Do children exclusively breastfed for 3 months or 6 months differ in health and development at age 6.5 years?

The Australian Dietary Guidelines for Children and Adolescents (1) in line with the World Health Organisation, recommend that infants be exclusively breastfed for the first 6 months of life. Despite this recommendation,  indications are that few mothers exclusively breastfeed for this length of time. A recent study has compared the health and development outcomes of children at age 6.5 years, who were either exclusively breastfed for 3 months or 6 months (2).

The study was part of the Promotion of Breastfeeding Intervention Trial (PROBIT) which took place in the Republic of Belarus. Healthy term infants were included in the trial and were followed up during clinic visits at age 1,2,3,4,6,9 and 12 months. Infants were divided into 2 groups:--1.those exclusively breast fed for  6 months (BF6) who received no food or drink other than breast milk and 2. those exclusively breastfed for 3 months but who continued to be breastfed partially for 6 or more months (EB3). The infants were followed up at 6.5 years by their clinic paediatrician who conducted anthropometric measures, allergy testing, blood pressure measurements and cognitive testing. Teachers and parents were also asked to complete a Strength and Difficulties Questionnaire which measured if the child had conduct problems, hyperactivity, was emotionally stable, and had peer problems.

2427 children BF3 (84.7% of the original sample) and 524 children BF6 (89.4% of original sample) were seen at 6.5 years. There was little diiference at 6.5 years between the groups with the significant differences being that those in the BF6 group had a higher BMI, triceps skinfold thickness and hip circumference. There were no significant differences in cognitive or academic function.  It needs to be noted that the numbers in the BF6 group were small compared to the BF3 group and that those BF3 were still benefiting from partial breast feeding.

The authors conclude that there are no long term noticeable benefits or adverse effects from exclusively breast feeding for 6 months. The benefits of breast feeding to the mother and infant appear to apply whilst exclusively breast feeding rather than having a long term effect.

References.

1. NH&MRC. Dietary Guidelines for Children and Adolescents. Commonwealth of Australia 2003.

2. Kramer MS, Matush L, Bogdanovich N et al. Health and development outcomes in 6.5-y-old children breastfed exclusively for 3 or 6 months. Am J Clin Nutr 2009;90:1070-4