Impact estimates of breastfeeding over infant mortality

Infant mortality in the state of São Paulo has decreased in the last years and it seems to be leveling off at a limit beyond which further reductions are challenging. Early neonatal causes account for 50% of these deaths and the remaining are mostly due to pneumonia and diarrhea. This study is to assess the impact of breastfeeding over death reduction. Fourteen municipalities of greater São Paulo were studied. Data on breastfeeding was collected through surveys conducted on national immunization campaign days and mortality data was taken from 1999 and 2000 official records. Drawing from literature parameters on risk for death from respiratory infection and diarrhea in non-breastfed infants, fractions of mortality preventable by breastfeeding were calculated. These figures applied to the number of recorded deaths allowed assessing the impact of breastfeeding over mortality for each municipality. Fractions of respiratory infection mortality preventable by breastfeeding varied according to locality and age group between 33% and 72%. As to diarrhea, variation was between 35% and 86%. The impact of breastfeeding over infant mortality was an average reduction of 9.3% with values raging from 3.6% to 13%, depending on the locality considered. Breastfeeding in the first year of life might be the most feasible strategy to further reduce the current levels of infant mortality in the state of São Paulo.