Associations Between Duration of Breast Feeding and Neurocognitive Development of the Offspring

There is considerable evidence that breast feeding has a beneficial effect on neurocognition of the child. However, most studies have confined their attention to the IQ of the offspring rather than other aspects of neurodevelopment. Here we have compared children who were breast fed for at least six months with children who have never been breast fed concerning 373 different neurocognitive outcomes measured from infancy to late adolescence using data collected by the Avon Longitudinal Study of Parents and Children (ALSPAC). We first examined unadjusted regression associations and selected 152 of the 373 variables where the P-value for comparison between the two groups was < 0.0001. These 152 outcomes were then adjusted for seven social and other factors, revealing 42 outcomes with adjusted associations at P< 0.001: specifically, these included associations with full-scale IQ at ages 8 and 15 years (adjusted mean difference (MD), [95% confidence interval (CI)] were +4.11[95%CI 2.83, 5.39] and +5.12 [95%CI 3.57, 6.67] IQ points respectively. As well as the components of IQ, the other phenotypes that were strongly related to having been breast fed for 6 months were measures of academic ability including reading, use of the English language and mathematics. In line with the literature, we show that children who were breast fed are more likely to be right-handed. We conclude that breast feeding for at least 6 months has beneficial effects on a number of neurocognitive outcomes that are likely to play a major part in the offspring’s future life choices. We point out, however, that this study has not yet considered other potential long-term biological benefits of breast feeding.