Whole body lean mass at birth significantly tracks to 12 and 36 months of age

Abstract

Childhood is a critical period of musculoskeletal development. Body composition in childhood is predicted by birth weight, but this relationship has not been studied using neonatal body composition in healthy term born infants of appropriate weight for gestational age. The objective of this study was to determine which indices of body composition track best from birth. Twenty‐five children (16 male, 9 female) had weight (wt) and whole body composition measured using dual‐energy x‐ray absorptiometry (Hologic 4500A Discovery Series with infant and pediatric software, Bedford, MA, USA) at 1, 12, and 36 mo of age. Correlation analyses were performed for indices of body composition at 1 mo compared to 12 and 36 mo and significance set at p<0.05. Body wt (g) at 1 mo was related to wt at 12 mo (r=0.61; P<0.001) and 36 mo (r=0.39; P<0.01); wt at 12 mo was also related to wt at 36 mo (r=0.77; P<0.001). Whole body lean mass (LM; g) at 1 mo of age was related to wt (r=0.63; P<0.001) and LM (r=0.51; P<0.01) at 12 mo plus wt (r=0.48; P<0.01) and LM (r=0.50; P<0.001) at 36 mo. At 12 mo, LM related with wt (r=0.63; P<0.05), LM (r=0.73; P<0.001) and % fat (r=−0.50; P<0.05) at 36 mo. Fat mass at 1 mo was not related to subsequent measures, however values at 12 and 36 mo were related (r=0.48; P<0.05). These results suggest lean muscle mass established by 1 mo of age is a consistent indicator of future body composition indices during early development. Funded by CIHR.