Risk factors for deaths due to respiratory infections among Brazilian infants.

In a population based case-control study, 127 Brazilian infants who died due to a respiratory infection were compared with 254 neighbourhood controls. The main risk factors associated with mortality were low socioeconomic status (including low levels of parental education) and--after adjustment for socioeconomic status--lack of breastfeeding, lack of supplementation with non-milk foods, crowding, the number of under-fives in the family, lack of a flush toilet, low birthweight, low weight-for-age and having a young mother. In a multivariate analysis, the variables found to be most closely associated with mortality were breastfeeding, education of the father, the number of under-fives, family income and birthweight. Having a low weight-for-age was also strongly associated with mortality but the retrospective nature of the study makes this finding difficult to interpret.