Acute viral bronchiolitis and risk of asthma in schoolchildren: analysis of a Brazilian newborn cohort

Abstract

Objective: To verify whether the occurrence of acute viral bronchiolitis (AVB) in the first year of life constitutes a risk factor for asthma at age 6 considering a parental history of asthma. Methods: Cross-sectional study in a cohort of live births. A standardized questionnaire of the International Study of Asthma and Allergies in Childhood (ISAAC) was applied to the mothers to identify asthma in children at the age of 6 years. AVB diagnosis was performed by maternal report of a medical diagnosis and/or presence of symptoms of coryza accompanied by cough, tachypnea, and dyspnea when participants were 3, 6, 9, and 12 months. Socioeconomic, environmental data, parental history of asthma, and data related to pregnancy were collected in the first 72 hours of life of the newborn and in prospective home visits by trained interviewers. The association between AVB and asthma was evaluated by logistic regression analysis and potential modifier effect of parental history was verified by introducing an interaction term into the adjusted logistic regression model. Results: Prevalence of AVB in the first year of life was 68.6% (461). The occurrence of AVB was a risk factor for asthma at 6 years of age in children with parental history of asthma OR: 2.66, 95% CI (1.10-6.40), modifier effect p = 0.002. Parental history of asthma OR: 2.07, 95% CI (1.29-3.30) and male gender OR: 1.69, 95% CI, (1.06-2.69) were other identified risk factors for asthma.