RESUMEN
OBJECTIVE: To assess the association between breastfeeding and child cognitive development in term and preterm children. STUDY DESIGN: We analyzed data on white singleton children from the United Kingdom Millennium Cohort Study. Children were grouped according to breastfeeding duration. Results were stratified by gestational age at birth: 37 to 42 weeks (term, n = 11,101), and 28 to 36 weeks (preterm, n = 778). British Ability Scales tests were administered at age 5 years (naming vocabulary, pattern construction, and picture similarities subscales). RESULTS: The mean scores for all subscales increased with breastfeeding duration. After adjusting for confounders, there was a significant difference in mean score between children who were breastfed and children who were never breastfed: in term children, a two-point increase in score for picture similarities (when breastfed ≥ 4 months) and naming vocabulary (when breastfed ≥ 6 months); in preterm children, a 4-point increase for naming vocabulary (when breastfed ≥ 4 months) and picture similarities (when breastfed ≥ 2 months) and a 6-point increase for pattern construction (when breastfed ≥ 2 months). These differences suggest that breastfed children will be 1 to 6 months ahead of children who were never breastfed. CONCLUSIONS: In white, singleton children in the United Kingdom, breastfeeding is associated with improved cognitive development, particularly in children born preterm.