title: Association between air pollution and multiple respiratory hospitalizations among the elderly in Vancouver, Canada.
abstract: Recurrent events, such as repeated hospital admissions for the same health outcome, occur frequently in environmental health studies. In this study, we conducted an analysis of data on repeated respiratory hospitalizations among the elderly in Vancouver, Canada, for the period of June 1, 1995, to March 31, 1999, using a new method proposed by (Dewanji and Moolgavkar 2000, 2002) for recurrent events, and compared it with some traditional methods. In particular, we assessed the impact of ambient gaseous (SO2, NO2, CO, and O3) and particulate pollutants (PM10, PM2.5, and PM10-2.5) as well as the coefficient of haze (CoH) on recurrent respiratory hospital admissions. Using the new procedure, significant associations were found between admissions and 3-day, 5-day, and 7-day moving averages of the ambient SO2 concentrations, with the strongest association observed at the 7-day lag (RR = 1.044, 95% CI: 1.018-1.070). We also found PM10-2.5 for 3-day and 5-day lag to be significant, with the strongest association at 5-day lag (RR = 1.020, 95% CI: 1.001-1.039). No significant associations with admission were found with current day exposure.
authors.affiliation: Department of Mathematics and Statistics, University of Windsor, Windsor, Ontario, Canada. kfung@uwindsor.ca
authors.forename: Karen Y
authors.initials: KY
authors.lastname: Fung
authors.forename: Shahedul
authors.initials: S
authors.lastname: Khan
authors.forename: Daniel
authors.initials: D
authors.lastname: Krewski
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000368:Aged; D000393:Air Pollutants / Q000633:toxicity*; D001955:British Columbia; D002248:Carbon Monoxide / Q000633:toxicity; D004787:Environmental Pollution; D006801:Humans; D019570:Inhalation Exposure; D015233:Models, Statistical; D009585:Nitrogen Dioxide / Q000633:toxicity; D010316:Particle Size; D010359:Patient Readmission / Q000706:statistics & numerical data; D012140:Respiratory Tract Diseases / Q000209:etiology*; D012189:Retrospective Studies; D013458:Sulfur Dioxide / Q000592:standards / Q000633:toxicity; D014887:Weather
chemical_list: D000393:Air Pollutants; D013458:Sulfur Dioxide; D002248:Carbon Monoxide; D009585:Nitrogen Dioxide