Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 8/1/2004
Publication Date: 9/1/2004
Citation: Ellis, K.J., Yao, M., Heird, W.C., Wong, W.W., Urlando, A., Shypailo, R.J. 2004. Use of a novel pediatric body composition technique for assesing body fatness in infants [abstract]. Obesity Research. (Suppl.)12:A56. Interpretive Summary:
Technical Abstract: The assessment of body composition provides key information for assessing infant growth and for the administration of nutritional and pharmacological interventions. However, the use of body composition methods in infants is limited due to practical considerations, accuracy, and safety. This study evaluated the intra-device reliability and accuracy of an air displacement plethysmograph, the PEA POD Infant Body Composition System (Life Measurement, Inc., Concord, CA), for determining percent body fat (%BF) in infants. The PEA POD reliability was assessed by comparing %BF obtained from same-day repeated tests in 14 full-term infants (4.917.7 wks; 2.76.4 kg). A 4-compartment (4C) model for calculating %BF based on measurements of total body water via deuterium dilution, total body potassium via whole body counter, and bone mineral content via dual-energy x-ray absorptiometry, was used as the criterion method for evaluating the accuracy of %BF estimates from the PEA POD in 10 infants (2.723.0 wks; 4.17.1 kg). There was no significant difference in test-retest mean %BF (=0.031.42 %BF). Within-subject test-retest SD and CV were 0.6 %BF and 3.3%, respectively, indicating excellent intra-device reliability. %BF estimates from the PEA POD were not influenced by subject behavioral state. The regression between %BF by the 4C model and by PEA POD did not significantly deviate from the line of identity [%BF(4C model)=0.95%BF(PEA POD)+3.33, R2=0.84, SEE=2.58 %BF]. Bland-Altman limits of agreement (-7.052.79 %BF) indicated smaller variations in individual agreement between the PEA POD and the criterion method compared to other pediatric body composition techniques. Further, agreement between %BF by PEA POD and 4C model did not vary with body fatness (r=-0.06), and the aqueous (partial r=0.50) or mineral (partial r=-0.02) fractions of fat-free mass. In summary, the PEA POD is a reliable and accurate instrument for determining %BF in infants, and has the potential for widespread use in both research and clinical settings.