Background: A better understanding of the associations of early infant nutrition and growth with adult health requires accurate assessment of body composition in infancy. Objective: This study evaluated the performance of an infant-sized air-displacement plethysmograph (PEA POD Infant Body Composition System) for the measurement of body composition in infants. Design: Healthy infants (n ҃ 49; age: 1.7-23.0 wk; weight: 2.7-7.1 kg) were examined with the PEA POD system. Reference values for percentage body fat (%BF) were obtained from a 4-compartment (4-C) body-composition model, which was based on measurements of total body water, bone mineral content, and total body potassium. Results: Mean (ȀSD) reproducibility of %BF values obtained with the PEA POD system was 0.4 Ȁ 1.3%. Mean %BF obtained with the PEA POD system (16.9 Ȁ 6.5%) did not differ significantly from that obtained with the 4-C model (16.3 Ȁ 7.2%), and the regression between %BF for the 4-C model and that for the PEA POD system (R 2 ҃ 0.73, SEE ҃ 3.7%BF) did not deviate significantly from the line of identity (y ϭ x). Conclusions: The PEA POD system provided a reliable, accurate, and immediate assessment of %BF in infants. Because of its ease of use, good precision, minimum safety concerns, and bedside accessibility, the PEA POD system is highly suitable for monitoring changes in body composition during infant growth in both the research and clinical settings.Am J Clin Nutr 2007;85:90 -5.

ADP is a reliable and accurate instrument for determining %BF in infants, and it has the potential for use in both research and clinical settings.

This article introduces and evaluates the PEA POD Infant Body Composition System, an air displacement plethysmograph designed for the assessment of body composition in infants between birth and 6 mo of age. The performance of the PEA POD was evaluated by repeated testing of National Institute of Standards and Technology-traceable weights and volumes. Mass was measured in a single session. Volume was measured in four sessions during a 2-d period (five times/session for both). The mean values for repeated mass measurements were almost identical to the masses of traceable weights. The SD and CV for repeated volume measurements were 1.1-4.5 mL and 0.02-0.09%, respectively. Both the mean SD and CV were within very narrow ranges (1.4-3.1 mL for SD and 0.03-0.08% for CV) across all volume levels. Furthermore, mean CV values using results from the four sessions indicated excellent within- and between-day reliability. Regression analyses (by session or with all sessions combined) of the measured volume against actual volume gave very low standard error of the estimate (SEE) (0.853-1.957 mL) and very high R(2) (1.000), with the intercept and slope not significantly different from 0 and 1, respectively. The mean percentage error in volume measurements was < or =0.05% at all volume levels. The study findings and the operational and physical characteristics of the system indicate that the PEA POD has the potential to provide clinicians and researchers with a diagnostic and research tool that is accurate, easily used by operators, and comfortable for subjects.

ADP provides a highly precise and accurate estimate of %Fat in bovine tissue phantoms in the pediatric ranges of body weight and body fatness.

A preliminary evaluation of a new air displacement plethysmography (ADP) system for body composition assessment in infants was performed on 17 subjects on 2 consecutive days. Mean (+/-SD) percent body fat (%BF) obtained from test 1 on day 1, and tests 1 and 2 on day 2 was 23.21+/-7.63, 22.94+/-7.50, and 22.55+/-7.61, respectively. Mean differences in %BF of within- (-0.39+/-0.81) and between-day tests (-0.27+/-0.97) did not significantly differ from zero. %BF 95% limits of agreements were very close (-2.0-1.2, and -2.2-1.7 for within- and between-day tests, respectively). %BF SDs (0.52 and 0.60 %BF for within- and between-day reliability, respectively) were not a function of the subject's behavioral state, body weight, or %BF. Mean %BF obtained from the 3 tests (22.90+/-7.56) was comparable with expected %BF values calculated using data from multi-compartment studies (25.84+/-8.39 and 21.93+/-4.46).