Abstract

OBJECTIVE: To compare the prevalence ol exercise induced bronchial hyperresponsiveness in Inuit children with that or children in Montreal, and to identify possible genetic and environmental determinants of the differences observed.DESIGN: Cross-sectional survey.SETTING: Salluit, an isolated Inuit community in northern Quebec, and Montreal.POPULATION STUDIED: All children attending school in Salluit in grades 2 to 6 were eligible to participate. For the Montreal study, 18 schools were selected and from each of these one class from each of grades 1, 3 and 5 were chosen.MEASUREMENTS: Data collection for both locations included an exercise challenge test to assess exercise induced bronchial hyperresponsiveness (EIBH), allergy skin testing, a questionnaire for parents regarding details or the home environment as well as the child’s history of respiratory symptoms, and collection of dust samples from the bedroom floor and mattress for the presence of house dust mite.RESULTS: The prevalence or EIBH (defincd as a decline of 15% or more between pre-exercise forced expiratory volume in 1 s [FEV1] and that at 5 or 10 mins postexercise) was 19.5% (23 of 118) among the Inuit children, compared with 8.8% (87 of 989) among the Montreal children. In contrast. only 8.6% of the Inuit children had a positive allergy skin test compared with 34% in Montreal.CONCLUSIONS: A higher prevalence of EIBH was found in Inuit schoolchildren compared with children of similar age in Montreal, although the prevalence of atopy was considerably lower.