Body fat percentage assessment using skinfold thickness agrees with measures obtained by DXA scan in African American and Caucasian American women.

Abstract

Dual-energy x-ray absorptiometry (DXA) is considered to have high accuracy in estimating fat mass; however, DXA is not always available. We hypothesized that the equations most commonly used for predicting body fat percentage (BF%) using skinfold thickness agree with direct measures of BF% obtained by DXA scan in African American (AA) and Caucasian American (CA) women. Data from 42 women from Alabama who were 21 to 45 years of age, who self-identify as AA (n = 20) or CA (n = 22) were included. BF% was estimated using DXA scan and through 6 different skinfold thickness equations. Agreement between DXA-BF% and BF% based on the skinfold thickness equations was assessed following the Bland-Altman method (bias and agreement limits). Agreement analysis showed in both AA and CA women that the BF%-Siri equation reflects better agreement and lower mean differences (bias) with BF%-DXA than the BF%-Brozek equation after applying 4 body density (BD) equations. Limits showed that BF%-Siri and BF%-Brozek predictive equations overestimate BF% compared with DXA-BF% in both AA and CA women. In AAs, equations that overestimated less were Wilmore and Behnke-Siri (by 1.81%) and Durnin and Womersley-Siri (by 2.5%) equations. Regarding CAs, equations that overestimated less were Durnin and Womersley-Siri (by 2.74%) and Wilmore and Behnke-Siri (by 3.11%) equations. The results of this study show that the BF%-Siri equation is a more accurate alternative than the BF%-Brozek equation for the calculation of BF%. In the calculation of BD, the Wilmore and Behnke equation in AA women and Durnin and Womersley in CA women were those that overestimated BF% to a lesser degree.