Which Anthropometric Measure Best Correlates with Neonatal Fat Mass at Birth?

Objective Body composition provides additional information than weight alone. There is currently no accepted anthropometric measure of adiposity in infants, yet weight and length data allow calculations of a wide array of indices. The study objective was to identify the anthropometric index which best correlates with neonatal adiposity, by examining the associations between neonatal fat mass and several anthropometric indices of newborn infants. Study Design The sum of skinfolds (SSF), birth weight, and birth length were measured in 94 healthy infants (58% males) born at term to healthy mothers. Several anthropometric indices were calculated, and their relationship with SSF was assessed using linear regression adjusting for gestational age and sex. Results SSF at birth was significantly higher in females compared with males (20.7 ± 3.3 vs. 18.8 ± 4.1 mm, p = 0.019). Birth weight, birth weight-for-gestational-age percentile, birth weight percentile, and weight/length ratio had the highest associations with SSF, yet R ² values were very low, ranging from 16 to 18%. Body mass index (BMI), BMI percentile, ponderal index, and the symmetry index had even lower associations. Conclusion No anthropometric measure can confidently assess fat mass in infants at birth, in accordance with previous research. When body composition data are needed, they should be directly measured.