title: Influence of posture and frequency modes in total body water estimation using bioelectrical impedance spectroscopy in boys and adult males.
abstract: The aim of the study was to examine differences in total body water (TBW) measured using single-frequency (SF) and multi-frequency (MF) modes of bioelectrical impedance spectroscopy (BIS) in children and adults measured in different postures using the deuterium (2H) dilution technique as the reference. Twenty-three boys and 26 adult males underwent assessment of TBW using the dilution technique and BIS measured in supine and standing positions using two frequencies of the SF mode (50 kHz and 100 kHz) and the MF mode. While TBW estimated from the MF mode was comparable, extra-cellular fluid (ECF) and intra-cellular fluid (ICF) values differed significantly (p < 0.01) between the different postures in both groups. In addition, while estimated TBW in adult males using the MF mode was significantly (p < 0.01) greater than the result from the dilution technique, TBW estimated using the SF mode and prediction equation was significantly (p < 0.01) lower in boys. Measurement posture may not affect estimation of TBW in boys and adult males, however, body fluid shifts may still occur. In addition, technical factors, including selection of prediction equation, may be important when TBW is estimated from measured impedance.
authors.affiliation: Institute of Nutrition Sciences, Kagawa Nutrition University, Saitama 350-0288, Japan. mskagawa@eiyo.ac.jp.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Kagawa
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Queensland 4059, Australia. c.wishart@qut.edu.au.
authors.forename: Connie
authors.initials: C
authors.lastname: Wishart
authors.affiliation: Mater Research Institute, the University of Queensland and Griffith Health Institute, Griffith University, Queensland 4101, Australia. ahills@mmri.mater.org.au.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Hills
mesh_terms: D000328:Adult; D001823:Body Composition; D015992:Body Mass Index; D001834:Body Water / Q000378:metabolism*; D001835:Body Weight; D002648:Child; D017097:Electric Impedance; D006801:Humans; D008297:Male; D011187:Posture / Q000502:physiology*