Associations Between Atmospheric Concentrations of Spores and Emergency Department Visits for Asthma Among Children Living in Montreal

ABSTRACT

The authors carried out a time-series study to determine whether short-term increases in the concentrations of spores were associated with emergency department visits from asthma among children 0 to 9 years of age in Montreal, 1994–2004. Concentrations of spores were obtained from one sampling monitor. The authors used parametric Poisson models to model the association between daily admissions to emergency rooms for asthma and ambient exposures to a variety of spores, adjusting for secular trends, changes in weather, and chemical pollutants. For first admissions and exposures to Basidiomycetes, the authors found positive associations at all lags but the concurrent day. For Deuteromycetes and Cladosporium, risks were positive starting at lag 3 days and diminished at lag 6 days. There was little evidence of associations for readmissions, except for Basidiomycetes. The results indicate that Basidiomycetes and Cladosporium spores may be implicated in the exacerbation of asthma among children, most notably in the case of first-time visits to emergency departments, and that the effects appear to be delayed by several days.

KEYWORDS:

• epidemiology
• outdoor air pollutants
• pediatric asthma
• spores
• time-series study

Acknowledgments

The authors wish to thank the Division of Clinical Epidemiology of McGill University Health Center, the Climate Change Action Fund (Impacts and Adaptation program, project A-571), the Ouranos Consortium (Consortium on Regional Climatology and Adaptation to Climate Change), the Réseau de Surveillance de la Qualité de l'Air de Montréal (Claude Gagnon), and the Meteorological Service of Canada (Québec region). Dr Goldberg gratefully acknowledges receipt of an Investigator Award from the Canadian Institutes for Health Research.