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

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.

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.

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.

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.

The Pollock 3-site method estimates body fat percentage with comparable accuracy to JP7 using ULTRA.