Objective: To assess risk factors for wheezing in infants in southern Brazil.
Methods: Cross-sectional study using a standardized and validated questionnaire (Estudio Internacional de Sibilancias en Lactantes, EISL, or International Study of Wheezing in Infants). Parents of infants aged 12-15 months who attended 35 of 107 health centers between August 2005 and December 2006 for regular immunization were interviewed. The association between wheezing and factors studied was made using a prevalence ratio (PR) and confidence interval of 95% (95%CI) to perform a univariate analysis. Factors associated with wheezing in the bivariate analysis were studied using Poisson regression.
Results: Three thousand and three parents of infants filled out the questionnaire. The risk factors were male gender (PR = 1.14; 95%CI 1.05-1.24), history of asthma in the family [mother (PR = 1.18; 95%CI 1.04-1.33); father (PR = 1.20; 95%CI 1.05-1.39); siblings (PR = 1.23; 95%CI 1.08-1.42)], other pets in the home during pregnancy (PR = 1.28; 95%CI 1.07-1.53), age when child started daycare [0-3 months (PR = 1.15; 95%CI 0.98-1.34); 4-6 months (PR = 1.39; 95%CI 1.24-1.55); 7-12 months (PR = 1.20; 95%CI 1.07-1.35)], six or more episodes of cold (PR = 1.32; 95%CI 1.21-1.44), personal history of dermatitis (PR = 1.09; 95%CI 1.003-1.19), and mold in the home (PR = 1.14; 95%CI 1.04-1.24). Up-to-date immunization (PR = 0.79; 95%CI 0.63-0.98) and bathroom in the home (PR = 0.83; 95%CI 0.68-1.01) were protective factors.
Conclusions: Independent risk factors for wheezing in the first year of life are also known risks for asthma in children and adolescents. These data are useful to predict the diagnosis of asthma and to promote its prevention (when applicable).