= ​0.024; aOR ​= ​1.56, 95%CI: 1.02–2.40, p ​= ​0.042), while there were no significant associations with PM₁₀ (≥15 ​μg/m³) or ozone (≥51 ​ppb). Increased PM_2.5, PM₁₀ and ozone were independently associated with MACE (aHR ​= ​1.56, 95%CI: 1.12–2.18, p ​= ​0.008; aHR ​= ​2.09, 95%CI: 1.18–3.70, p ​= ​0.011, aHR ​= ​1.96, 95%CI: 1.20–3.21, p ​= ​0.008). In the mediation analysis, obstructive CAD accounted for 9 ​% of the total effect (p ​= ​0.012) between PM_2.5 and MACE.

Conclusion

Exposure to air pollution, particularly PM_2.5, was independently associated with obstructive CAD and MACE, with obstructive CAD mediating a small but significant portion of the association between air pollution and MACE.