Association between first ischemic major acute cardiovascular events and long-term outdoor air pollution exposure in men: exploring the interaction with cardiovascular health profiles

Modifiable cardiovascular health profiles might modulate the detrimental effects of long-term air pollution exposure on cardiovascular risk, but effect modification is so-far under investigated. We derived the American Heart Association Life’s Simple 7 (LS7)-behavior and LS7-factor scores in a population-based cohort of 2119 men, 50–75 years old and disease-free residents in the Varese city (Northern Italy) at baseline (2013–2016). Exposures were the average concentrations of PM2.5, NO2 and O3 in the 12 months before baseline (EXPANSE project models). From healthcare records, we identified first ischemic Major Acute Cardiovascular Event (iMACE) before 31/12/2022, fatal or non-fatal. We assessed the interaction between each LS7 score and pollutants on relative and absolute scales using Cox and Poisson models, respectively, adjusting for age, education, area-based deprivation, and contextual environmental factors. In 7.6 years of median follow-up, we observed n = 160 events (rate = 10.4 per 1,000 person-years). Mean ± SD PM2.5 were 18.6 ± 1.8 µg/m3; men with poor LS7-behavior were the most exposed. The HR for 1.93 µg/m3-increase in PM2.5 was 1.24 (95%CI:1.02–1.50), and 1.45 (95%CI:1.07–1.97) in men with poor LS7-behavior (interaction test p-value = 0.001); we estimated 7.7 (95%CI:2.8–12.5) additional events per 1,000 person-years due to the interaction. Physical activity and adherence to Mediterranean diet mitigated the effect of PM2.5. Conversely, we observed no interaction between LS7-factor and PM2.5. NO2 showed similar interaction paths. The promotion of healthy behaviors in urban settings may contribute to reduce the harmful effect of pollutants on the cardiovascular system during the transition period to the achievement of EU air quality limits.