Objectives To investigate the association between air pollutants and emergency hospital visits (EHVs) for stroke in Changsha, China.
Methods The daily EHVs for stroke were gathered from the third Xiangya hospital during 2008-2009. The corresponding air pollutants, meteorological data were collected. The seasonal-stratified case-crossover design with 1:1 matched pair was used to set up single-pollution models and multi-pollution models for the data analysis.
Results After adjusting the temperature and relative humidity in single-pollution models, sulfur dioxide (SO2) and particulate matters with an aerodynamic diameter of <10 μm (PM10) were significantly association with EHVs of cerebral haemorrhage and cerebral infarction at lags of 0, 1 and 2 days in autumn. The best lag days for the effect of SO2 on cerebral haemorrhage (OR = 1.466, 95%CI: 1.139-1.887) and cerebral infarction (OR = 1.514, 95%CI: 1.223-1.873) were lag 2 days and 0 day respectively. There were no significantly association between air pollutants and EHVs for stroke in spring, summer and winter. In multi-pollution models, an 10 μg/m3 increase in SO2 were significantly association with EHVs of cerebral infarction (OR = 1.587, 95%CI: 1.145-2.200) after controlling for PM10 and NO2 in autumn. In other seasons, there were no significantly association between air pollutants and EHVs for stroke.
Conclusions Elevated the concentration of SO2, NO2 and PM10 in autumn were associated with EHVs for stroke in Changsha.