title: Associations between grass and weed pollen and emergency department visits for asthma among children in Montreal.
abstract: OBJECTIVE
  Asthma among children is a major public health problem worldwide. There are increasing number of studies suggesting a possible association between allergenic pollen and exacerbations of asthma. In the context of global climate change, a number of future climate and air pollution scenarios predict increases in concentrations of pollen, an extension of the pollen season, and an increase in the allergenicity of pollen. The goal of the present study is to evaluate the short-term effects of exposure to grass and weed pollen on emergency department visits and readmissions for asthma among children aged 0-9 years living in Montreal between April and October, 1994-2004.
  
  
  RESULTS
  Time-series analyses were carried out using parametric log-linear overdispersed Poisson models that were adjusted for temporal variations, daily weather conditions (temperature, atmospheric pressure), and gaseous air pollutants (ozone and nitrogen dioxide). We have found positive associations between emergency department visits and concentrations of grass pollen 3 days after exposure. The effect of grass pollen was higher on emergency department readmissions as compared to initial visits. Weak negative associations were found between weed pollen (including ragweed pollen) and emergency department visits 2 days after exposure.
  
  
  CONCLUSIONS
  The data indicate that among children, emergency department visits increased with increasing concentrations of grass pollen.
authors: Geography Department, Université du Québec à Montréal, Montréal, Que., Canada. lea.heguy@mcgill.ca
authors: Léa
authors: L
authors: Héguy
authors: Michelle
authors: M
authors: Garneau
authors: Mark S
authors: MS
authors: Goldberg
authors: Marie
authors: M
authors: Raphoz
authors: Frédéric
authors: F
authors: Guay
authors: Marie-France
authors: MF
authors: Valois
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects* / Q000032:analysis; D031164:Ambrosia / Q000009:adverse effects; D001249:Asthma / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D002648:Child; D002669:Child Welfare; D002675:Child, Preschool; D016208:Databases, Factual; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D006109:Poaceae / Q000009:adverse effects; D011058:Pollen / Q000009:adverse effects* / Q000737:chemistry; D011792:Quebec / Q000453:epidemiology
chemical_list: D000393:Air Pollutants