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The effect of breastfeeding on child development at 5 years: A cohort study


Correspondence: M O'Callaghan Director, Child Development and, Rehabilitation Services, Mater Children’s Hospital, Raymond Terrace, South Brisbane 4101, Australia. Fax: + 61 7 3840 1744; email:


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 questionaire 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.

Conclusion: These findings suggest a significant benefit to child development is conferred by breastfeeding and is related independently to longer periods of breastfeeding.