Impact of ozone exposure on morbidity and cardiovascular hospitalizations: a population-level analysis in Poland (EP-PARTICLES Study)

Abstract Background Despite extensive research on air pollution, few studies have specifically focused on the health impacts of ozone (O3), a secondary pollutant formed by photochemical reactions. This study is the first large-scale analysis dedicated to examining the direct effects of ozone and its precursors on health outcomes, providing unique insights into this underexplored area. Aim To assess the relationship between air pollution and the occurrence of ST-elevation myocardial infarction (STEMI) and premature cardiovascular (CVD) mortality incidence. Methods The study area encompassed three voivodeships from Eastern Poland at the NUTS-2 level, with a population of 5,429,378 individuals. Data on hospitalizations from 2011 to 2020 were obtained from the National Health Fund. We combined air pollution and weather condition data from both ground monitoring stations and satellite observations. Hospitalization for STEMI and CVD mortality were identified using ICD-10 codes. We build single and two-pollutant models using negative binomial regression models at the municipality level. To provide a national perspective, we applied meta-analytical strategies to the municipality-specific outcomes. The results are presented as Odds Ratio (OR) with 95% confidence intervals (95% CI). Results During the 10 year period we recorded 63,154 STEMI cases with a median age of 67 years (IQR 59–77) and males constituted 64% of cases. Overall, 377,344 CVD deaths were recorded, with a male proportion of 46.2% and a median age of 82 years (IQR 72–88). In our study, the median concentration of O3 was 47.9 μg/m3 (IQR 34.3–60.9) with great seasonal and geographical variability. The exposure to O3 increased the risk of STEMI incidence on the day of exposure by 2.1% (95%CI 1.002-1.039). Women and the older population were more vulnerable to detrimental effects from O3 exposure, resulting in 3.9% (1.01-1.068) and 2.5% (1.003-1.048) increase in STEMI cases, respectively. Ozone had a significant impact on CVD mortality in both sexes and all ages, showing the greatest impact on people >65 years, with 3.2% increase on the day of exposure (1.012-1.051). These effects persisted for up to 1 day after exposure. In two-pollutant models incorporating particulate matter, NO2, and BaP, the associations remained consistent, indicating the robustness of the observed effects. Conclusions Ozone, although often overlooked, is a significant component of air pollution, with health impacts independent of other factors. Our study highlights the necessity of considering ozone as a distinct and critical aspect in modeling the effects of pollution on health and in shaping health and environmental policies, with special attention devoted to high-risk groups like the elderly.