“…The most obvious difference lies in the sample sizes employed; while we analyzed nearly 8,000 children, the studies of Ou et al, 9 Solis-Urra et al, 10 and Koshiyama et al 11 included substantially smaller numbers of participants (42, 92, and 207, respectively), which might have limited their power to identify the brain regions that we report here. Second, Ou et al 9 compared brain differences between breastfed children and those fed with milk formula, and Solis-Urra et al 10 and Koshiyama et al 11 employed a categorical variable for breastfeeding duration, while we assessed the effects of breastfeeding duration with a continuous measure. Lastly, other differences, such as the covariates included in the analyses, the population studied, and how data were acquired, could also partially account for these discrepancies.…”