Open AccessFour‐Compartment Cellular Level Body Composition Model: Comparison of Two Approaches **
Author(s) -
Shen Wei,
StOnge MariePierre,
Pietrobelli Angelo,
Wang Jack,
Wang ZiMian,
Heshka Stanley,
Heymsfield Steven B.
Publication year - 2005
Publication title -
obesity research
Language(s) - English
Resource type - Journals
eISSN - 1550-8528
pISSN - 1071-7323
DOI - 10.1038/oby.2005.8
Subject(s) - body water , bromide , extracellular fluid , chemistry , body weight , dilution , potassium bromide , extracellular , compartment (ship) , zoology , medicine , biochemistry , biology , physics , oceanography , organic chemistry , thermodynamics , geology
Objective: The aim of this study was to develop and compare two DXA‐based four‐compartment [body weight = body cell mass (BCM) + extracellular fluid (ECF) + extracellular solids (ECS) + fat] cellular level models. Research Methods and Procedures: Total body potassium (TBK) model: BCM from TBK by whole‐body counting—ECF TBK = LST − [BCM TBK + 0.73 × osseous mineral (Mo)]. Bromide model: ECF from sodium bromide dilution—BCM BROMIDE = LST − (ECF BROMIDE + 0.73 × Mo); Mo and LST measurements came from DXA. The two approaches were evaluated in 99 healthy men and 118 women. Results: BCM estimates were highly correlated ( r = 0.97, p < 0.001), as were ECF estimates (r = 0.87, p < 0.001); a small statistically significant mean difference was present (mean ± SD; BCM TBK model, 30.4 ± 8.9 kg; BCM BROMIDE , 31.4 ± 9.3 kg; Δ = 1.0 ± 2.8 kg; p < 0.001; ECF TBK , 18.5 ± 4.2 kg; ECF BROMIDE , 17.5 ± 3.6 kg; Δ = 1.0 ± 2.8 kg; p < 0.001). A high correlation ( r = 0.97, p < 0.001) and good agreement (38.9 ± 9.5 vs. 38.9 ± 9.5 kg; Δ = 0.0 ± 2.4 kg; p = 0.39) were present between TBW, derived as the sum of intracellular water from TBK and ECW from bromide, and measured TBW by 2 H 2 O dilution. Discussion: Two developed four‐compartment cellular level DXA models, one of which is appropriate for use in most clinical and research settings, provide comparable results and are applicable for BCM and ECF estimation of subject groups with hydration disturbances.