Although obesity is typically considered a health risk factor, the pattern of fat distribution, especially in the abdominal region, is more strongly related to chronic metabolic and cardiovascular disease. Several field methods have been used to evaluate body composition and determine obesity status. However, none of these technique can appropriately quantify abdominal obesity. Therefore, an alternative field method of body composition that can distinguish levels of abdominal fat needs to be developed. The segmental bioelectric impedance analysis technique (SBIA) may lead to an alternative way of evaluating body fat distribution. The purpose of this study was to compare two different bioelectric impedance analysis (BIA) measurement techniques, whole BIA (WBIA) and SBIA with hydrodensitometry (UWW) to assess body fat (% BF) in obese women with distinctly different body fat distribution patterning. A secondary purpose was to determine the potential for SBIA to distinguish body fat patterning. Seventeen, premenopausal women were matched for age (X = 35.29±5.27 yrs) and BMI (X = 31.40±4.30) and placed by waist to hip ratio (WHR) into two distinct groups: upper body obesity (UBO, n=9; WHR > 0.85) and lower body obesity (LBO, n=8; WHR < 0.77). A two group by three method repeated measures ANOVA was used to determine differences in % BF. Percent of body fat (% BF) for BIA was determined from the Segal, et al., (1988) equation. SBIA was calculated using the procedures of Chumlea, et al., (1988). WBIA and SBIA significantly (p=0.001) overestimated % BF as compared to UWW in both group. No significant method by group interaction was found. Significant (p< .05) negative correlations were found between the proportional fat at arm and WHR (r = -.537). Also, a significant (p <.01) negative relationship was found between the proportional fat at leg with the trunk (r = -.854). In addition, a significant (p < .05) correlation was indicated between the proportional fat at trunk and waist circumference (r = -.532). In summary, the data indicate that WBIA and SBIA overestimate % BF in moderately obese women regardless of body fat distribution pattern. Also the SBIA method was not able to conclusively differentiate body fat distribution between UBO and LBO groups. However, it was clear that by using SBIA technique the peripheral segmental measures were highly correlated with each other and negatively associated with the central or abdominal trunk segment. These data indicate that the SBIA technique may hold promise as a possible screening method for identifying those with the clinically significant UBO body fat pattern.

Keywords: Body composition, Body fat, Body fat distribution, Bioelectric Impedance analysis