title: The effect of breastfeeding on child development at 5 years: a cohort study.
abstract: OBJECTIVE
  It is uncertain to what degree the relationship between breastfeeding and later cognitive development is a true biological effect, or is confounded by psychosocial factors. The study aim was to further investigate this relationship and the effect of duration of breast feeding on cognitive development.
  
  
  METHODS
  A total of 3880 children were followed from birth. Breastfeeding duration was measured by questionnaire at 6 months of age and a Peabody Picture Vocabulary Test Revised (PPVT-R) was administered at 5 years. PPVT-R scores were adjusted for the effects of a large array of biological and psychosocial confounders. The relationship between breastfeeding and the mean PPVT-R scores were examined using analysis of variance and multiple linear regression.
  
  
  RESULTS
  A strong positive relationship was demonstrated between breastfeeding and the PPVT-R scores with increasing scores with increased duration of breastfeeding. After adjusting for a wide range of biological and social factors, the adjusted mean for those breastfed for 6 months or more was 8.2 points higher for females and 5.8 points for males when compared to those never breastfed.
  
  
  CONCLUSIONS
  These findings suggest a significant benefit to child development is conferred by breastfeeding and is related independently to longer periods of breastfeeding.
authors.affiliation: Child Development and, Rehabilitation Services, Mater Children's Hospital, South Brisbane, Queensland, Australia.
authors.forename: P J
authors.initials: PJ
authors.lastname: Quinn
authors.forename: M
authors.initials: M
authors.lastname: O'Callaghan
authors.forename: G M
authors.initials: GM
authors.lastname: Williams
authors.forename: J M
authors.initials: JM
authors.lastname: Najman
authors.forename: M J
authors.initials: MJ
authors.lastname: Andersen
authors.forename: W
authors.initials: W
authors.lastname: Bor
mesh_terms: D000328:Adult; D001942:Breast Feeding / Q000523:psychology* / Q000706:statistics & numerical data*; D002657:Child Development; D002675:Child, Preschool; D015331:Cohort Studies; D004522:Educational Status; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007361:Intelligence Tests; D008297:Male; D017533:Marital Status; D008423:Maternal Age; D009035:Mothers / Q000706:statistics & numerical data*; D011793:Queensland; D011795:Surveys and Questionnaires; D013997:Time Factors