PROPORTIONAL HAZARDS ANALYSIS OF DIARRHEA DUE TO ENTEROTOXIGENIC ESCHERICHIA-COLI AND BREAST-FEEDING IN A COHORT OF URBAN MEXICAN CHILDREN

Ninety-eight women-infant pairs were followed for up to 50 weeks in th e northern part of Guadalajara, Mexico, from August 1986 to July 1987 as part of a community-based, prospective study of the relation betwee n infant feeding patterns and enterotoxigenic Escherichia coli produci ng heat-labile toxin (LT-ETEC) diarrheal disease. Strictly formula-fed children had an incidence of diarrhea over three times that of strict ly breastfed infants and twice that of breast-fed and supplementally f ed children. Strictly formulafed infants colonized by LT-ETEC were sym ptomatic for diarrhea nearly three times as often as strictly breast-f ed infants and twice as often as infants receiving a mixed diet. The f itting of parametric hazard models to durations until LT-ETEC coloniza tion revealed that the hazard for the first colonization was time inva riant. The hazard of diarrhea increased by 400-500% during the rainy s eason or among children 3 months of age or older who received avena, a barley drink. The best-fitting hazard models to durations until sympt omatic expression of LT-ETEC infection all increased through time. Thi s hazard was inversely impacted by the overall amount of LT-ETEC-speci fic, immunoglobulin A antibodies the infant received via the mother's breast milk and by the provision of traditional medicinal teas.