Percent Fat Estimates For Obese Adults Using Octapolar Bioimpedance Spectroscopy, DXA, 2C And 4C Models

Abstract

PURPOSE: to compare %BF from two octapolar bioimpedance spectroscopy (BIS) analyzers, DXA, hydrodensitometry (HW) using Siri's 2C model, and Selinger's 4C model for obese (BMI ≥ 30 kg/m2) men (n = 18) and women (n = 16). METHODS: Participants received standard pre-test guidelines within 48 hr of their appointment. Prior to testing, all gave a brief health history, written consent, and voided. Barefoot standing height and weight were obtained in duplicate to the 0.1cm and 0.1kg, respectively, while the participants were clad for HW. Two BIS trails were performed using each octapolar analyzer and a traditional tetrapolar analyzer. A single, medium speed, whole-body DXA scan was obtained. Two dry-land residual volumes within 0.1L were averaged to correct HW body volume using the mean of the 3 heaviest weights within 100g. Siri's 2C conversion formula was used to convert Db into %BF for HW. For Selinger's 4C model water, mineral, and Db were derived from tetrapolar BIS, DXA, and HW, respectively. Equipment was calibrated each testing session. Method (5) x sex (2) repeated measures ANOVA and paired t-tests were performed. RESULTS: Within- and between-subjects effects were noted for method and sex, respectively (p < .001). There were no significant interaction effects. Paired t-tests indicated %BF from DXA was significantly higher by gender and method. Men were leaner than the women (p < .001).Table: Caption not availableCONCLUSIONS: %BF from DXA was consistently higher than the %BF from the other four methods (p < .001). The %BF values from HW, BIS, and Selinger's 4C model were similar within sex. Supported by: NSF MRI Grant, Biospace Co, Ltd, Seoul, Korea