Short-term exposure to air pollution and occurrence of emergency stroke in Chongqing, China

Objective This study aimed to study the relationship between air pollution and stroke (especially emergency stroke) in different regions and determine which air pollutant is the most significantly associated with stroke. Methods The number of patients with emergency stroke, air pollutant data and related meteorological indicators were collected from December 2013 to May 2018 for large comprehensive hospitals in Chongqing. The generalized additive model was used to analyse the relationship between air pollution and emergency stroke. Results After analysis and adjusting for meteorological indicators and day-of-the-week effects, in the one-pollutant model, every 10 μg/m 3 increase in ozone(O 3 ) was associated with a 2.482% (95% CI 1.044%, 3.919%) change in emergency strokes within lag0. For males, every 10 μg/m 3 increase of O 3 contributed to a 0.77% percent greater change compared with females. For the group younger than 60 years, we observed a 1.14% increase in risk with every 10 μg/m 3 increase in O 3 . The group with pre-existing hypertension had a 0.26% higher risk than the group with no pre-existing hypertension with every 10 μg/m 3 increase in O 3 . In two-pollutant model, when O 3 was combined with a 10 μg/m 3 increase of NO 2 , it increased the most significant risk of emergency stroke by 0.22%. Conclusion These findings suggest that short-term exposure to O 3 within 0 days is associated with emergency outpatient strokes, and younger people (age < 60 years) males and people with hypertension are more sensitive than older people, females and people without pre-existing hypertension.