Estimates of body fat in children by Hologic QDR-2000 and QDR-4500A dual-energy X-ray absorptiometers compared with deuterium dilution.
We evaluated the accuracy with which the Hologic QDR-4500A and QDR-2000 densitometers measure fat mass (FM) in 95 children. FM was derived from total body water measured by deuterium dilution (DD) in all children, by QDR-4500A in 50, and by QDR-2000 in 45 children. Compared with DD, both instruments underestimated FM (QDR-4500A: 3.35 +/- 2.5 kg, P < 0.0001; QDR-2000: 1.05 +/- 1.5 kg, P < 0.0001). Both absorptiometers showed magnitude biases relative to DD (QDR-4500: r = +0.70, P < 0.001; QDR-2000: r = -0.51, P < 0.001). We conclude that neither densitometer is equivalent to DD for estimation of children's FM. The QDR-4500A's current calibration seems to provide an even greater underestimate of FM than the QDR-2000.
Unit on Growth and Obesity, Developmental Endocrinology Branch, NICHD, National Institutes of Health, DHHS, Bethesda, MD 20892, USA.
Delphine R
DR
Robotham
Dale A
DA
Schoeller
Arlene B
AB
Mercado
Margaret C
MC
Mirch
Kelly R
KR
Theim
James C
JC
Reynolds
Jack A
JA
Yanovski
D015502:Absorptiometry, Photon / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D000273:Adipose Tissue; D001823:Body Composition / Q000502:physiology*; D001834:Body Water / Q000378:metabolism; D002138:Calibration; D002648:Child; D003903:Deuterium; D005260:Female; D006801:Humans; D008297:Male
D003903:Deuterium