Heightened bronchial hyperresponsiveness in the absence of heightened atopy in children with current wheezing and low-income status.

Abstract

Background: Although global studies as ISAAC have provided with valuable data on the prevalence of asthma in children of Latin America, there is very few information on the relationship between asthma symptoms, pulmonary function, bronchial hyperresponsiveness and atopy in the region. Methods: This study examined the relationship between self-reported wheezing in the last 12 months, pulmonary function, airway responsiveness and atopy in children from a low-income population neighborhood in Santiago, Chile. Two random samples (100 each) of children aged 13-14 years who participated in ISAAC Phase One were selected according to whether they have reported or not, wheezing in the last 12 months. Spirometry, methacholine bronchial challenge test and prick test were performed in all individuals. Results: Children who reported current wheezing had significantly higher bronchial hyperresponsiveness (BHR) to methacholine as compared to those without wheezing (71.6% vs.52.6%, respectively; p=0.007,) and no significant difference was found in FEV1 (116.7„b12.3% vs. 120.3„b14.5%, respectively, p=0.11). The prevalence of atopy was not significantly different between those children who reported wheezing as compared to those who did not (44.2% vs. 42.3%; respectively, p=0.89). Multiple regression analysis showed that only BHR to methacholine (OR 2.72, 95% CI: 1.25-4.13, p=0.01) and maternal asthma (OR 3.1, 95%CI 1.2-8.3, p=0.03) were significant risk factors for current wheezing. Conclusions: Our results support previous findings suggesting that in adolescents from unprivileged populations, self-reported current wheezing is related to BHR but not to atopy.