Short-term effect of air pollution on childhood epilepsy in eastern China: A space-time-stratified case-crossover and pooled analysis

Background: Growing studies suggest that air pollution exposure is an emerging driver for neurological diseases, but existing evidence on the association between air pollution and epilepsy is scarce. Here, we aimed to quan-titatively estimated the short-term effects of various air pollutants on childhood epilepsy hospitalizations in China. Methods: We obtained daily electronic health records on childhood epilepsy hospitalizations and air pollutants (PM2.5, PM10-2.5, PM10, SO2, NO2, O3) from 2016 through 2018 in 10 cities of Anhui Province in China. In the first stage, a space-time-stratified case-crossover analysis was employed to evaluate the short-term association of childhood epilepsy hospitalizations with each air pollutant in Anhui Province. In the second stage, short-term effect of air pollution on childhood epilepsy morbidity reported in Anhui Province and in previous studies was pooled with a random-effect meta-analysis model to get the overall effect of different air pollutants in eastern China. Results: This study included 8,181 childhood epilepsy patients from 10 cities in Anhui province of China. The first stage case-crossover analysis in Anhui province found significant associations between higher concentrations of all air pollutants (except O3) and increased risk of childhood epilepsy hospitalizations. Each 10 mu g/m3 increase in PM2.5, PM10-2.5, PM10, SO2, and NO2 concentrations was associated with an increase of 1.1 % [95 % confidence interval (CI): 0.1 %-2.1 %], 1.7 % (95 %CI: 0.5 %-2.9 %), 0.8 % (95 %CI: 0.1 %-1.4 %), 8.5 % (95 %CI: 1.5 %-16.0 %), and 4.3 % (95 %CI: 2.3 %-6.3 %) in epilepsy hospitalizations, respectively. We also observed greater effects of particulate matter in cold season. The second stage meta-analysis that additionally included two prior studies with 43,002 patients from other 11 cities found a marginally significant increase in childhood epilepsy attacks associated with PM2.5, PM10, and NO2 in eastern China. Conclusions: Short-term exposure to both particulate matter and gaseous air pollution was associated with an increased risk of childhood epilepsy exacerbation in eastern China. Our findings suggest that air pollution exposure especially in cold season needs to be considered by children's parents or guardians to prevent epilepsy attacks.