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

Abstract

<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Background</jats:title> <jats:p>The 4-component (4C) model is a criterion method for human body composition that separates the body into fat, water, mineral, and protein, but requires 4 measurements with significant cost and time requirements that preclude wide clinical use. A simplified model integrating only 2 measurements—dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA)—and 10 min of patient time has been proposed.</jats:p> </jats:sec> <jats:sec> <jats:title>Objective</jats:title> <jats:p>We aimed to validate a rapid, simplified 4C DXA + BIA body composition model in a clinical population.</jats:p> </jats:sec> <jats:sec> <jats:title>Design</jats:title> <jats:p>This was a cross-sectional observational study of 31 healthy adults. Participants underwent whole-body DXA, segmental BIA, air displacement plethysmography (ADP), and total body water (TBW) measurement by deuterium (D2O) dilution. 4C composition was calculated through the use of the Lohman model [DXA mineral mass, D2O TBW, ADP body volume (BV), scale weight] and the simplified model (DXA mineral mass and BV, BIA TBW, scale weight). Accuracy of percentage of fat (%Fat) and protein measurements was assessed via linear regression. Test-retest precision was calculated with the use of duplicate DXA and BIA measurements.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Of 31 participants, 23 were included in the analysis. TBWBIA showed good test-retest precision (%CV = 5.2 raw; 1.1 after outlier removal) and high accuracy to TBWD2O [TBWD2O = 0.956*TBWBIA, R2= 0.92, root mean squared error (RMSE) = 2.2 kg]. %Fat estimates from DXA, ADP, D2O, and BIA all showed high correlation with the Lohman model. However, only the 4C simplified model provides high accuracy for both %Fat (R2 = 0.96, RMSE = 2.33) and protein mass (R2= 0.76, RMSE = 1.8 kg). %Fat precision from 4C DXA + BIA was comparable with DXA (root mean square-SD = 0.8 and 0.6 percentage units, respectively).</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>This work validates a simplified 4C method that measures fat, water, mineral, and protein in a 10-min clinic visit. This model has broad clinical application to monitor many conditions including over/dehydration, malnutrition, obesity, sarcopenia, and cachexia.</jats:p> </jats:sec>

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

“…The sample size is on the small end for repeatability and validity research, and an uneven number of male/female participants may have limited the ability to detect sex*assessment differences. Recent work has included smaller (Ng et al ., ), and 2–4 times larger (Nickerson et al ., ; Smith‐Ryan et al ., ; Bailey et al ., ) sample sizes. Finally, the age range of the present study was rather narrow.…”

“…The latter study found a mean difference of 0Á9% BF. A newly published study by Ng and colleagues also evaluated the 4C DXA for validity against isotopic dilution and 4C BP (Ng et al, 2018) . The root mean square after removing outliers from this study was 0Á8% body fat (Ng et al, 2018).…”

“…A newly published study by Ng and colleagues also evaluated the 4C DXA for validity against isotopic dilution and 4C BP (Ng et al, 2018) . The root mean square after removing outliers from this study was 0Á8% body fat (Ng et al, 2018). These values are broadly similar to what we observed in the present study using 4C BP as a criterion compared to 4C UWW and 4C DXA .…”

“…It is important to note that while using 4C DXA would require only two measurements (DXA scan + TBW assessment), Nickerson has argued that it does not provide any greater accuracy compared to other 4C models, and the point of a 4C model is to be as accurate and precise as possible (Nickerson et al, 2017a(Nickerson et al, , 2017c. On the other hand, Ng found that this technique incorporating BIA and DXA was accurate and repeatable compared with a criterion 4C model (Ng et al, 2018). However, it should be noted that the studies of Smith-Ryan and Nickerson used the 4C model of Wang, while Ng used the 4C model of Lohman (Nickerson et al, 2017a;Smith-Ryan et al, 2017;Ng et al, 2018).…”

“…The currently accepted 'gold standard' for assessing body composition is the four-compartment model (4C) (Ng et al, 2018). This method uses body volume (BV), total body mineral content (Mo), TBW and body mass (BM) to calculate FM.…”