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.

The intellectual development, mental and behavioural disorders in children from Belarus exposed in utero following the chernobyl accident

The study examined psychological development in 250 children at the age of 6-7 and 10-12 years who had been exposed in the prenatal period at the time of the Chernobyl accident in 1986. These children were compared to a control group of 250 children of the same age from non- and slightly contaminated areas of Belarus. The examination included psychiatric examination and intellectual assessment as well as the estimation of thyroid exposure in utero. The mean value of thyroid doses from (131)I 0.39 Gy was estimated for the prenatal exposed children. The children of the exposed group had a lower mean full-scale IQ compared to the control group (89.6 +/- 10.2 vs 92.1 +/- 10.5 at the age of 6-7 years, P = 0.007; and 94. 3 +/- 10.4 vs 95.8 +/- 10.9 at the age of 10-12 years, P = 0.117). Average IQ for the subgroup of highly exposed children (thyroid doses more than 1 Gy) was lower in comparison with average IQ for the whole exposed group (85.7 +/- 6.4 vs 89.6 +/- 10.2 at the age of 6-7 years, P = 0.014; 89.1 +/- 7.1 vs 94.3 +/- 10.4 at age 10-12 years, P = 0.003). No statistically significant distinctions in average IQ were found between the different subgroups of children in relation to the gestational age at the time of the Chernobyl accident. We notice a positive moderate correlation between IQ of children and the educational level of their parents (in exposed group - mothers: r = 0.50, P < 0.01 and fathers: r = 0.52, P < 0.01; in control group - mothers: r = 0.41, P < 0.05 and fathers: r = 0.42, P < 0.05). There was a moderate correlation between high personal anxiety in parents and emotional disorders in children (for mothers r = 0.38, P < 0.05; for fathers r = 0.43, P < 0.01). The relative risk of mental and behavioural disorders has been estimated for emotional disorders OR = 2.67, P < 0.001. The frequency of the formation of mental retardation, hyperkinetic disorders and other mental and behavioural disorders in children from both groups was approximately the same. We conclude that in the genesis of borderline intellectual functioning and emotional disorders in the exposed group of children a significant role was probably played by unfavourable social-psychological and sociocultural factors such as a low educational level of the parents, the break of microsocial contacts and difficulties adapting, which appeared following the evacuation and relocation from the contaminated areas.

The psychological development of children from Belarus exposed in the prenatal period to radiation from the Chernobyl atomic power plant

This study examined psychological development in 138 children at the age of 6-7 and 10-11 years, who had suffered prenatal radiation exposure at the time of the Chernobyl accident in 1986. These children were compared to a control group of 122 children of the same age from noncontaminated areas of Belarus. The examination included neurological and psychiatric examination, intellectual assessment, and clinical psychological investigation of parents as well as the estimation of thyroid exposure in utero. The exposed group manifested a relative increase in psychological impairment compared with the control group, with increased prevalence in cases of specific developmental speech-language disorders (18.1% vs. 8.2% at 6-7 years; 10.1% vs. 3.3% at 10-11 years) and emotional disorders (20.3% vs. 7.4% at 6-7 years; 18.1 vs. 7.4% at 10-11 years). The mean IQ of the exposed group was lower than that of the control group, and there were more cases of borderline IQ (IQ = 70-79) (15.9% vs. 5.7% at 6-7 years; and 10.1% vs. 3.3% at 10-11 years). The mean value of thyroid doses from 131I 0.4 Gy was estimated for children exposed in utero. No correlation was found between individual thyroid doses and IQ at age 6-7 years or 10-11 years. We notice a positive moderate correlation between IQ of children and the educational level of their parents. There was a moderate correlation between high personal anxiety in parents and emotional disorders in children. We conclude that a significant role in the genesis of borderline intellectual functioning, specific developmental disorders of speech, language and scholastic skills, as well as emotional disorders in the exposed group of children was played by unfavourable social-psychological and social-cultural factors such as a low educational level of parents, the break of microsocial contacts, and adaptational difficulties, which appear following the evacuation and relocation from the contaminated areas.