Influence of outdoor aeroallergens on hospitalization for asthma in Canada

Robert E. Dales, MD, MScabc, Sabit Cakmak, PhDc, Stan Judek, MScc, Tom Dann, BESc, MEngd, Frances Coates, MLTe, Jeffrey R. Brook, PhDd, Richard T. Burnett, PhDc

Author address: 

a University of Ottawa, Ottawa, Ontario, Canada b Ottawa Health Research Institute, Ottawa, Ontario, Canada c Health Canada, Ottawa, Ontario, Canada d Environment Canada, Ottawa, Ontario, Canada e Aerobiology Research Laboratories, Ottawa


Background The risk of hospitalization for asthma caused by outdoor aeroallergens is largely unknown. Objective The objective of this study was to determine the association between changes in outdoor aeroallergens and hospitalizations for asthma from the Pacific coast to the Atlantic coast of Canada. Methods A daily time series analysis was done to test the association between daily changes in aeroallergens and daily changes in hospitalizations for asthma during a 7-year period between 1993 and 2000 in 10 of the largest cities in Canada. Results were adjusted for long-term trends, day of the week, climate, and air pollution. Results A daily increase, equivalent to the mean value of each allergen, was associated with the following percentage increase in asthma hospitalizations: 3.3% (95% CI, 2.3 to 4.1) for basidiomycetes, 3.1% (95% CI, 2.8 to 5.7) for ascomycetes, 3.2% (95% CI, 1.6 to 4.8) for deuteromycetes, 3.0% (95% CI, 1.1 to 4.9) for weeds, 2.9% (95% CI, 0.9 to 5.0) for trees, and 2.0% (95% CI, 1.1 to 2.8) for grasses. After accounting for the independent effects of trees and ozone, the combination of the 2 was associated with an additional 0.22% increase in admissions averaged across cities (P

abstract No: 

Page 303-306

Full conference title: 

2004 American Academy of Allergy, Asthma, and Immunology Annual Meeting
    • AAAAI 2004 (60th)