title: Breastfeeding and child cognitive development: new evidence from a large randomized trial.
abstract: BACKGROUND
  The evidence that breastfeeding improves cognitive development is based almost entirely on observational studies and is thus prone to confounding by subtle behavioral differences in the breastfeeding mother's behavior or her interaction with the infant.
  
  
  OBJECTIVE
  To assess whether prolonged and exclusive breastfeeding improves children's cognitive ability at age 6.5 years.
  
  
  METHODS
  Cluster-randomized trial, with enrollment from June 17, 1996, to December 31, 1997, and follow-up from December 21, 2002, to April 27, 2005.
  
  
  METHODS
  Thirty-one Belarussian maternity hospitals and their affiliated polyclinics.
  
  
  METHODS
  A total of 17,046 healthy breastfeeding infants were enrolled, of whom 13,889 (81.5%) were followed up at age 6.5 years.
  
  
  METHODS
  Breastfeeding promotion intervention modeled on the Baby-Friendly Hospital Initiative by the World Health Organization and UNICEF.
  
  
  METHODS
  Subtest and IQ scores on the Wechsler Abbreviated Scales of Intelligence, and teacher evaluations of academic performance in reading, writing, mathematics, and other subjects.
  
  
  RESULTS
  The experimental intervention led to a large increase in exclusive breastfeeding at age 3 months (43.3% for the experimental group vs 6.4% for the control group; P < .001) and a significantly higher prevalence of any breastfeeding at all ages up to and including 12 months. The experimental group had higher means on all of the Wechsler Abbreviated Scales of Intelligence measures, with cluster-adjusted mean differences (95% confidence intervals) of +7.5 (+0.8 to +14.3) for verbal IQ, +2.9 (-3.3 to +9.1) for performance IQ, and +5.9 (-1.0 to +12.8) for full-scale IQ. Teachers' academic ratings were significantly higher in the experimental group for both reading and writing.
  
  
  CONCLUSIONS
  These results, based on the largest randomized trial ever conducted in the area of human lactation, provide strong evidence that prolonged and exclusive breastfeeding improves children's cognitive development.
  
  
  BACKGROUND
  isrctn.org Identifier: ISRCTN37687716.
authors.affiliation: Department of Pediatrics, McGill University, Montreal, Quebec, Canada. michael.kramer@mcgill.ca
authors.forename: Michael S
authors.initials: MS
authors.lastname: Kramer
authors.forename: Frances
authors.initials: F
authors.lastname: Aboud
authors.forename: Elena
authors.initials: E
authors.lastname: Mironova
authors.forename: Irina
authors.initials: I
authors.lastname: Vanilovich
authors.forename: Robert W
authors.initials: RW
authors.lastname: Platt
authors.forename: Lidia
authors.initials: L
authors.lastname: Matush
authors.forename: Sergei
authors.initials: S
authors.lastname: Igumnov
authors.forename: Eric
authors.initials: E
authors.lastname: Fombonne
authors.forename: Natalia
authors.initials: N
authors.lastname: Bogdanovich
authors.forename: Thierry
authors.initials: T
authors.lastname: Ducruet
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Collet
authors.forename: Beverley
authors.initials: B
authors.lastname: Chalmers
authors.forename: Ellen
authors.initials: E
authors.lastname: Hodnett
authors.forename: Sergei
authors.initials: S
authors.lastname: Davidovsky
authors.forename: Oleg
authors.initials: O
authors.lastname: Skugarevsky
authors.forename: Oleg
authors.initials: O
authors.lastname: Trofimovich
authors.forename: Ludmila
authors.initials: L
authors.lastname: Kozlova
authors.forename: Stanley
authors.initials: S
authors.lastname: Shapiro
mesh_terms: D000367:Age Factors; D001942:Breast Feeding / Q000706:statistics & numerical data*; D002648:Child; D002657:Child Development / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D015995:Prevalence