Upper Arm Anthropometry Is Not a Valid Predictor of Regional Body Composition in Preterm Infants

Background: Upper arm anthropometry has been used in the nutritional assessment of small infants, but it has not yet been validated as a predictor of regional body composition in this population. Objective: Validation of measured and derived upper arm anthropometry as a predictor of arm fat and fat-free compartments in preterm infants. Methods: Upper arm anthropometry, including the upper arm cross-sectional areas, was compared individually or in combination with other anthropometric measurements, with the cross-sectional arm areas measured by magnetic resonance imaging, in a cohort of consecutive preterm appropriate-for-gestationalage neonates, just before discharge. Results: Thirty infants born with (mean 8 SD) a gestational age of 30.7 8 1.9 weeks and birth weight of 1,380 8 325 g, were assessed at 35.4 8 1.1 weeks of corrected gestational age, weighing 1,785 8 93 g. None of the anthropometric measurements are reliable predictors (r 2 ! 0.56) of the measurements obtained by magnetic resonance imaging, individually or in combination with other anthropometric measurements. Conclusion: Both measured anthropometry and derived upper arm anthropometry are inaccurate predictors of regional body composition in preterm appropriate-for-gestational-age infants.