Dual-energy X-ray absorptiometry lean soft tissue hydration: independent contributions of intra- and extracellular water

2004 ◽  
Vol 287 (5) ◽  
pp. E842-E847 ◽  
Author(s):  
Marie-Pierre St-Onge ◽  
ZiMian Wang ◽  
Mary Horlick ◽  
Jack Wang ◽  
Steven B. Heymsfield
Keyword(s):  
Soft Tissue ◽  
Water Distribution ◽  
Dual Energy ◽  
Healthy Adults ◽  
Intracellular Water ◽  
Whole Body ◽  
Extracellular Water ◽  
Cross Sectional ◽  
Total Group ◽  
X Ray

Dual-energy X-ray absorptiometry (DEXA) provides a measure of lean soft tissue (LST). LST hydration, often assumed to be constant, is relevant to several aspects of DEXA body composition estimates. The aims of this study were to develop a theoretical model of LST total body water (TBW) content and to examine hydration effects with empirically derived model coefficients and then to experimentally test the model's prediction that, in healthy adults, LST hydration is not constant but varies as a function of extra- and intracellular water distribution (E/I). The initial phase involved TBW/LST model development and application with empirically derived model coefficients. Model predictions were then tested in a cross-sectional study of 215 healthy adults. LST was measured by DEXA, extracellular water (ECW) by NaBr dilution, intracellular water (ICW) by whole body 40K counting, and TBW by 2H2O dilution. TBW estimates, calculated as ECW + ICW, were highly correlated with ( r = 0.97, SEE = 2.1 kg, P < 0.001) and showed no significant bias compared with TBW measured by 2H2O. Model-predicted TBW/LST was almost identical to experimentally derived values (means ± SD) in the total group (0.767 vs. 0.764 ± 0.028). LST hydration was significantly correlated with E/I (total group, r = 0.30, SEE = 0.027, P < 0.001). Although E/I increased with age (men, r = 0.48; women, r = 0.37; both P < 0.001), the association between TBW/LST and age was nonsignificant. Hydration of the DEXA-derived LST compartment is thus not constant but varies predictably with ECW and ICW distribution. This observation has implications for the accuracy of body fat measurements by DEXA and the use of TBW as a means of checking DEXA system calibration.

Extracellular water: greater expansion with age in African Americans

2005 ◽  
Vol 99 (1) ◽  
pp. 261-267 ◽  
Author(s):  
Analiza M. Silva ◽  
Jack Wang ◽  
Richard N. Pierson ◽  
ZiMian Wang ◽  
Steven B. Heymsfield ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Healthy Aging ◽  
The Other ◽  
Whole Body ◽  
Fluid Distribution ◽  
Extracellular Water ◽  
Cross Sectional ◽  
Age Related ◽  
The Cross ◽  
Potential Factors

Aging is associated with the onset of chronic diseases that lead to pathological expansion of the extracellular water (ECW) compartment. Healthy aging, in the absence of disease, is also reportedly accompanied by a relative expansion of the ECW compartment, although the studies on which this observation is based are few in number, applied different ECW measurement methods, included small ethnically homogeneous subject samples, and failed to adjust ECW for non-age-related influencing factors. The aim of the current study was to examine, in a large ( n = 1,538) ethnically diverse [African American (AA), Asian, Caucasian, Hispanic] subject group the cross-sectional relationships between ECW and age after controlling first for other potential factors that may influence fluid distribution. ECW and intracellular water (ICW) were derived from measured total body water (isotope dilution) and potassium (40K whole body counting). The cross-sectional relationships between ECW, ICW, and ECW/ICW (E/I), and age were developed using multiple regression modelling methods. Body weight, weight squared, height, age, sex, race, and interactions were all significant ECW predictors. The slope of the observed race × age interaction was significantly greater in AA (β = 0.0005, P = 0.005) than in the three other race groups. Race, sex, and age differences in fluid distribution persisted after adjusting for body composition in a subgroup ( n = 994) with dual-energy X-ray absorptiometry lean soft tissue and fat measurements. A relative ECW expansion (i.e., E/I) was present with greater age in most sex-race groups, although the effect was not significantly larger in AA males ( P > 0.05) compared with the other race groups, except Asians ( P < 0.05). For females, a larger E/I-age effect was found in AA compared with the other race groups, but only the comparison against Hispanics was significant ( P < 0.05). The ECW compartment and E/I are thus variably larger, according to race, in healthy older subjects independent of sex, lean soft tissue, and fat mass.

scholarly journals Creatine (methyl-d3) dilution in urine for estimation of total body skeletal muscle mass: accuracy and variability vs. MRI and DXA

2018 ◽  
Vol 124 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Richard V. Clark ◽  
Ann C. Walker ◽  
Ram R. Miller ◽  
Robin L. O’Connor-Semmes ◽  
Eric Ravussin ◽  
...  
Keyword(s):  
Muscle Mass ◽  
Dual Energy ◽  
Intraindividual Variability ◽  
Whole Body ◽  
Dilution Method ◽  
X Ray ◽  
Spot Urine ◽  
Spot Urine Sample ◽  
Liquid Chromatography Tandem Mass ◽  
Total Body

A noninvasive method to estimate muscle mass based on creatine ( methyl-d3) (D3-creatine) dilution using fasting morning urine was evaluated for accuracy and variability over a 3- to 4-mo period. Healthy older (67- to 80-yr-old) subjects ( n = 14) with muscle wasting secondary to aging and four patients with chronic disease (58–76 yr old) fasted overnight and then received an oral 30-mg dose of D3-creatine at 8 AM ( day 1). Urine was collected during 4 h of continued fasting and then at consecutive 4- to 8-h intervals through day 5. Assessment was repeated 3–4 mo later in 13 healthy subjects and 1 patient with congestive heart failure. Deuterated and unlabeled creatine and creatinine were measured using liquid chromatography–tandem mass spectrometry. Total body creatine pool size and muscle mass were calculated from D3-creatinine enrichment in urine. Muscle mass was also measured by whole body MRI and 24-h urine creatinine, and lean body mass (LBM) was measured by dual-energy X-ray absorptiometry (DXA). D3-creatinine urinary enrichment from day 5 provided muscle mass estimates that correlated with MRI for all subjects ( r = 0.88, P < 0.0001), with less bias [difference from MRI = −3.00 ± 2.75 (SD) kg] than total LBM assessment by DXA, which overestimated muscle mass vs. MRI (+22.5 ± 3.7 kg). However, intraindividual variability was high with the D3-creatine dilution method, with intrasubject SD for estimated muscle mass of 2.5 kg vs. MRI (0.5 kg) and DXA (0.8 kg). This study supports further clinical validation of the D3-creatine method for estimating muscle mass. NEW & NOTEWORTHY Measurement of creatine ( methyl-d3) (D3-creatine) and D3-creatinine excretion in fasted morning urine samples may be a simple, less costly alternative to MRI or dual-energy X-ray absorptiometry (DXA) to calculate total body muscle mass. The D3-creatine enrichment method provides estimates of muscle mass that correlate well with MRI, and with less bias than DXA. However, intraindividual variability is high with the D3-creatine method. Studies to refine the spot urine sample method for estimation of muscle mass may be warranted.

scholarly journals Instrumental diagnosis of osteosarcopenia in diagrams and tables

2021 ◽  
pp. 358-364
Author(s):  
A. V. Naumov ◽  
D. V. Demenok ◽  
Yu. S. Onuchina ◽  
N. O. Khovasova ◽  
V. I. Moroz ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Physical Performance ◽  
Assessment Tool ◽  
Mass Function ◽  
Dual Energy ◽  
Whole Body ◽  
Mineral Density ◽  
X Ray ◽  
Fracture Risk Assessment Tool ◽  
History Of

Osteoporosis and sarcopenia are age-associated diseases of the musculoskeletal system. Osteosarcopenia, the presence of osteopenia/osteoporosis and sarcopenia. The prevalence of osteosarcopenia in older adults with failing was 37% and associated with higher rate of death. Diagnosis of osteosarcopenia consists of describing medical history of fractures, providing x-ray of the spine (if it is needed) and bone densitometry, calculation of Fracture Risk Assessment Tool (FRAX), evaluating muscle strength, mass, function. The most common exam which is used to measure bone mineral density (BMD) is dual-energy x-ray absorptiometry (DXA or DEXA). Screening using the FRAX is recommended in all postmenopausal women and mеn over 50 in order to identify individuals with high probability of fractures. It is recommended to diagnose osteoporosis in patients with fragility fracture of large bones of the skeleton. Diagnosis of sarcopenia is consist of measures for three parameters: muscle strength, muscle quantity/quality and physical performance as an indicator of severity. Muscle strength can be measured with carpal dynamometry. Muscle mass can be evaluated dual-energy X-ray absorptiometry (program «Whole body»). Muscle function can be evaluated with short physical performance battery (SPPB) tests. In this article described algorithm of diagnosis of osteosarcopenia.

scholarly journals A multi-center comparison of dual energy X-ray absorptiometers: In vivo and in vitro soft tissue measurement

1997 ◽  
Vol 51 (5) ◽  
pp. 312-317 ◽  
Author(s):  
CD Economos ◽  
ME Nelson ◽  
MA Fiatarone ◽  
GE Dallal ◽  
SB Heymsfield ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Dual Energy ◽  
X Ray
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