Prevalence and severity of wheezing in the first year of life in the city of Santo André, Brazil

OBJECTIVE: To determine the prevalence and the severity of wheezing in the first year of life for infants who live in Santo André, São Paulo, Brazil. METHODS: Cross sectional study with the administration of the Estudio Internacional de Sibilancias en Lactantes (EISL), which is a standardized and validated written questionnaire applied to parents and/or guardians of infants aged 12-24 months treated at primary health units, vaccination centers, day care centers, or kindergartens. The questionnaire consisted of questions regarding demographic characteristics, presence of wheezing, respiratory infections, and risk factors. Results were analyzed using the SPSS for Windows, 20.0 (SPSS Inc. - Chicago, Il, United States). Logistic regression was applied to verify variables associated to recurrent wheezing. RESULTS: Among the 1,028 infants studied, 48.5% had one or more episodes of wheezing during the first 12 months of life (wheezing once), and 23.9% had three or more episodes (recurrent wheezing). Nocturnal symptoms, severe breathing difficulty, and visits to the emergency room were observed in 67.3%, 42.4%, and 60.7% of infants, respectively. Among the studied infants, 19.4% were hospitalized, and 11.0% had a medical diagnosis of asthma in the first year of life. Use of β2-agonists, inhaled corticosteroids, oral corticosteroids, and leukotriene receptor antagonists were observed in 88.8%, 21.0%, 54.9%, and 3.2% of children with wheezing, respectively. Use of oral corticosteroids, perception of breathlessness by parents, diagnosis of asthma, pneumonia, and hospitalization for pneumonia were more frequent among infants with recurrent wheezing (p<0.001). CONCLUSIONS: In the city of Santo André, approximately half of infants had at least one episode of wheezing in the first year of life, and almost 25% had recurrent wheezing. Wheezing disorders in Santo André have early onset and high morbidity.