Short-Term Exposure to Ambient Air Pollution and Hospital Admission for Stroke: A Multi-Center Hospital-Based Case-Crossover Study

Stroke is a leading cause of death and disability worldwide. Exposure to ambient air pollutants and the risk of stroke have been reported in many studies, but the results vary greatly among different regions. This study aims to investigate the association between short-term exposure to air pollution and the admission of total stroke and its subtypes in the Luohu District, Shenzhen. A time-stratified case-crossover study was conducted among 21,973 newly diagnosed stroke cases in Luohu, Shenzhen from 2014 to 2022. Residential exposure to air pollution was assessed using validated grid datasets. A distributed lag model (DLM) and conditional logistic regression model were implemented to evaluate the relationship between ambient air pollution and the admission of stroke and its subtypes. We found that a 10 µg/m3 increase in exposure to NO2 and SO2 was positively associated with a 2.73% increase (95% confidence interval [CI]: 2.21%, 3.25%) and a 24.89% increase (20.87%, 29.06%) in the odds of total stroke admission, respectively. Statistical significance has also been found in subtypes. Stronger associations were observed in females (SO2), the elderly (NO2 and SO2), and the cold season (NO2 and SO2). Our findings indicate that exposure to NO2 and SO2 exacerbates the risk of stroke admission, especially in the elderly, females, and the cold season.