Objective To investigate the risks of total,hemorrhagic and ischemic stroke mortalities associated with shortterm exposure to air pollution,and to determine the susceptible population.
Methods In this study,daily stroke mortalities of adults aged over 50 between 2003 and 2008 in Shanghai were collected.Time-stratified case-crossover approach was used to assess the association between daily concentrations of air pollutants and stroke mortalities.
Results The mortalities from different stroke types were found to be significantly associated with all the examined air pollutants.A significantly higher risk of ischemic stroke mortality in relation to SO2 and NO2 exposure was observed among people with cardiac diseases than those without;for an increase of 10 μg/m3 in SO2 and NO2,the OR values of ischemic stroke mortality for people with cardiac diseases were 1.057(1.010-1.107) and 1.076(1.023-1.131) respectively.No evidence of effect modification was found among people with hypertension and diabetes.
Conclusion This study provides new evidence for the association between exposure to ambient air pollution and stroke mortality.The results also suggest that underlying cardiac disorder may increase the risk of ischemic stroke mortality in relation to air pollution exposure.