Seven-site versus three-site method of body composition using BodyMetrix ultrasound compared to dual-energy X-ray absorptiometry

Summary Obesity is a steadily growing epidemic affecting all segments of the population including college-aged students. The weight gain that is evidenced amid the transitional stage of college years increases the risks associated with cardiovascular and metabolic diseases. The BodyMetrix® BX-2000 (ULTRA) using a seven-site method has been evaluated against dual-energy X-ray absorptiometry (DXA) for estimation of body composition, which has yielded conflicting results. To date, no studies have compared the three-site method Jackson and Pollock three-site method to DXA. Purpose The purpose of the study was twofold (i) to compare agreement between Jackson–Pollock seven site (JP7), Jackson–Pollock three site (JP3) and Pollock three site (P3) to predict body fat (%BF) using ULTRA and (ii) and to compare the three ULTRA methodologies against DXA. Methods Seventy-six healthy college-aged subjects (ages = 22·08 ± 2·50 years) participated in this study. DXA and ULTRA body composition assessments were performed following manufacturer's instructions to estimate %BF. Paired sample t-tests were used to assess agreement between JP7, P3 and JP3. Additionally, a two-tailed sample t-test was performed by sex. ULTRA and DXA results were also performed for agreement and bivariate correlation. Results No significant differences between JP7 and P3, P = 0·38, were observed. In males, no significant differences were observed between JP7 and P3, P = 0·18. Significant differences were observed in all other pairs, P≤0·001 and between ULTRA and DXA. Conclusions The Pollock 3-site method estimates body fat percentage with comparable accuracy to JP7 using ULTRA.