Validity of a new abdominal bioelectrical impedance device to measure abdominal and visceral fat: comparison with MRI

Abdominal fat, and in particular, visceral adipose tissue (VAT), is the critical fat depot associated with metabolic aberrations. At present, VAT can only be accurately measured by computed tomography or magnetic resonance imaging (MRI). This study was designed to compare a new abdominal bioelectrical impedance (BIA) device against total abdominal adipose tissue (TAAT) and VAT area measurements made from an abdominal MRI scan, and to assess its reliability and accuracy. One-hundred twenty participants were recruited, stratified by gender and BMI. Participants had triplicate measures of abdominal fat and waist circumference (WC) with the AB-140 (Tanita, Tokyo, Japan) and WC measurements using a manual tape measure. A single abdominal MRI scan was performed as the reference method. Triplicate measures with the AB-140 showed excellent precision for "visceral fat level," trunk fat %, and WC. AB-140 "visceral fat level" showed significantly stronger correlations with MRI TAAT area than with MRI VAT area (r = 0.94 vs. 0.65 in men and 0.92 vs. 0.64 in women). AB-140 WC showed good correlation with manual WC measurements (r = 0.95 in men and 0.90 in women). AB-140 and manual WCs showed comparable correlations with MRI TAAT area (r = 0.92 and 0.96 in men and 0.88 and 0.88 in women). AB-140 is a simple, quick, and precise technique to measure abdominal fat and WC in healthy adults. It provides a useful proxy for TAAT measured by MRI, comparable to the correlation obtained with manual WC measurements. Neither the AB-140 abdominal fat measures nor WC measurement appear to provide a useful proxy measure of VAT.