Objective: To determine the prevalence of and the risk factors for wheezing in infants under one year of age and residing in the city of Porto Alegre, Brazil. Methods: This was a cross-sectional study and is part of a multicenter, multinational project. The parents or legal guardians of the infants were interviewed at primary health care clinics or during home visits. We used a standardized questionnaire, validated for use in Brazil. Potential risk factors were assessed by means of a Poisson regression model with robust variance estimation, using the Wald test to determine the significance of each variable in the model. Results: The sample comprised 1,013 infants. The majority of those were male (53%), and the mean age was 13.5 ± 1.2 months. In 61% of the infants, there had been at least one episode of wheezing, which had recurred at least three times in one third of those infants. The mean age at the first episode of wheezing was 5.16 months (median, 5 months). Over 40% of the infants with wheezing visited emergency rooms due to wheezing, and 17% of those were hospitalized at least once in the first year of life because of this symptom. In the multivariate analysis, the risk factors for wheezing were as follows: male gender; history of pneumonia; maternal smoking during pregnancy; day care center attendance; low maternal level of education; early weaning; multiple episodes of cold; first viral infection prior to 3 months of age; existence of siblings; and history of asthma in the nuclear family. Conclusions: The prevalence of wheezing is high among infants in the city of Porto Alegre. We identified various risk factors for wheezing in infants.

Keywords: Respiratory sounds/epidemiology; Asthma; Infant; Risk factors.

Objective: The aim of this study was to detect late sequelae of foreign body aspiration in the respiratory tract of children. Methods: This study included children admitted from 1987 to 1999 to Hospital da Criança Santo Antônio, of Porto Alegre, with clinical symptoms of foreign body aspiration to the respiratory tract confirmed by chest X-ray and bronchoscopy. Thirty days after the extraction of the foreign body a perfusion lung scan with technetium was performed. Results: 77% of the foreign bodies were organic materials. In 65% of children the aspiration event occurred at least 7 days before referral. The main location of foreign body was in the right lower lobe bronchus. Perfusion lung scans were performed in 24 patients. In 67% of them reduction in lung perfusion was detected. A chance of sequelae was 3.8 times greater in those patients who had the foreign body removed after 7 days from the aspiration event. Conclusion: This study showed that children that have had foreign body aspiration may have perfusion sequelae in their lungs even after removal of the foreign body. These sequelae were more frequent if the removal was delayed in 7 days of aspiration. Pediatricians must keep this in mind at the follow-up of children that have had foreign body aspiration.

Keywords: foreign bodies; aspiration; bronchi; prognosis