Short-term associations between ambient air pollution and stroke hospitalisations: time-series study in Shenzhen, China

Objective To investigate the association between ambient air pollution and stroke morbidity in different subgroups and seasons. Methods We performed a time-series analysis based on generalised linear models to study the short-term exposure-response relationships between air pollution and stroke hospitalisations, and conducted subgroup analyses to identify possible sensitive populations. Results For every 10 mu g/m(3) increase in the concentration of air pollutants, across lag 0-3 days, the relative risk of stroke hospitalisation was 1.029 (95% CI 1.013 to 1.045) for PM2.5, 1.054 (95% CI 1.031 to 1.077) for NO2 and 1.012 (95% CI 1.002 to 1.022) for O 3. Subgroup analyses showed that statistically significant associations were found in both men and women, middle-aged and older populations, and both cerebral infarction and intracerebral haemorrhage. The seasonal analyses showed that statistically significant associations were found only in the winter. Conclusions Our study indicates that short-term exposure to PM2.5, NO2 and O-3 may induce stroke morbidity, and the government should take actions to mitigate air pollution and protect sensitive populations.