Impact of breast feeding on admission for pneumonia during postneonatal period in Brazil: nested case-control study

Objective To determine whether breast feeding protects infants against pneu monia and whether the protection varies with age. Design Nested case-control study. Setting Pelotas, southern Brazil. Subjects Cases were 152 infants aged 28-364 days who had been admitted to h ospital for pneumonia. Controls were 2391 cases in a population based case- control study Main outcome measure Odds ratio of admission for pneumonia according to typ e of milk consumed (breast milk alone, breast and formula milk, or formula milk and other fluids only), use of fluid supplements apart from formula mi lk, and use of solid supplements. Results Infants who were not being breast fed were 17 times more likely tha n those being breast fed without formula milli to be admitted to hospital f or pneumonia (95% confidence interval 7.7 to 36.0). This relative risk was 61 (19.0 to 195.5) for children under 3 months old, decreasing to 10 (2.8 t o 36.2) thereafter. Supplementation with solids was associated with a relat ive risk of 13.4 (7.6 to 23.5) for all infants and 175 (21.8 to 1405.1) for those under 3 months old. Conclusion Breast feeding protects young children against pneumonia, especi ally in the first months of life. These results may be used for targeting i ntervention campaigns at the most vulnerable age groups.