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

Abstract

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-gestational-age neonates, just before discharge. Results: Thirty infants born with (mean ± SD) a gestational age of 30.7 ± 1.9 weeks and birth weight of 1,380 ± 325 g, were assessed at 35.4 ± 1.1 weeks of corrected gestational age, weighing 1,785 ± 93 g. None of the anthropometric measurements are reliable predictors (r² < 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.

Nutritional Assessment in Preterm Infants: A Practical Approach in the NICU

“…Measurements are taken with the arm extended, at mid distance between the tip of the acromion and the olecraneon with the infant in dorsal decubitus and the arm lying laterally to the trunk [16,58]. In extremely premature infants, accurate MUAC measurement may be difficult due to inadvertent compression of the skin and underlying loose tissues when attempting to adjust the tape perfectly around the arm, or by small spaces left between the wrinkled skins when avoiding compression [59].…”

“…In full-term infants, a poor correlation of arm areas with ultrasound measurements was found, leading to overestimation of muscle and underestimation of fat [79]. In preterm infants, arm muscle and fat areas were inaccurate predictors ( r 2 < 0.56) of magnetic resonance imaging measurements [59]. These poor correlations may be explained by the limited reliability of MUAC [57] and triceps skinfold [65] measurements and by the oversimplification of geometrical assumptions used for the calculation of cross-sectional arm areas [16].…”

Adjustability and Adaptability Are Critical Characteristics of Pediatric Support Surfaces

“…The proportions, dimensions, and mechanical properties of the tissues were all adopted from the literature. [22][23][24] Then, we positioned a 2-mm rigid tube under the arm between the subcutaneous fat layer and either a flat foam mattress with stiffness (elastic modulus) of 25 kPa or an air-cell-based (ACB) mattress, modeled similarly to the flat foam cushion and the ACB cushion in our previous work. 25 To simulate the worst-case scenario, we positioned the tube on the top of the air cell (as opposed to in the groove between adjacent air cells).…”

Effect of different composition of human milk and its fortification in body composition and neurodevelopment in a cohort of very preterm infants

“…(105) Recently, validated reference sex-specific curves were published to track changes in BMI for prematurely born infants. (106) However, in newborn infants, BMI was found to be poor a predictor of adiposity, Studies validating upper arm cross-sectional areas in term (113) and preterm (114) infants using imaging methods questioned their accuracy in predicting arm fat and muscle.…”