BREAST-FEEDING, PACIFIER USE AND INFANT DEVELOPMENT AT 12 MONTHS OF AGE - A BIRTH COHORT STUDY IN BRAZIL

Many studies suggest that breast feeding confers developmental and int ellectual advantages on children. In a recent study, however, no assoc iation was found between breast feeding and intelligence in adult life after adjustment for other variables, and the use of pacifier in infa ncy was the most important predictor of intelligence. We analysed the associations between breast-feeding duration, pacifier use and suspect ed developmental delay at 12 months of age in a birth cohort in Pelota s, southern Brazil. All 5304 hospital births occurring during 1993 wer e studied and a sample was followed up at 1, 3, 6 and 12 months of age . Breast-feeding practices and use of pacifiers were assessed at each visit, as well as suspected developmental delay, measured by the Denve r II test. The prevalence of developmental delay was analysed, through logistic regression, according to breast-feeding status and pacifier use, accounting for the possible confounding effect of other variables . The prevalence of suspected developmental delay at 12 months was 34. 1%, being slightly higher among children who used pacifiers at 6 month s than among non-users (35.3% and 28.7% respectively). There was a mar ked negative association between breast-feeding duration and developme ntal delay, with children breast fed for 9 months or more presenting s ignificantly less suspected developmental delay (25.5%) than those bre ast fed for less than 1 month (42.4%). The effects of multiple variabl es were tested, and only high parity, smoking during pregnancy, birthw eight, gestational age, pacifier use and breast-feeding duration remai ned significantly associated with suspected developmental delay. The e ffect of pacifier use, however, disappeared after adjusting for breast -feeding duration, suggesting that breast feeding, and not pacifiers, affects child development.