title: The Air Quality Health Index as a predictor of emergency department visits for ischemic stroke in Edmonton, Canada.
abstract: The Air Quality Health Index (AQHI) is an aggregate measure of outdoor air quality. We investigated associations between the AQHI and emergency department (ED) visits for acute ischemic stroke to validate the AQHI as a predictor of risk of morbidity from stroke. ED visits in Edmonton, Canada between 1998 and 2002 were linked to hourly AQHI values and concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), ozone, particulate matter with aerodynamic diameter less than 2.5 and 10 μm, and sulfur dioxide. A time-stratified case-crossover analysis was employed, and measures of association were adjusted for temperature and relative humidity. The AQHI, NO2 and CO were positively associated with the number of ED visits for ischemic stroke during April-September, and associations were strongest for persons 75 years of age and older. In this age range, the odds ratios (95% confidence intervals) for an interquartile range increase of AQHI in 1-24 h, 25-48 h, and 1-72 h lag periods were 1.23 (1.08-1.40), 1.15 (1.01-1.31), and 1.30 (1.10-1.54), respectively. Significant positive associations were also observed for NO2 and CO. Our finding that ED visits for stroke were significantly associated with the AQHI suggests that the AQHI may be a valid communication tool for air pollution morbidity effects related to stroke.
authors.affiliation: Population Studies Division, Healthy Environments and Consumer Safety Branch, Health Canada, 200 Eglantine Driveway, 1915B, Ottawa, Ontario, Canada K1A 0K9.
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.affiliation: 1] Population Studies Division, Healthy Environments and Consumer Safety Branch, Health Canada, 200 Eglantine Driveway, 1915B, Ottawa, Ontario, Canada K1A 0K9 [2] Department of Health Sciences, Carleton University, Ottawa, Ontario, Canada K1S 5B6155.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Villeneuve
authors.affiliation: Department of Emergency Medicine and School of Public Health, University of Alberta, Emergency Operational Clinical Network, Alberta Health Services, University of Alberta Hospital, Edmonton, Alberta, Canada T6G 2B7.
authors.forename: Brian H
authors.initials: BH
authors.lastname: Rowe
authors.affiliation: Population Studies Division, Healthy Environments and Consumer Safety Branch, Health Canada, 200 Eglantine Driveway, 1915B, Ottawa, Ontario, Canada K1A 0K9.
authors.forename: Ling
authors.initials: L
authors.lastname: Liu
authors.affiliation: Population Studies Division, Healthy Environments and Consumer Safety Branch, Health Canada, 4595 Canada Way, Burnaby, British Columbia, Canada V5G 1J9.
authors.forename: David M
authors.initials: DM
authors.lastname: Stieb
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000416:Alberta / Q000453:epidemiology; D002545:Brain Ischemia / Q000139:chemically induced / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D016273:Occupational Exposure; D052638:Particulate Matter / Q000633:toxicity*; D020521:Stroke / Q000139:chemically induced / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D052638:Particulate Matter