Analysis of mortality related to air pollution exposure: the modifying effect of socioeconomic status (EP-PARTICLES study)

Abstract Introduction Socioeconomic status significantly impacts the prognosis of patients with chronic diseases; however, there are few reports on its association with environmental risk factors. Purpose To assess the short-term exposure to air pollution's effect on mortality, including respiratory disease (RD) and cardiovascular disease (CVD) mortality, we also analyzed the modifying effect of residents' sex, age, and socioeconomic status. Methods The study covered a region of Poland inhabited by 8 million residents from 2011–2020 (80 million person-years of observation). Mortality (all-cause, CVD and RD) data were obtained from the Central Statistical Office, and pollutant concentration estimates were derived using the GEM-AQ model developed for all analyzed municipalities, providing high-quality geographic and temporal resolution. In the first stage, county-specific risk estimates (LAU-2 level) were calculated using a quasi-Poisson regression model, accounting for chronobiology, weather conditions, COVID-19 pandemic, influenza seasons etc. In the second stage, the county-specific results were aggregated using a multilevel random-effects meta-analysis. The study assessed the association between exposure to increased pollutant concentrations (PM2.5 and NO2) by 10 μg/m³ and mortality within 72 hours of exposure. Results A total of 831,246 deaths were recorded, including 377,374 and 45,380 deaths attributed to CVD and RD, respectively. The age at death was higher among CVD cases compared to RD (median 82 vs. 80 years, p<0.001). Men were more likely to die from RD (59.2%), whereas women accounted for the majority of CVD-related deaths (53.8%). Exposure to PM2.5 and NO2 significantly increased the risk of all cause death (by 5.5% and 6.2%, respectively), including CVD (both by 7.7%) and RD (by 9.3% and 9.8%, respectively) [Figures 1 and 2]. Both analyzed sex and age groups were affected by the negative effects of air pollutants in all analyzed outcomes. Residents of areas with low and medium socioeconomic status were more vulnerable to CVD-related deaths associated with PM2.5 exposure (pinteraction=0.026), as well as to all-cause mortality (pinteraction=0.02) and CVD mortality (pinteraction=0.007) associated with NO2 exposure. Conclusion Short-term exposure to air pollution might trigger acute CVD and RD leading to death. Air pollution also significantly increased all-cause mortality. Residents of areas with low and medium socioeconomic status may be more vulnerable to the effects of air pollution. Systemic interventions should prioritize regions with the lowest socioeconomic status.PM2.5 exposure and mortality.NO2 exposure and mortality.