Risk of Stroke Associated with Temperature and PM2.5: Taiwan Stroke Registry-based Study

This study aimed to assess seasonal stroke risks related to temperature and PM2.5 in Taiwan. Using data of the Taiwan Stroke Registry and air pollution monitored in 2006-2017, the researchers estimated daily average ischemic and hemorrhagic strokes according to temperature and PM2.5 levels, evaluating stroke risks by categorizing PM2.5 levels in each temperature zone. The results revealed a higher incidence of ischemic strokes in February and a higher incidence of hemorrhagic strokes in January, both decreased to the lowest in July. The study found that incident strokes increased with the PM2.5 level in each temperature zone except for the 30+°C stratum. The highest incidence of ischemic strokes appeared at PM2.5 greater than 37.0 μg m–3 during 20-24°C, whereas the highest incidence of hemorrhagic strokes appeared at PM2.5 greater than 37.0 μg m–3 at less than 15°C. No adjusted RRs of strokes were significantly associated with PM2.5 in all temperature zones after controlling for sex, age, BMI, smoking and drinking. We conclude that stroke incidence decreases as the weather gets warmer, whereas PM2.5 pollution may have little effect on stroke incidence. It is essential to keep warm during cold days.