Comparing single-frequency bioelectrical impedance analysis against deuterium dilution to assess total body water

• Published in: European journal of clinical nutrition Vol. 66; no. 9; pp. 994 - 997
• Main Authors: Haas, V, Schütz, T, Engeli, S, Schröder, C, Westerterp, K, Boschmann, M
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.09.2012; Nature Publishing Group
• Subjects: 692/699/1702; 692/700/139/1449; 692/700/139/1735; Adult; Albumins; Anthropometry; Bioelectricity; Biological and medical sciences; Body Composition; Body fluids; Body water; Body Water - chemistry; Body Water - metabolism; Clinical Nutrition; Composition; Creatinine; Deuterium; Deuterium Oxide - chemistry; Deuterium Oxide - metabolism; Dilution; Electric Impedance; Epidemiology; Evaluation; Extracellular Fluid - chemistry; Feeding. Feeding behavior; Female; Frequency analysis; Fundamental and applied biological sciences. Psychology; Gender; Heavy water; Humans; Impedance; Impedance, Bioelectric; Internal Medicine; Isotope dilution techniques; Male; Measurement; Measurement techniques; Medical sciences; Medicine; Medicine & Public Health; Men; Metabolic Diseases; original-article; Outliers (statistics); Population studies; Public Health; Radioisotope Dilution Technique; Sodium; Urea; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Water; Water in the body; Germany; body composition; body shape; bioelectrical impedance analysis; total body water; Water; Dilution; Frequency; Metabolic diseases; Impedance; Body composition; Comparative study
• ISSN: 0954-3007; 1476-5640; 1476-5640
• DOI: 10.1038/ejcn.2012.96

Background/Objectives: In this study, we aimed to validate the accuracy of single-frequency bioelectrical impedance analysis (SF-BIA) at 50 kHz to assess total body water (TBW) against the reference technique deuterium dilution (D 2 O) and to explore if the simple clinical parameters extracellular fluid (ECF) composition and body shape explain individual differences between D 2 O and SF-BIA ( Diff BIA - D 2 O ). Subjects/Methods: We assessed TBW with D 2 O and SF-BIA in 26 women and 26 men without known disease or anomalous body shapes. In addition, we measured body shape with anthropometry and ECF composition (osmolality, albumin, glucose, urea, creatinine, sodium and potassium). Results: On group average, SF-BIA to predict TBW agreed well with D 2 O (SF-BIA, 39.8±10.1 l; D 2 O, 40.4±10.2 l; and Diff BIA – D 2 O −0.7 l). In four individuals (‘outliers’; 15% of the study population), Diff BIA – D 2 O was high (−6.8 to +3.8 l). Diff BIA – D 2 O was associated with individual variations in body shape rather than ECF composition. Using gender-specific analysis, we found that individual variability of waist circumference in men and arm length in women significantly contributed to Diff BIA – D 2 O . When removing the four ‘outliers’, these associations were lost. Conclusions: In the majority of our sample, BIA agreed well with D 2 O. Adjusting for individual variability in body shape by anthropometrical assessment could possibly improve the accuracy of SF-BIA for individuals who deviate from mean values with respect to body shape. However, further studies with higher subject numbers are needed to confirm our findings.