Prediction of fat-free mass and percentage of body fat in neonates using bioelectrical impedance analysis and anthropometric measures: validation against the PEA POD

Abstract

Accurate assessment of neonatal body composition is essential to studies investigating neonatal nutrition or developmental origins of obesity. Bioelectrical impedance analysis or bioimpedance analysis is inexpensive, non-invasive and portable, and is widely used in adults for the assessment of body composition. There are currently no prediction algorithms using bioimpedance analysis in neonates that have been directly validated against measurements of fat-free mass (FFM). The aim of the study was to evaluate the use of bioimpedance analysis for the estimation of FFM and percentage of body fat over the first 4 months of life in healthy infants born at term, and to compare these with estimations based on anthropometric measurements (weight and length) and with skinfolds. The present study was an observational study in seventy-seven infants. Body fat content of infants was assessed at birth, 6 weeks, 3 and 4·5 months of age by air displacement plethysmography, using the PEA POD body composition system. Bioimpedance analysis was performed at the same time and the data were used to develop and test prediction equations for FFM. The combination of weight þ sex þ length predicted FFM, with a bias of , 100 g and limits of agreement of 6-13 %. Before 3 months of age, bioimpedance analysis did not improve the prediction of FFM or body fat. At 3 and 4·5 months, the inclusion of impedance in prediction algorithms resulted in small improvements in prediction of FFM, reducing the bias to ,50 g and limits of agreement to ,9 %. Skinfold measurements performed poorly at all ages.

Is body fat percentage a better measure of undernutrition in newborns than birth weight percentiles?

“…Age-and gender-specific densities of fat-free mass were computed based on the data of Fomon et al (35). For neonates up to 6-d-old, this fat-free mass density calculation allows for the greater hydration of fat-free mass in the first week of life (21). FM and fat-free mass were computed from weight and BF% (13).…”

“…ADP has been validated against the four-compartment model and biological and physical phantoms (13) and is considered the criterion method for determining BF% in neonates (14)(15)(16)(17)(18). Several studies have investigated the BF% as the indicator of neonatal nutritional status using ADP (13,(19)(20)(21). However, the neonatal morbidity associated with BF% at birth has not yet been described.…”

Determinants of body composition in breastfed infants using bioimpedance spectroscopy and ultrasound skinfolds—methods comparison

“…The measured impedance, corrected for the reactive component, known as electrical resistance is inversely and quantitatively related to the volume of conductive compartment which can be used to calculate total body water (TBW) and estimate fat-free mass (FFM) and fat mass (FM) (2). BIS provides reliable estimates of TBW in adults and equations have been developed for children and infants (3,4). While in very young infants (<5 mo) BIS is associated with poorer predictive performance that could be due to the higher conductivity of the infant's adipose tissue with its increased vascularization and water content, and rapidly changing hydration status caused by feeding patterns (4-6), small bias indicates that BIS is suitable for comparison between groups and for longitudinal studies (4).…”

“…BIS provides reliable estimates of TBW in adults and equations have been developed for children and infants (3,4). While in very young infants (<5 mo) BIS is associated with poorer predictive performance that could be due to the higher conductivity of the infant's adipose tissue with its increased vascularization and water content, and rapidly changing hydration status caused by feeding patterns (4-6), small bias indicates that BIS is suitable for comparison between groups and for longitudinal studies (4). Ultrasound (US) presents an alternative noninvasive and inexpensive technique to study infant BC.…”

Effects of Acute and 2-Hour Postphysical Activity on the Estimation of Body Fat Made by the Bod Pod

“…BIA's are currently in used in a wide range of settings (ACSM, 2010) as well as across a spectrum of ages (Lingwood et al, 2012;Patil, Patkar, Mandlik, Kuswarkar, & Jindal, 2010), weight classifications (Mattar et al, 2011), body types (Ejike & Ijeh, 2012), and disease status (Kahraman et al, 2010) due to its non-invasive nature, simplistic operation and being readily available.…”