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Background: Currently available infant body composition measurement methods are impractical for routine clinical use. The study developed anthropometric equations (AEs) to estimate fat mass (FM, kg) during the first year using air displacement plethysmography (PEA POD® Infant Body Composition System) and Infant quantitative magnetic resonance (Infant-QMR) as criterion methods., Methods: Multi-ethnic full-term infants (n = 191) were measured at 3 days, 15 and 54 weeks. Sex, race/ethnicity, gestational age, age (days), weight-kg (W), length-cm (L), head circumferences-cm (HC), skinfold thicknesses mm [triceps (TRI), thigh (THI), subscapular (SCP), and iliac (IL)], and FM by PEA POD® and Infant-QMR were collected. Stepwise linear regression determined the model that best predicted FM., Results: Weight, length, head circumference, and skinfolds of triceps, thigh, and subscapular, but not iliac, significantly predicted FM throughout infancy in both the Infant-QMR and PEA POD models. Sex had an interaction effect at 3 days and 15 weeks for both the models. The coefficient of determination [R 2 ] and root mean square error were 0.87 (66 g) at 3 days, 0.92 (153 g) at 15 weeks, and 0.82 (278 g) at 54 weeks for the Infant-QMR models; 0.77 (80 g) at 3 days and 0.82 (195 g) at 15 weeks for the PEA POD models respectively., Conclusions: Both PEA POD and Infant-QMR derived models predict FM using skinfolds, weight, head circumference, and length with acceptable R 2 and residual patterns., (© 2021 World Obesity Federation.)

Objective: The precision and accuracy of a quantitative magnetic resonance (EchoMRI Infants) system in newborns were determined., Methods: Canola oil and drinking water phantoms (increments of 10 g to 1.9 kg) were scanned four times. Instrument reproducibility was assessed from three scans (within 10 minutes) in 42 healthy term newborns (12-70 hours post birth). Instrument precision was determined from the coefficient of variation (CV) of repeated scans for total water, lean mass, and fat measures for newborns and the mean difference between weight and measurement for phantoms. In newborns, the system accuracy for total body water (TBW) was tested against deuterium dilution (D 2 O)., Results: In phantoms, the repeatability and accuracy of fat and water measurements increased as the weight of oil and water increased. TBW was overestimated in amounts >200 g. In newborns weighing 3.14 kg, fat, lean mass, and TBW were 0.52 kg (16.48%), 2.28 kg, and 2.40 kg, respectively. EchoMRI's reproducibility (CV) was 3.27%, 1.83%, and 1.34% for total body fat, lean mass, and TBW, respectively. EchoMRI-TBW values did not differ from D 2 O; mean difference, -1.95 ± 6.76%, P = 0.387; mean bias (limits of agreement), 0.046 kg (-0.30 to 0.39 kg)., Conclusions: The EchoMRI Infants system's precision and accuracy for total body fat and lean mass are better than established techniques and equivalent to D 2 O for TBW in phantoms and newborns., (© 2017 The Obesity Society.)

Fetal body composition is an important determinant of body composition at birth, and it is likely to be an important determinant at later stages in life. The purpose of this work is to provide a comprehensive overview by presenting data from previously published studies that report on body composition during fetal development in newborns and the infant/child through 5 years of age. Understanding the changes in body composition that occur both in utero and during infancy and childhood, and how they may be related, may help inform evidence-based practice during pregnancy and childhood. We describe body composition measurement techniques from the in utero period to 5 years of age, and identify gaps in knowledge to direct future research efforts. Available literature on chemical and cadaver analyses of fetal studies during gestation is presented to show the timing and accretion rates of adipose and lean tissues. Quantitative and qualitative aspects of fetal lean and fat mass accretion could be especially useful in the clinical setting for diagnostic purposes. The practicality of different pediatric body composition measurement methods in the clinical setting is discussed by presenting the assumptions and limitations associated with each method that may assist the clinician in characterizing the health and nutritional status of the fetus, infant and child. It is our hope that this review will help guide future research efforts directed at increasing the understanding of how body composition in early development may be associated with chronic diseases in later life.

Summary: Background: Ethnic differences in total body fat (fat mass [FM]) have been reported in adults and children, but the timing of when these differences manifest and whether they are present at birth are unknown. Objectives: This study aimed to assess whether ethnic differences in body fat are present at birth in healthy infants born at term, where body fat is measured using air displacement plethysmography and fat distribution by skin‐fold thickness. Methods: Data were from a multiracial cross‐sectional convenience sample of 332 term infants from four racial or ethnic groups based on maternal self‐report (A, Asian; AA, non‐Hispanic Black [African‐American]; C, non‐Hispanic White; and H, Hispanic). The main outcome measure was infant body fat at 1–3 days after birth, with age, birth weight, gestational age and maternal pre‐pregnancy weight as covariates. Results: Significant effects for race (P = 0.0011), sex (P = 0.0051) and a race by sex interaction (P = 0.0236) were found. C females had higher FM than C males (P = 0.0001), and AA females had higher FM than AA males (P = 0.0205). C males had less FM than A males (P = 0.0353) and H males (P = 0.0001). Conclusion: Race/ethnic and sex differences in FM are present in healthy term newborns. Although the implications of these differences are unclear, studies beginning in utero and birth set the stage for a life course approach to understanding disease later in life. [ABSTRACT FROM AUTHOR]