Regional variations in risk factors for asthma in school children.
BACKGROUND
The authors have previously reported an increased prevalence of asthma in Estevan, Saskatchewan (21.4%) compared with Swift Current, Saskatchewan (16.2%).


OBJECTIVE
To determine the association between asthma and personal and indoor environmental risk factors in these communities.


METHODS
A population-based cross-sectional study was conducted in January 2000. A questionnaire was distributed to school children in grades 1 to 6 for completion by a parent. Multivariate logistic regression was used to examine associations between various risk factors and physician-diagnosed asthma.


RESULTS
Asthma was associated with respiratory allergy (adjusted OR [adjOR]=8.85, 95% CI 6.79 to 11.54), early respiratory illness (adjOR=2.81, 95% CI 1.96 to 4.03) and family history of asthma (adjOR=2.37, 95% CI 1.67 to 3.36). Several environmental factors varied with asthma by town. In Estevan, asthma was associated with home mould or dampness (adjOR=1.82, 95% CI 1.23 to 2.69) and was inversely associated with air conditioning (adjOR=0.56, 95% CI 0.37 to 0.85). The risk of asthma was increased if the child had previous exposure to environmental tobacco smoke from the mother in both communities (Swift Current: OR=1.87, 95% CI 1.06 to 3.30; Estevan: OR=2.00, 95% CI 1.17 to 3.43), and there was an inverse association with current exposure to environmental tobacco smoke from the mother in Estevan (OR=0.64, 95% CI 0.40 to 1.00). When multivariate analyses were stratified by sex, the relationship between home mould or dampness and asthma was most prominent in girls in Estevan.


CONCLUSIONS
Despite a similar regional location, different risk factors for asthma were identified in each community. Local environmental factors are important to consider when interpreting findings and planning asthma care.
Lawson
Joshua A
JA
Institute of Agricultural, Rural and Environmental Health, University of Saskatchewan, Saskatoon. lawson@sask.usask.ca
Rennie
Donna C
DC
Senthilselvan
Ambikaipakan
A
Cockcroft
Donald W
DW
McDuffie
Helen H
HH
D001249:Asthma / Q000453:epidemiology*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D012307:Risk Factors; D012525:Saskatchewan / Q000453:epidemiology; D011795:Surveys and Questionnaires