Post-Discharge Ambient Sulfur Dioxide Exposure and Stroke Recurrence After Acute Ischemic Stroke

Background and purpose: Ambient air pollution is an established risk factor for incident stroke, but whether post-discharge pollutant exposure influences stroke recurrence remains unclear. We investigated the association between post-discharge exposure to six ambient air pollutants and stroke recurrence after acute ischemic stroke.

Methods

We analyzed 27,340 patients in the Clinical Research Collaboration for Stroke in Korea-National Institutes of Health nationwide multicenter registry (2014-2021). The 3-month post-discharge district-level mean concentrations of particulate matter ≤10 μm (PM10), ≤2.5 μm (PM2.5), nitrogen dioxide, sulfur dioxide (SO2), carbon monoxide, and ozone were estimated by inverse-distance-weighted interpolation. The primary outcome was stroke recurrence from 3 to 15 months post-discharge. Cause-specific Cox models with cluster-robust standard errors were used, treating death as a competing risk; non-linear dose-response was assessed by restricted cubic splines.