Health and development outcomes in 6.5-y-old children breastfed exclusively for 3 or 6 mo.

BACKGROUND: Despite the current World Health Organization recommendation that infants be exclusively breastfed for 6 mo, this practice remains unusual in both developed and developing countries. OBJECTIVE: The objective was to compare health and development outcomes at age 6.5 y in children who were exclusively breastfed for 3 mo (EBF3) or for 6 mo (EBF6); in the EBF3 group, the children continued partial breastfeeding for > or =6 mo. DESIGN: This was a prospective cohort study nested within a large, cluster-randomized trial of a breastfeeding promotion intervention in the Republic of Belarus. Outcomes compared at 6.5 y included anthropometric measurements, systolic and diastolic blood pressure, intelligence quotient, teachers' ratings of academic performance, parent- and teacher-rated behavior, atopic symptoms, allergen skin-prick tests, and dental caries. All statistical analyses were adjusted for cluster- and individual-level covariates and for clustering of outcomes within the clinics at which the children were examined. RESULTS: The 2427 EBF3 and 524 EBF6 children who were followed up represented 84.7% and 89.4%, respectively, of those followed for the first year of life. The only significant differences observed between the 2 groups were in mean body mass index, triceps skinfold thickness, and hip circumference, all of which were higher in the EBF6 group. CONCLUSIONS: We observed no demonstrable beneficial or adverse long-term effects on child health of exclusive breastfeeding for 6 mo. Higher adiposity measures in the EBF6 group probably reflect reverse causality rather than a causal effect of prolonged exclusive breastfeeding. Established benefits appear to be limited to the period of exclusive breastfeeding.

Breastfeeding and child cognitive development: new evidence from a large randomized trial.

CONTEXT: 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. DESIGN: Cluster-randomized trial, with enrollment from June 17, 1996, to December 31, 1997, and follow-up from December 21, 2002, to April 27, 2005. SETTING: Thirty-one Belarussian maternity hospitals and their affiliated polyclinics. PARTICIPANTS: A total of 17,046 healthy breastfeeding infants were enrolled, of whom 13,889 (81.5%) were followed up at age 6.5 years. INTERVENTION: Breastfeeding promotion intervention modeled on the Baby-Friendly Hospital Initiative by the World Health Organization and UNICEF. MAIN OUTCOME MEASURES: 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. CONCLUSION: 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. TRIAL REGISTRATION: isrctn.org Identifier: ISRCTN37687716.

Effects of prolonged and exclusive breastfeeding on child behavior and maternal adjustment: evidence from a large, randomized trial.

OBJECTIVE: The objective of this study was to assess the long-term effects of breastfeeding on child behavior and maternal adjustment. METHODS: We followed up children who were in the Promotion of Breastfeeding Intervention Trial, a cluster-randomized trial of a breastfeeding promotion intervention based on the World Health Organization/United Nations Children's Fund Baby-Friendly Hospital Initiative. A total of 17,046 healthy, breastfeeding mother-infant pairs were enrolled from 31 Belarussian maternity hospitals and affiliated polyclinics; 13,889 (81.5%) were followed up at 6.5 years. Mothers and teachers completed the Strengths and Difficulties Questionnaire and supplemental questions bearing on internalizing and externalizing behavioral problems. Mothers also responded to questions concerning their relationships to their partner and child and their breastfeeding of subsequently born children. RESULTS: The experimental intervention led to a large increase in exclusive breastfeeding at 3 months (43.3% vs 6.4%) and a significantly higher prevalence of any breastfeeding at all ages up to and including 12 months. No significant treatment effects were observed on either the mother or the teacher Strengths and Difficulties Questionnaire ratings of total difficulties, emotional symptoms, conduct problems, hyperactivity, peer problems, or prosocial behavior or on the supplemental behavioral questions. We found no evidence of treatment effects on the parent's marriage or on the mother's satisfaction with her relationships with her partner or child, but the experimental intervention significantly increased the duration of any breastfeeding, and mothers in the experimental group were nearly twice as likely to breastfeed exclusively the next-born child for at least 3 months. CONCLUSIONS: On the basis of the largest randomized trial ever conducted in the area of human lactation, we found no evidence of risks or benefits of prolonged and exclusive breastfeeding for child and maternal behavior. Breastfeeding promotion does, however, favorably affect breastfeeding of the subsequent child.