Acute lower respiratory illness in under-five children in Rio Grande, Rio Grande do Sul State, Brazil: prevalence and risk factors.

This study aimed to determine the prevalence of acute lower respiratory illness and to identify associated factors among children less than five years of age in the city of Rio Grande, southern Brazil. Using a cross-sectional survey, a standardized household questionnaire was applied to mothers or guardians. Information was collected on household conditions, socioeconomic status, and parental smoking. Prenatal care attendance, nutritional status, breastfeeding pattern, and use of health services for the children were also investigated. Data analysis was based on prevalence ratios and logistic regression, using a conceptual framework. Among 771 children studied, 23.9% presented acute lower respiratory illness. The main risk factors were previous episodes of acute lower respiratory infection or wheezing, crowding, maternal schooling less than five years, monthly family income less than US$ 200, four or more people per room, asthma in family members, and maternal smoking. Mothers 30 years or older were identified as a protective factor. These results can help define specific measures to reduce morbidity and mortality due to acute lower respiratory illness in this setting.