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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #94414
Title: BODY WATER MEASUREMENTS IN A MULTIETHNIC PEDIATRIC POPULATION USING MULTIFREQUENCY BIOELECTRICAL IMPEDANCE SPECTROSCOPY

Author
item Ellis, Kenneth
item SHYPAILO, ROMAN - BAYLOR COLLEGE OF MED
item Wong, William

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: It is important to know the most accurate methods of estimating body water compartments in human beings for clinical use, such as in disease assessment and progression. We compared the latest methods to assess body water compartments in three ethnic groups. We found that bioelectrical impedance spectroscopy is equivalent to dual-energy X-ray absorptiometry combined with total body potassium as an estimate of total body water and its distribution on a population basis.

Technical Abstract: The study objective was to evaluate the accuracy of bioelectrical impedance spectroscopy (BIS) for the measurement of total body water (TBW), extracellular water (ECW) and intracellular (ICW) in children and adolescents. BIS, dual-energy X-ray absorptiometry (DXA), and total body potassium (TBK) measurements were performed in 347 healthy children and adolescents [202 males (M), 145 females (F)]. The reference values for TBW ECW, and ICW were defined using a DXA+TBK model. Although the initial BIS values were highly correlated with the reference values (r2=0.94-0.97, p<0.0001), the mean differences between the two methods were significantly nonzero (p<0.001). New BIS calibration constants were derived and tested in a cross-validation group. The mean differences between the BIS and DXA+TBK model for each of the water compartments became zero, and the SD of the difference values were significantly improved (1.8 L for TBW, 1.4 L for ICW, and 1.0 L for ECW) for the total population. Further refinement in accuracy for the BIS measurement of an individual child may be achieved by using age-specific adjustments for the BIS constants.