Associations between grass and weed pollen and emergency department visits for asthma among children in Montreal.
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.
Héguy
Léa
L
Geography Department, Université du Québec à Montréal, Montréal, Que., Canada. lea.heguy@mcgill.ca
Garneau
Michelle
M
Goldberg
Mark S
MS
Raphoz
Marie
M
Guay
Frédéric
F
Valois
Marie-France
MF
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
D000393:Air Pollutants