Abstract Background Increased ground-level ozone (O₃) contributes to global warming, while climate change enhances its formation. Although high O₃ levels are linked to increased mortality, their association with cardiovascular diseases (CVD) remains unclear. Purpose This study aims to assess the impact of summer exposure to O₃ on the incidence of major cardiovascular events (MACE). Methods A geospatial analysis was conducted on the EP-PARTICLES cohort, integrating over 5 million hospitalizations and deaths due to CVD (2011-20). The primary endpoint included MACE, defined as the composite occurrence of CVD-related death, STEMI, or NSTEMI. All analyses were conducted using individual-level hospitalization and mortality data. Information on pollutants was obtained from satellites and local monitoring stations using the GEM-AQ model, providing estimates with a 24-hour and 1×1 km² resolution. A negative binomial regression model was used. The final model was adjusted for the day of the week, public holidays, weather conditions. Given that O₃ pollution primarily affects the summer months, the analysis included the extended summer season, defined as June 1-Sept 30. Stratified analyses were conducted according to sex, age, socioeconomic status (SES) and area characteristics. Results are presented as Risk Ratios (RRs) for an interquartile range (IQR) increase in pollutant concentrations, with 95% confidence intervals (95% CI). Results Total recorded deaths were 831,246, including 377,344 CVD deaths. Final analysis of the summer periods included 112,907 (29.9%) CVD mortality cases (median age: 82 years, IQR: 72–88, 46.4% male), 18,947 STEMI cases and 25,287 of NSTEMI. During the summer period, the median concentration of O₃ was 59.00 µg/m³ (IQR: 19.05 µg/m³). Each IQR increase of O₃ concentration on the day of exposure resulted in a 2.7% (95%CI 1.020-1.035), 3.6% (1.026−1.046), and 3.5% (01.011−1.06) increase in MACE, CVD, and STEMI, respectively. As for sex differences, women were more vulnerable to O₃ in terms of NSTEMI on the day of exposure (ratio of RR: 1.054; 95%CI 1.009-1.102, p=0.019), as well as on the following days (lag3 p=0.036). Moreover, women also suffered more from O₃-related MACE over the next days following exposure with lag2 RRR of 1.016 (1.002-1.031) and lag3 RRR 1.015 (1.00-1.03). Younger individuals were affected more by O₃ exposure in terms of CVD mortality (RRR for lag0-6: 1.055, 95%CI 1.006-1.106). There were no significant differences based on SES status or place of residence (rural vs. urban area). Conclusions Summer exposure to O₃ is associated with an increased incidence of MACE, with young women being the most at-risk phenotype. The impact of O₃ is independent of area setting and SES conditions, indicating a global concern. Climate change presents new challenges for preventive cardiology in temperate regions, highlighting the need for air quality monitoring and the implementation of preventive strategies, also during summer months.
Kurasz et al. (Sat,) studied this question.