| 1. |
- Tengvall, Marja, 1982, et al.
(författare)
-
Bioelectrical impedance spectroscopy in growth hormone-deficient adults.
- 2010
-
Ingår i: Physiological measurement. - : IOP Publishing. - 1361-6579 .- 0967-3334. ; 31:1, s. 59-75
-
Tidskriftsartikel (refereegranskat)abstract
- This study evaluated water compartment assessment by bioelectrical impedance spectroscopy (BIS) by Xitron 4000B in 164 growth hormone-deficient adults on growth hormone replacement therapy, examined the assumed constant body density and gender-specific resistivities in BIS methodology and evaluated a published BMI-adjusted BIS equation. Body composition was measured by BIS, total body potassium (TBK), tritium dilution and dual-energy x-ray absorptiometry (DXA). Tritium dilution and TBK were combined to a reference method for water compartments. Average difference for total body water (TBW) by tritium dilution and by BIS was 0.6 l in women (p > 0.05) and -0.2 l in men (p > 0.05). Average extracellular water (ECW) by the reference method and by BIS differed 1.5 l in women (p < 0.05) and 1.2 l in men (p < 0.05). Average intracellular water (ICW) by the reference method and by BIS differed -0.9 l in women (p < 0.05) and -1.3 l in men (p < 0.05). However, average ECW and ICW could be successfully estimated by BIS with use of unisex resistivity constants that were derived from this population, although with large individual variation. Average individual body density was lower than assumed. Application of individual body density did not improve agreement between methods. BMI-adjusted equations were not fully accurate in this population.
|
|
| 2. |
- Tengvall, Marja, 1982, et al.
(författare)
-
Body composition in the elderly: Reference values and bioelectrical impedance spectroscopy to predict total body skeletal muscle mass
- 2009
-
Ingår i: Clinical Nutrition. - : Elsevier BV. - 0261-5614 .- 1532-1983. ; 28:1, s. 52-58
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: To validate the bioelectrical impedance spectroscopy (BIS) model against dual-energy X-ray absorptiometry (DXA), to develop and compare BIS estimates of skeletal muscle mass (SMM) to other prediction equations, and to report BIS reference values of body composition in a population-based sample of 75-year-old Swedes. METHODS: Body composition was measured by BIS in 574 subjects, and by DXA and BIS in a subset of 98 subjects. Data from the latter group was used to develop BIS prediction equations for total body skeletal muscle mass (TBSMM). RESULTS: Average fat free mass (FFM) measured by DXA and BIS was comparable. FFM(BIS) for women and men was 40.6kg and 55.8kg, respectively. Average fat free mass index (FFMI) and body fat index (BFI) for women were 15.6 and 11.0. Average FFMI and BFI for men were 18.3 and 8.6. Existing bioelectrical impedance analysis equations to predict SMM were not valid in this cohort. A TBSMM prediction equation developed from this sample had an R(pred)(2) of 0.91, indicating that the equation would explain 91% of the variability in future observations. CONCLUSIONS: BIS correctly estimated average FFM in healthy elderly Swedes. For prediction of TBSMM, a population specific equation was required.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
