Validity and reliability of a 4-compartment body composition model using dual energy x-ray absorptiometry-derived body volume

Abstract

Background 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. Aims 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). Methods 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. Results 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). Conclusion 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.

Reliability and validity of various laboratory methods of body composition assessment in young adults

“…Those authors reported that estimated BF from CT was well correlated with UWW and BP, but that it was slightly higher than UWW and slightly lower than BP, with pairwise comparisons between BP and UWW confirming this and prior research (McCrory et al ., ; Gibby et al ., ). Both Smith‐Ryan (Smith‐Ryan et al ., ) and (Nickerson et al ., ) have evaluated the 4C DXA model for validity, the former with 4C BP and the latter with 4C UWW . In the former study, the mean differences were 0·84%, −0·8 kg and 0·8 kg for %BF, FFM and FM, respectively (Smith‐Ryan et al ., ).…”

“…Both Smith‐Ryan (Smith‐Ryan et al ., ) and (Nickerson et al ., ) have evaluated the 4C DXA model for validity, the former with 4C BP and the latter with 4C UWW . In the former study, the mean differences were 0·84%, −0·8 kg and 0·8 kg for %BF, FFM and FM, respectively (Smith‐Ryan et al ., ). The latter study found a mean difference of 0·9% BF.…”

“…Another limitation is that, since only two participants had BMIs >30, we cannot generalize the results to overweight or obese individuals; indeed, an examination of the Bland–Altman plots indicates a smaller error with increased fat mass. Fortunately, other studies have conducted reliability and validity testing in overweight and obese individuals (Smith‐Ryan et al ., ; Bailey et al ., ; Blue et al ., ). Further to this, the study was 84% non‐Hispanic white; thus, these data may have differed with a more heterogenous sample given that differences in body fat exist by race/ethnicity (Heymsfield et al ., ).…”

“…Unfortunately, BMI is pervasive in the literature due to its ease as an assessment tool in field and clinical settings. Conversely, assessments of body composition may be limited to laboratory settings, and concerns over cost, reliability and agreement between methods have been cited as limitations to various methods of body composition (Smith-Ryan et al, 2017;Bailey et al, 2018).…”

Validation of rapid 4-component body composition assessment with the use of dual-energy X-ray absorptiometry and bioelectrical impedance analysis

“…Notably, the present study validates the use of specific DXA and BIA systems (from Hologic and InBody) whereas Wilson et al's (7) seminal study used systems from different manufacturers (GE and Impedimed). Smith-Ryan et al (17) used a Hologic DXA system and an Impedimed BIA system. Although the equations presented herein are specifically calibrated to the particular devices (Hologic DXA and InBody BIA) in this study, the success of this validation demonstrates the hardware agnosticism of the 4C DXA + BIA approach.…”