Global Changes in Ischemic Stroke Burden Attributable to Ambient PM2.5: Trends From 1990 to 2020 and Projections to 2050.

BACKGROUND AND OBJECTIVES Ischemic stroke (IS) is a leading cause of disability and mortality worldwide, with ambient fine particulate matter (PM2.5) exposure being a significant modifiable risk factor. While PM2.5 concentrations have declined in some regions, global assessments examining how these changes affect the IS burden remain limited. The aim of this study was to quantify changes in IS burden attributable to PM2.5 from 1990 to 2020 and project future trends to 2050. METHODS We used data from the 2021 Global Burden of Disease study, including population estimates, IS incidence rates, and PM2.5 concentrations, for 204 countries and World Bank regions. The Environmental Benefits Mapping and Analysis Program algorithm was applied to estimate IS cases attributable to PM2.5. Future projections were calculated using an autoregressive integrated moving average model. RESULTS Between 1990 and 2020, global PM2.5 concentrations decreased by 8.18 μg/m3. This reduction was associated with approximately 920,245 avoided IS cases, equivalent to 12.11% of the global IS incidence in 2020. The East Asia and Pacific region experienced the greatest benefit, with 699,218 IS cases avoided (19.09% of the region's IS incidence in 2020). By 2050, PM2.5 concentrations are projected to decline by 33.64 μg/m3 relative to 1990, potentially preventing an additional 6,004,854 IS cases. However, significant disparities persist, particularly in low-income regions where PM2.5 exposure and limited health care infrastructure continue to pose challenges. DISCUSSION Our findings highlight the substantial public health benefits of PM2.5 reductions in mitigating the IS burden. While high-income regions have seen substantial gains due to stringent air quality regulations, low-income regions remain disproportionately affected. Addressing these disparities requires targeted pollution control policies and equitable health care resource allocation. Sustained efforts in air quality management are critical to reducing the global IS burden and improving health outcomes, particularly in vulnerable populations.