Short-Term PM2.5 Exposure and Ischemic Heart Disease Mortality: A Multicenter Study in Three Cities of Liaoning Province

Objective To investigate the impact of short-term exposure to fine particulate matter (PM2.5) on ischemic heart disease (IHD) mortality in three cities of Liaoning Province, China.Methods Daily mortality data for ischemic heart disease (ICD-10 codes I20-I25) were collected for Shenyang (2013-2022), Dandong (2016-2022), and Benxi (2015-2022), along with concurrent environmental protection and meteorological data. Generalized additive models (GAM) with quasi-Poisson regression were employed to analyze the association between PM2.5 and IHD mortality in each city. Single-day lag models (lag0 to lag3) and moving average lag models (lag01 and lag03) were used to examine immediate and cumulative lag effects. Random-effects meta-analysis was applied to pool the effect estimates across the three cities. Stratified analyses were conducted to assess the effects by sex, age group, and season.Results During the study periods, the daily average IHD deaths were 22.6 in Shenyang, 6.1 in Dandong, and 12.5 in Benxi. In the single-day lag analysis, the maximum pooled effect estimate occurred at lag0. For each 10 μg/m3 increase in PM2.5 concentration, IHD mortality significantly increased by 0.98% (95% CI: 0.42%, 1.23%). For the cumulative lag effect at lag01, IHD mortality significantly increased by 1.09% (95% CI: 0.62%, 1.57%). Stratified analyses revealed that these effects were more pronounced during the warm season, among females, and among individuals aged 65 years and older. The city with lower pollution levels (Dandong) exhibited a higher excess risk.Conclusion Short-term exposure to PM2.5 is associated with increased IHD mortality in the three studied cities of Liaoning Province. The effects were stronger in the warm season, among females, the elderly, and in the less polluted city.