Heat exposure and hospitalisation for epileptic seizures: A nationwide case-crossover study in Brazil

Climate change is increasing human exposure to heat, especially in tropical regions such as Brazil where temperature reaches up to 40 degrees C in summer. However, the association between heat exposure and epileptic seizures has not been well demonstrated in Brazil, where lifetime preva-lence of epilepsy can range from 11.9/1000 to 21/1000. We collected a total of 225,699 hospi-talisation records for epileptic seizures of 1816 municipalities in Brazil, during the hot season from 2000 to 2015, covering nearly 79% of the national population. We implemented a time -stratified case-crossover design combined with distributed lag model with further stratified in-vestigations regarding sex, age, socioeconomic status and region. We found temperature impact threshold was 26 degrees C in Brazil nationally. Every 1 degrees C increase from the threshold was associated with an overall 4.3% increased risk of hospitalisation for epileptic seizures on the current day of hospital admission and up to seven days before, which was most pronounced on the second-day exposure to heat. Females, individuals aged 20-30 and persons living in high-income or Southeast regions were more vulnerable. Our results highlight the enhanced risk of heat exposure for epi-lepsy patients and could contribute to epilepsy management, such as forecasting epileptic sei-zures. Multi-dimensional adaptive strategies were proposed, covering individual protection, occupational health surveillance, and urban planning management, aiming to reduce heat -induced hospitalisations for epilepsy, and be generalizable to other heat-related diseases.