European journal of epidemiology
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Inconsistent results have been obtained from studies that have examined the relationship between air pollution and hospital visits for stroke. We undertook a time-stratified case-crossover study to evaluate associations between outdoor air pollution and emergency department visits for stroke among the elderly according to stroke type, season, and sex. Analyses are based on a total of 12,422 stroke visits among those 65 years of age and older in Edmonton, Canada between April 1, 1992 and March 31, 2002. ⋯ During this season, the ORs associated with an increase in the IQR of the 3-day average for CO and NO(2) were 1.32 (95% CI = 1.09-1.60) and 1.26 (95% CI = 1.09-1.46), respectively. CO exposures in the same season, lagged 1 day, were associated with an increased risk of hemorrhagic stroke with ORs was 1.20 (95% CI = 1.00-1.43). Our results suggest it is possible that vehicular traffic, which produces increased levels of NO(2) and CO, contributes to an increased incidence of emergency department visits for stroke.