Evaluation of body composition using three different methods compared to dual‐energy X‐ray absorptiometry

Abstract

In this study, we compared the simple methods of skinfolds, ultrasound, and bioelectrical impedance analysis (BIA) against the standard of dual-energy X-ray absorptiometry (DEXA) in the assessment of body fat in normoactive Turkish male and female university students. We wished to develop new regression equations to more accurately predict percent body fat from skinfolds and ultrasound for this group of individuals. One hundred and four male (age 22.292.5 years; height 1.7790.06 m; mass 74.9910.4 kg) and one hundred and four female (age 21.991.9 years; height 1.6590.06 m; mass 55.697.9 kg) students aged 18Á26 years participated in the study. Analysis of variance and confidence intervals were used to compare mean percent body fat derived from skinfolds, ultrasound, BIA, and DEXA measurements, while intra-class correlation coefficients and Pearson correlation coefficients were used to evaluate the strength of the relationship between the methods. Bland and Altman plot analysis was used to evaluate the strength of agreement of the three methods with DEXA. Moreover, multiple regression analyses were conducted to develop new regression equations to predict percent body fat from subcutaneous fat thickness measured at three sites. The accuracy of the predictive equations was assessed by a crossvalidation test. Mean percent body fat derived from DEXA (18.596.2% for males, 28.491.3% for females) was found to be significantly (pB0.01) greater than that derived from skinfolds (12.495.5% for males, 20.891.0% for females), ultrasound (12.097.8% for males, 25.091.4% for females), and BIA (13.794.9% for males, 19.291.0% for females) in both males and females. According to the Bland and Altman plot analysis, ultrasound gave the closest results to DEXA for females and males and females combined, whereas BIA gave the closest results to DEXA for males. Skinfolds were the second closest measure to DEXA for all groups. Results of the regression analysis showed that measurement of subcutaneous fat thickness at three sites by skinfolds and ultrasound best predicted percent body fat for males and females respectively. Multiple correlations using three sites simultaneously in the skinfold measurements were r 00.92 (/ ŝ02.4) and r 00.91 (/ ŝ02.8), and in the ultrasound measurements were r 00.93 (/ ŝ02.3) and r00.90 (/ ŝ03.0), for males and females respectively. In conclusion, comparison of the methods revealed that the three techniques could not be used interchangeably in this population. However, with these new regression equations, ultrasound and skinfolds are confirmed to be accurate, portable, and non-invasive tools for use in field studies. As a result, ultrasound can be used accurately on all individuals, regardless of whether they are obese or thin.

A comparison of dual energy X-ray absorptiometry and bioelectrical impedance analysis to measure total and segmental body composition in healthy young adults

“…These diVerences were not found to be statistically signiWcant. Similarly, Duz et al (2009) studied college students aged 18-26 (104 men, 104 women) and found BIA to underestimate % body fat by 4.8% in men and 9.2% in women with an increase in bias as the mean percentage body fat increased, but this bias was not investigated further. In older adults, BIA is reported to underestimate the percentage body fat in men and women (Deurenberg et al 2001;Sun et al 2005;Wattanapenpaiboon et al 1998).…”

Validity and reliability of bioelectrical impedance analysis to estimate body fat percentage against air displacement plethysmography and dual‐energy X‐ray absorptiometry

“…The number of studies comparing BIA to other methods of assessing body composition (primarily DXA) is as varied in their results as the range of BIA equipment available . BIA models considered in other comparison studies include foot‐to‐foot and ankle‐to‐wrist electrode systems, as well as stand‐on, 8‐point models such as the one used in this study.…”

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

“…The results of the present study also concur with Duz et al . () who found ULTRA to underestimate per cent body fat when compared with DXA in young healthy subjects using the Jackson–Pollock three site. Loenneke et al .…”

“…Additionally, Duz et al . () found ULTRA to significantly underestimate %BF using Jackson–Pollock three‐site method versus DXA among college‐aged students. The purpose of the present study was twofold 1) to compare the seven‐site (JP7) ultrasound % BF estimation to two different three‐site methods first a Jackson–Pollock equation (JP3) and then a Pollock (P3) equation and 2) to validate all three methods (JP7, JP3 and P3) against DXA estimates of % BF.…”