- This large population-based longitudinal study from Japan looked at behavioral development in children of mothers who breastfed vs those who did not. Results at 2.5
years and 5.5 years of age showed a dose–response association between breastfeeding and age-appropriate developmental behavior skills. In an analysis adjusting for potentially confounding variables, the protective effects of breastfeeding remained.
- Prolonged beneficial effects on behavioral development were associated with breastfeeding.
Breastfeeding and Behavioral Development: A Nationwide Longitudinal Survey in Japan
Takashi Yorifuji, MD, PhD
The Journal of Pediatrics
J Pediatr 2014 Feb 13;[EPub Ahead of Print], T Yorifuji, T Kubo, M Yamakawa, T Kato, S Inoue, A Tokinobu, H Doi
Objective
To prospectively examine the prolonged effect of breastfeeding on behavioral development.
Study design
We used a large, nationwide Japanese population-based longitudinal survey that began in 2001. We restricted participants to term singletons with birth weight >2500 g (n = 41 188). Infant feeding practice was queried at age 6-7 months. Responses to survey questions about age-appropriate behaviors at age 2.5 and 5.5 years were used as indicators of behavioral development. We conducted logistic regression analyses, controlling for potential child and parental confounding factors, with formula feeding as the reference group.
Results
We observed a dose–response relationship between breastfeeding status and an inability to perform age-appropriate behaviors at both ages. With a single exception, all ORs for outcomes for exclusive breastfeeding were smaller than those for partial feeding of various durations. The protective associations did not change after adjustment for an extensive list of confounders or in the sensitivity analyses.
Conclusion
We observed prolonged protective effects of breastfeeding on developmental behavior skills surveyed at age 2.5 and 5.5 years. Beneficial effects were most likely in children who were breastfed exclusively, but whether a biological ingredient in breast milk or extensive interactions through breastfeeding, or both, is beneficial is unclear.