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 µg/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 PM(2.5), 1.054 (95% CI 1.031 to 1.077) for NO(2) 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 PM(2.5), NO(2) and O(3) may induce stroke morbidity, and the government should take actions to mitigate air pollution and protect sensitive populations.