Predictors of early and late onset asthma in a rural population of children: The Saskatchewan Rural Health Study

Abstract

Background: Certain environmental and familial factors are known to be predictive or protective of asthma in children. We investigated the relationship between risk factors for asthma in children and whether or not these were associated with early or later onset asthma. Methods: Parents of 2383 children living in rural farming regions of Saskatchewan, Canada completed a questionnaire survey evaluating respiratory disease in school age children. Questionnaires were distributed through schools to parents. Data was available for 354 children ages 6 to 17 years with a history of doctor diagnosed asthma. Age of onset of asthma was categorized as either a diagnosis of asthma before the age of 6 (early) or at 6 years or later (late). Independent variables included living on a farm in the first year of life, current location of home (farm/acreage or other), early daycare attendance, sib ship, breastfeeding, history of respiratory allergies, maternal asthma, prenatal smoking, and maternal education (≤ grade 12 or post-secondary) Results: Most children had early onset asthma (75.2%). Neither allergy nor parental allergy differed by earlier or late onset asthma. Prenatal smoking (p Conclusion: While a history of allergy may not be time dependent for asthma onset, farm exposure may be more limited to preventing early asthma onset.