¹Institute for Biomedical Engineering, Technical University Graz, Austria

²Institute for Adaptive and Spaceflight Physiology, Austrian Society for Aerospace Medicine, Graz, Austria

³Magnetic Resonance Institute, School of Medicine, Karl-Franzens University, Graz, Austria

⁴Volume Regulation and Space Medicine Research Group, Department of Physiology, School of Medicine, Karl-Franzens University, Graz, Austria

Correspondence to: H Scharfetter, Institute for Biomedical Engineering, Technical University Graz, Inffeldgasse 18, A-8010 Austria. E-mail: scharfetter@bmt.tu-graz.ac.at

OBJECTIVE: Abdominal fat is of major importance in terms of body fat distribution but is poorly reflected in conventional body impedance measurements. We developed a new technique for assessing the abdominal subcutaneous fat layer thickness (SFL) with single-frequency determination of the electrical impedance across the waist (SAI).

SUBJECTS AND MEASUREMENTS: The method uses a tetrapolar arrangement of surface electrodes which are placed symmetrically to the umbilicus in a plane perpendicular to the body axis. Twenty-four test subjects (12 male, 12 female) underwent SAI and abdominal magnetic resonance imaging (MRI). The SFL below the sensing electrodes was determined from MRI and correlated with the SAI data at four different frequencies (5, 20, 50 and 204 kHz).

RESULTS: A highly significant linear correlation (r²=0.99) between SFL and SAI over a wide range of the abdominal SFL was found. Separate regression models for female and male subjects did not differ significantly, except at 50 kHz.

CONCLUSION: SAI represents a good predictor of the SFL and provides an excellent tool for the assessment of central obesity.

International Journal of Obesity (2001) 25, 502-511

abdominal bioimpedance; central obesity; fat layer thickness