Bioelectrical impedance analysis to assess body composition in obese adult women: The effect of ethnicity

Abstract

OBJECTIVE: To examine whether the accuracy of bioelectrical impedance analysis (BIA) to estimate body composition in overweight women is affected by the ethnicity of the individuals. DESIGN: Cross-sectional design to compare body composition estimated by BIA to body composition measured by dual energy x-ray absorptiometry (DEXA), which was the reference method. SUBJECTS: One hundred twenty three overweight women participated in this study, of which 43 women were African-American (aged 37.2 AE 5.6 y; BMI, 32.3 AE 4.9 kg/m 2 ) and 80 were Caucasian (aged 36.1 AE 5.7 y; BMI, 31.9 AE 3.5 kg/m 2 ). MEASUREMENTS: Body composition was estimated from BIA using both a generalized and an obesity-speci®c equation. These estimations were compared to body composition measured by DEXA, which was the reference method. RESULTS: The generalized BIA equation underestimated lean body mass (LBM) by 2.6 AE 3.1 kg in Caucasian women and 0.4 AE 3.2 kg in African-American women, with the difference between the ethnic groups being signi®cant (P`0.001). The obesity-speci®c equation underestimated LBM in Caucasians by 0.9 AE 3.1 kg and overestimated LBM in African-Americans by 1.2 AE 2.8 kg (P`0.001). An ethnic-speci®c equation is proposed, and cross-validation of this equation indicates that it provides a reasonable estimate of body composition in overweight women. CONCLUSIONS: The accuracy of BIA to estimate body composition appears to be affected by the ethnicity of the individual. Therefore, an ethnic-speci®c equation for overweight women is proposed. However, further validation of this prediction model in an ethnically diverse population is necessary.

Behavior of a New Equation using Bio- Impedancemetry to Predict Body Fat in Chilean Adults

“…Likewise; Bell and McClure found that BIA equipment would tend to underestimate the TBW content as the body volume of water increased; obtaining on average a difference of 0.7 liters in the TBW estimation as opposed to the deuterium oxide dilution method [24,45]. These differences are also appreciated depending on the ethnic origin of the subjects; Jakicic, Wing and Lang verified that a BIA equation for the population with obesity underestimated FFM in subjects of Caucasian origin in 0.9 to 3.1 kg and, on the contrary, overestimated FFM in African-American subjects In 1.2 to 2.8 kg [46]. As with Deurenberg-Yap, et al they showed that the bioelectrical impedance technique systematically underestimated the percentage of body fat by 3% in both men and women of Asian origin; when using equations developed with a Caucasian population Rush, et al [47,48,14].…”

Fuzzy logic as a decision-making support system for the indication of bariatric surgery based on an index (MAFOI) generated by the association between body fat and body mass index.

“…Hence, the BIA measures the body composition indirectly and is based on the electrical-conductivity principle and its stable relation with the body's liquid. It also uses the resistance, the reactance, and the phase angle as bioelectrical parameters 48,[50][51][52][53][54][55] . Resistance is the opposition offered by the body content to the alternated electrical current and is inversely proportional to the quantity of water and electrolytes present in the tissues.…”

“…The BIA's predictive accuracy can be influenced by the degree of body fat, age, gender, ethnic characteristics, diseases that alter the body type and factors that modify the hydroelectrolytic composition 53 . In order to clarify conflicting results, we used predictive equations that were adequate to the population under study 50,[48][49][50][51][52][53][54][55] .…”

Disparate Body Composition Outcomes for Underwater Weighing, Dual-Energy X-Ray Absorptiometry, and Two Bioelectrical Impedance Devices in Overweight Young Adults

“…Numerous BIA devices have been commercially developed, with the efficacy of these devices in the general population typically being established through comparison to reference measures such as HW and DXA [29]. Currently, there is lack of data validating SF-BIA and MF-BIA performance in overweight or obese individuals using criterion measures such as HW or DXA, with only a handful of published articles presently available [16,30,31].…”