Short-term exposure to outdoor air pollution significantly associated with severity of acute ischaemic stroke: evidence from the 4S registry

BACKGROUND: While associations between exposure to air pollution and the prevalence of acute ischaemic stroke (AIS) have been investigated, only a few studies have reported the relationship between air pollution and stroke severity. This study aimed to assess the impact of air pollution on AIS severity based on hourly monitoring data and a stroke-specific registry from 2017 to 2021 in Shanghai. METHODS: were monitored from 2017 to 2021. A conditional logistic regression model and a Quasi-Poisson model, both coupled with a distributed lag non-linear model and a time-stratified case-crossover design, were used to evaluate a cohort of 106 623 AIS events documented within the Shanghai Stroke Service registry correspondingly. Counterfactual analyses were applied to reveal the potential reducible fractions (PRFs) of air pollution on baseline National Institute of Health Stroke Scale (NIHSS). RESULTS: 4.04% (95% CI 3.04% to 5.03%), p<0.001). Quasi-Poisson analysis showed similar results. CONCLUSIONS: , was shown to increase AIS severity. This finding underscored the need for targeted emission controls and stroke prevention strategies.