Background/Objectives: Birth weight (BW), independent of socioeconomic status, has been identified as a predictor for childhood cognitive development. However, it is not known whether this relation is related to low BW per se or particularly related to a deficit in fat mass (FM) or fat-free mass (FFM) at birth. This study therefore aimed at investigating the relation between body composition at birth and child development at 2 years of age.

Subjects/Methods: An Ethiopian birth cohort was followed up at 2 years. Body composition was measured within 48 h of birth using infant air-displacement plethysmography. Child development was assessed at 2 years of age using Denver developmental screening test. Associations between body composition at birth and development at 2 years of age were tested using linear regression analysis.

Results: FFM but not FM at birth was positively associated with higher global developmental score at 2 years of age (β=2.48, 95% confidence interval (CI) 0.17; 4.79) adjusted for neonatal, postnatal and parental characteristics. This association was attributable to the association with the language developmental domain (β=1.61, 95 CI 0.33; 2.90).

Conclusions: Among Ethiopian children, FFM at birth but not FM predicted better global and language development at 2 years of age. Higher FFM at birth might have exerted a positive effect on the growth and differentiation of the brain and neuronal circuits for better development. This study therefore highlights the need to improve mother's nutritional status during pregnancy in ways that stimulate fetal FFM growth.European Journal of Clinical Nutrition advance online publication, 27 September 2017; doi:10.1038/ejcn.2017.129.