Validity and reliability of a 4-compartment body composition model using dual energy x-ray absorptiometry-derived body volume
Published Date:May 15 2016
Source:Clin Nutr. .
Pubmed Central ID:PMC5110400
Funding:KL2 TR001109/TR/NCATS NIH HHS/United States
P30 DK056350/DK/NIDDK NIH HHS/United States
T42 OH008673/OH/NIOSH CDC HHS/United States
Body volume (BV), one component of a four-compartment (4C) body composition model, is commonly assessed using air displacement plethysmography (BodPod). However, dual-energy x-ray absorptiometry (DEXA) has been proposed as an alternative method for calculating BV.
This investigation evalauted the validity and reliability of DEXA-derived BV measurement and a DEXA-derived 4C model (DEXA-4C) for percent body fat (%BF), fat mass (FM), and lean mass (LM).
A total sample of 127 men and women (Mean ± SD; Age: 35.8 ± 9.4 years; Body Mass: 98.1 ± 20.9 kg; Height: 176.3 ± 9.2 cm) completed a traditional 4C body composition reference assessment. A DEXA-4C model was created by linearly regressing BodPod BV with DEXA FM, LM, and bone mineral content as independent factors. The DEXA-4C model was validated in a random sub-sample of 27 subjects. Reliability was evaluated in a sample of 40 subjects that underwent a second session of identical testing.
When BV derived from DEXA was applied to a 4C model, there were no significant differences in %BF (p=0.404), FM (p=0.295), or LM (p=0.295) when compared to the traditional 4C model. The approach was also reliable; BV was not different between trials (p=0.170). For BV, %BF, FM, and LM relative consistency values ranged from 0.995-0.998. Standard error of measurement for BV was 0.62L, ranging from 0.831-0.960kg. There were no significant differences between visits for %BF (p=0.075), FM (p=0.275), or LM (p=0.542).
The DEXA-4C model appears to be a valid and reliable method of estimating %BF, FM, and LM. The prediction of BV from DEXA simplifies the acquisition of 4C body composition by eliminating the need for an additional BV assessment.
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