Paternal Asthma, Mold Exposure, and Increased Airway Responsiveness Among Children With Asthma in Costa Rica

BackgroundLittle is known about the determinants of airway hyperresponsiveness (AHR) among children with asthma in Hispanic America.MethodsWe examined the relations among selected familial and environmental factors, markers of allergy, spirometric measures of lung function, and AHR in a cross-sectional study of 403 Costa Rican children with asthma between the ages of 6 and 14 years. Study participants completed a protocol that included questionnaires, spirometry, measurements of serum total and allergen-specific IgE, peripheral blood eosinophil count, and body mass index, and the assessment of airway responsiveness to methacholine (ie, a methacholine challenge test [MCT]). AHR to MCT was defined as the provocative dose of methacholine causing a 20% fall in FEV1. Linear regression was used for the univariate and multivariate analyses.ResultsOf the 403 asthmatic children who underwent an MCT, 350 (86.8%) had AHR to methacholine. In a multivariate analysis, paternal asthma (p = 0.004), parental report of mold/mildew in the child's home (p = 0.04), FEV1/FVC ratio (p < 0.0001), and a positive IgE response to Der p 1 (p = 0.008) were significantly associated with AHR among Costa Rican children with asthma.ConclusionOur results suggest that paternal asthma and environmental exposure to mold/mildew are strong determinants of AHR in Costa Rican children with asthma. FEV1/FVC ratio may be a useful measure of AHR (a marker of asthma severity) among Costa Ricans and other Hispanic Americans for whom reference values for FEV1 are not currently available.