Body Composition in Neonates: Relationship Between Measured and Derived Anthropometry with Dual-Energy X-Ray Absorptiometry Measurements

Abstract

This study examined the relationship between measured and derived anthropometric measurements with dual-energy x-ray absorptiometry measured lean and fat mass at 3.0 Ϯ 2.8 (SD) days in 120 neonates with birth weights appropriate (AGA; n ϭ 74), large (LGA; n ϭ 30); or small (SGA, n ϭ 16) for gestational age. Anthropometric measurements, including total body weight and length, and regional measurements, including circumferences of head, chest, abdomen, midarm, and midthigh and dynamic skinfold thickness (15 and 60 s) at tricep, subscapular, suprailiac, and midthigh, were performed. Derived anthropometry included muscle and fat areas, and ratios were calculated from direct measurements. The skinfold thickness measurements between 15 and 60 s were highly correlated (r ϭ 0.973-0.996, p Ͻ 0.001 for all comparisons). Strong correlations existed within the four circumferences of trunk and extremities, the four skinfolds, and the ratios of weight to length and its higher powers. Weight and length accounted for Ͼ97% of the variance of lean mass in AGA and SGA infants and 46% of the variance in LGA infants and for 80, 82, and 84% of the variance of fat mass in SGA, AGA, and LGA infants, respectively, whereas midarm:head circumference ratio and arm muscle and fat areas are the most important derived anthropometry in the prediction for body composition. They independently accounted for up to 16.5 and 10.2%, respectively, of the variance in body composition depending on the state of in utero growth. Thus, total body weight and length and some selected regional and derived anthropometry accounted for the vast majority of the variance of body composition. (Pediatr Res 56: 694-700, 2004) Abbreviations AGA, appropriate for gestational age DXA, dual-energy x-ray absorptiometry LGA, large for gestational age SGA, small for gestational age Weight, length, and head circumference are classic anthropometric measurements to assess growth and nutritional status in the newborn infant. Birth weight is well recognized to have prognostic value for postnatal mortality (1,2), and its use in conjunction with gestation is useful for predicting morbidity (3-6). The simplicity of these measurements and the ease in training an operator to generate highly reproducible results have ensured their use in clinical situations. However, the clinical role of regional anthropometric measurement including circumference and skinfold thickness from various sites on the body and extremities is not well defined. Some reports indicated that regional anthropometry or the ratios and formulas derived from these measurements are good predictors of fetal growth and metabolic disturbances noted in neonates who are over-or undergrown for the duration of gestation (7-9). These refinements of regional anthropometry are thought to reflect more specific body composition, namely lean mass and fat mass (10,11), which allows assessment of the quality of growth such as the extent of energy, fat and protein deposition, and the potential mechanism for disturbed metabolism in infa...

Anthropometry and body composition of south Indian babies at birth

“…This also suggests that the 'thin-fat' paradigm may not apply to the SGA and AGA babies in this group, although the indication (because of the relatively small numbers) is that it may apply to LGA babies. AFI is analogous to percentage body fat and, in studies where both parameters were measured 10 , a comparison of the relationship of AFI or percentage body fat with mean birth weight across gestational groups showed that both increase significantly. Neonatal body composition could track into childhood and adulthood.…”

An observational cohort study of weight- and length-derived anthropometric indicators with body composition at birth and 5 mo: the Healthy Start study

“…Despite a flurry of investigations that used ADP to characterize patterns of fat and lean mass gain during infancy (12)(13)(14), few studies, to our knowledge, have formally assessed the relation between derived anthropometric indexes and directly measured body composition. So far, only a few small cross-sectional analyses of data from both term and preterm infants reported poor correlations of birth weight, as well as weight-and length-based indexes, with neonatal FM (15)(16)(17). To our knowledge, no study to date has evaluated whether or how changes in derived indexes correlate with changes in body composition during infancy.…”

Perinatal consequences of disproportionate fetal trunk growth

“…Our study shows that this disproportion occurs in many macrosomic as well as normal-weight babies, whether or not their mother had glucose intolerance. Macrosomic neonates usually have a head and chest of equal size [15,16], or have a head substantially smaller than the chest [16], the opposite of what is observed in most normal birth weight babies [2,3]. Our sample size was inadequate to assess the difference in the frequency of Erb palsy, or even shoulder dystocia between cases and controls, because the prevalence of both is low (about 20/1000 for shoulder dystocia and 2.5/1000 for brachial plexus injury).…”