Environmental factors and asthma and allergy in schoolchildren from Western Australia.

The association of environmental factors with atopic disease in children remains poorly understood. The aim of this study was to investigate the relationship between socio-environmental factors and symptoms of asthma and atopy in 6-7-yr-old children assessed as an adjunct to Phase I of the International Study of Asthma and Allergy in Childhood in Perth, Western Australia. Parental questionnaire responses were obtained for 2,193 children (73.6%) in 34 randomly selected primary schools in the Perth metropolitan area. Children born in Australia had a significantly increased risk of current asthma (odds ratio (OR) 237, p = 0.001). Having a mother born in Australia was the only factor independently associated with an increased risk of current hay fever (OR 1.56, p = 0.005). Increasing numbers of people living in the home were significantly associated with a multiplicative decrease in risk of current asthma (OR 0.88, p = 0.03) and eczema (OR 0.82, p = 0.01). Houses made of fibrocement (OR 2.40, p = 0.02) and the presence of mats on less than half of the floor area in the "main bedroom" (relative to wall-to-wall carpet) (OR 3.50, p = 0.003) were associated with an increased risk of current eczema. All reported associations were independent of socioeconomic status (categorized by school), age and sex. This study suggests that household and country-specific environmental factors are associated with asthma, hay fever and eczema risk in 6-7-yr-old schoolchildren, and may have substantially contributed to the increased prevalence of these diseases in Australia.