title: Ozone exposure and cardiovascular-related mortality in the Canadian Census Health and Environment Cohort (CANCHEC) by spatial synoptic classification zone.
abstract: Our objective is to analyse the association between long term ozone exposure and cardiovascular related mortality while accounting for climate, location, and socioeconomic factors. We assigned subjects with 16 years of follow-up in the Canadian Census Health and Environment Cohort (CanCHEC) to one of seven regions based on spatial synoptic classification (SSC) weather types and examined the interaction of exposure to both fine particulate matter (PM2.5) and ground level ozone and cause of death using survival analysis, while adjusting for socioeconomic characteristics and individual confounders. Correlations between ozone and PM2.5 varied across SSC zones from -0.02 to 0.7. Comparing zones using the most populated SSC zone as a reference, a 10 ppb increase in ozone exposure was associated with increases in hazard ratios (HRs) that ranged from 1.007 (95% CI 0.99, 1.015) to 1.03 (95% CI 1.02, 1.041) for cardiovascular disease, 1.013 (95% CI 0.996, 1.03) to 1.058 (95% CI 1.034, 1.082) for cerebrovascular disease, and 1.02 (95% CI 1.006, 1.034) for ischemic heart disease. HRs remained significant after adjustment for PM2.5. Long term exposure to ozone is related to an increased risk of mortality from cardiovascular and cerebrovascular diseases; the risk varies by location across Canada and is not attenuated by adjustment for PM2.5. This research shows that the SSC can be used to define geographic regions and it demonstrates the importance of accounting for that spatial variability when studying the long term health effects of air pollution.
authors.affiliation: Population Studies Division, Environmental Health Science & Research Bureau, Health Canada, 50 Columbine Driveway, Ottawa, ON K1A 0K9, Canada. Electronic address: sabit.cakmak@canada.ca.
authors.forename: Sabit
authors.initials: S
authors.lastname: Cakmak
authors.affiliation: Population Studies Division, Environmental Health Science & Research Bureau, Health Canada, 50 Columbine Driveway, Ottawa, ON K1A 0K9, Canada.
authors.forename: Chris
authors.initials: C
authors.lastname: Hebbern
authors.affiliation: Department of Geosciences, Texas Tech University, Box 41053, Lubbock, TX 79409-1053, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Vanos
authors.affiliation: Department of Sociology, University of New Brunswick, PO Box 4400, Fredericton, NB E3B 5A3, Canada.
authors.forename: Dan L
authors.initials: DL
authors.lastname: Crouse
authors.affiliation: Population Studies Division, Environmental Health Science & Research Bureau, Health Canada, 50 Columbine Driveway, Ottawa, ON K1A 0K9, Canada.
authors.forename: Rick
authors.initials: R
authors.lastname: Burnett
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D000397:Air Pollution / Q000032:analysis; D002170:Canada; D002318:Cardiovascular Diseases / Q000401:mortality*; D019352:Censuses; D002980:Climate; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D010126:Ozone / Q000032:analysis / Q000633:toxicity*; D052638:Particulate Matter / Q000032:analysis; D016016:Proportional Hazards Models; D012959:Socioeconomic Factors; D013997:Time Factors; D014887:Weather
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D010126:Ozone
keywords: Air pollution; Cardiovascular; Climate zones; Environmental health; Mortality