Supplementary Material for: Short-term exposure to ambient air pollution and epilepsy mortality: a population-based case-crossover study

Introduction: As one of the most prevalent neurological disorders, epilepsy imposes a major health burden. Emerging evidence suggests a possible association between air pollution and epilepsy incidence, but its effect on epilepsy-related deaths remains unknown.
Methods: We conducted an individual-level time-stratified case-crossover study in Jiangsu province, China (2015–2022) to explore the associations between short-term exposure to air pollution and epilepsy deaths, focusing on fine particulate matter (PM2.5), inhalable particulate matter (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO) and ozone (O3). Exposure at each subject’s residential address was assessed by extracting concentrations from ChinaHighAirPollutants (CHAP), a series of validated gridded datasets with a high spatial resolution (1 km × 1 km). Conditional logistic regression models were fitted to quantify exposure-response associations. The attributable fraction (AF) and attributable number (AN) from air pollution were calculated to estimate their disease burden.
Results: Each interquartile range (IQR) increase in exposure to PM2.5 (IQR: 32.6 μg/m3), PM10 (IQR: 51.3 μg/m3), SO2 (IQR: 8.5 μg/m3), NO2 (IQR: 20.8 μg/m3) and CO (IQR: 0.3 mg/m3) was significantly associated with a 10.6% (95%CI: 2.9%, 18.9%), 10.5% (2.8%, 18.8%), 9.9% (0.5%, 20.1%), 9.8% (1.2%, 19.2%) and 8.5% (0.5%, 17.1%) higher odds of epilepsy death (all P < 0.05). The association between PM2.5 exposure and epilepsy deaths was significantly stronger among individuals < 50 years. Up to 12.3% of epilepsy deaths were attributable to air pollution.
Conclusion: Exposure to ambient air pollution was significantly associated with increased odds of epilepsy death, especially for younger individuals.