Bioelectrical impedance spectroscopy in growth hormone-deficient adults.
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.
Tengvall
Marja
M
Department of Clinical Nutrition at Sahlgrenska University Hospital, Sahlgrenska Academy at University of Gothenburg, SE 40530 Göteborg, Sweden. marja.tengvall@gu.se
Ellegård
Lars
L
Bosaeus
Niklas
N
Isaksson
Mats
M
Johannsson
Gudmundur
G
Bosaeus
Ingvar
I
D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D001834:Body Water; D017097:Electric Impedance; D045604:Extracellular Fluid; D005260:Female; D020249:Hormone Replacement Therapy; D019382:Human Growth Hormone / Q000172:deficiency* / Q000627:therapeutic use; D006801:Humans; D007424:Intracellular Fluid; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000032:analysis; D011865:Radioisotope Dilution Technique; D012727:Sex Characteristics; D014316:Tritium; D055815:Young Adult
D014316:Tritium; D019382:Human Growth Hormone; D011188:Potassium