Duration of breast-feeding and Bayley's Mental Developmental Index at 1 year of age

Objective: To examine the association between duration of exclusive breast- feeding and developmental indices in initially breast-fed infants at 1 year of age. Methodology: A cohort of 96 healthy term infants, aged between 10 and 14 mo nths, were recruited from public immunization clinics and child care centre s in southern metropolitan Adelaide. infants were assessed using the Bayley Scales of Infant Development (Mental and Psychomotor Developmental Indices ) within 2 weeks of enrolment, Information regarding duration of breast-fee ding was provided retrospectively by the mothers of the infants. Duration o f exclusive breast-feeding and sociodemographic variables were used as inde pendent variables to determine their effects an development. Results: Due to a significant interaction between duration of breast-feedin g and gender on mental development scores, separate regression models for b oys and girls were explored. Duration of breast-feeding significantly predi cted mental development scores for boys (partial r(2) = 0.14, P < 0.005), b ut not for girls. Duration of breast-feeding did not predict psychomotor de velopment scores. Conclusions: These findings deserve further examination in large, prospecti ve studies.