COMPARISON OF SKINFOLD AND BIOELECTRICAL IMPEDANCE ANALYSIS WITH DUAL-ENERGY X-RAY ABSORPTIOMETRY FOR BODY COMPOSITION ANALYSIS IN COLLEGE STUDENTS

Dual-energy x-ray absorptiometry (DXA) can provide precise measurement of soft tissue composition with minimal radiation exposure. However, having access to DXA is very costly and limited, and other noninvasive and more accessible techniques such as bioelectrical impedance analysis (BIA) and skinfold measurements are commonly used by clinicians. The purpose of this study was to compare body composition examined with BIA and 3-sites skinfold analysis to the results examined with DXA, and develop body fat prediction equations for BIA and skinfold measurements, using DXA data as the criterion Design: Cross sectional. Subjects: Sixty three college age students (28 male, 35 female) aged 18 to 27 participated in the study. Results: Body fat percentage measured with DXA is significantly higher than those measured with skinfold (p = .01) and BIA (p = .01). However, body fat percentage measured with DXA is highly correlated with those measured with skinfold (r = .895; p = .01) and BIA (r = .875; p = .01). The DXA criterion regression equations were created for skinfold and BIA: DXA%BF=4.65 + 0.43 * S3SF (sum of 3 site skinfold); DXA%BF=3.79 + 1.09 * BIA%BF. The new regression equations were further validated using 75/25% subjects cross validation. Conclusion: Skinfold and BIA measurements significantly underestimate body fat percentage compared to DXA in healthy college students. Adjustments are necessary to accurately predict body fat percentage when using skinfold or BIA at a clinical setting. To accommodate the higher body fat percentage measured with the gold standard such as DXA, the results from this study suggest the need for the current %BF standards and norms for healthy young adults to be adjusted upward.