The Effects of Breastfeeding on Childhood Behavioral and Emotional Development: A Prospective Cohort Study in China

Background: Breastfeeding could improve a child’s health early on, but its long-term effects on childhood behavioral and emotional development remain inconclusive. We aimed to estimate the associations of feeding practice with childhood behavioral and emotional development. Methods: In this population-based birth cohort study, data on feeding patterns for the first 6 mo of life, the duration of breastfeeding, and children’s emotional and behavioral outcomes were prospectively collected from 2489 mother–child dyads. Feeding patterns for the first 6 mo included exclusive breastfeeding (EBF) and non-exclusive breastfeeding (non-EBF, including mixed feeding or formula feeding), and the duration of breastfeeding (EBF or mixed feeding) was categorized into ≤6 mo, 7–12 mo, 13–18 mo, and >18 mo. Externalizing problems and internalizing problems were assessed with the Child Behavior Checklist (CBCL) and operationalized according to recommended clinical cutoffs, corresponding to T scores ≥64. Multivariable linear regression and logistic regression were used to evaluate the association of feeding practice with CBCL outcomes. Results: The median (interquartile range) age of children at the outcome measurement was 32.0 (17.0) mo. Compared with non-EBF for the first 6 mo, EBF was associated with a lower T score of internalizing problems adjusted mean difference (aMD): −1.31; 95% confidence interval (95% CI): −2.53, −0.10, and it was marginally associated with T scores of externalizing problems (aMD: −0.88; 95% CI: −1.92, 0.15). When dichotomized, EBF versus non-EBF was associated with a lower risk of externalizing problems (aOR: 0.54, 95% CI: 0.34, 0.87), and it was marginally associated with internalizing problems (aOR: 0.75, 95% CI: 0.54, 1.06). Regarding the duration of breastfeeding, breastfeeding for 13–18 mo versus ≤6 mo was associated with lower T scores of internalizing problems (aMD: −2.50; 95% CI: −4.43, −0.56) and externalizing problems (aMD: −2.75; 95% CI: −4.40, −1.10), and breastfeeding for >18 mo versus ≤6 mo was associated with lower T scores of externalizing problems (aMD: −1.88; 95% CI: −3.68, −0.08). When dichotomized, breastfeeding for periods of 7–12 mo, 13–18 mo, and >18 mo was associated with lower risks of externalizing problems aOR (95% CI): 0.96 (0.92, 0.99), 0.94 (0.91, 0.98), 0.96 (0.92, 0.99), respectively. Conclusions: Exclusive breastfeeding for the first 6 mo and a longer duration of breastfeeding, exclusively or partially, are beneficial for childhood behavioral and emotional development.