New bioimpedance analysis system: improved phenotyping with whole-body analysis

Abstract

Objective: Bioimpedance analysis (BIA) is a potential field and clinical method for evaluating skeletal muscle mass (SM) and %fat. A new BIA system has 8-(two on each hand and foot) rather than 4-contact electrodes allowing for rapid 'whole-body' and regional body composition evaluation. Design: This study evaluated the 50 kHz BC-418 8-contact electrode and TBF-310 4-contact electrode foot-foot BIA systems (Tanita Corp., Tokyo, Japan). Subjects: There were 40 subject evaluations in males (n ¼ 20) and females (n ¼ 20) ranging in age from 6 to 64 y. BIA was evaluated in each subject and compared to reference lean soft-tissue (LST) and %fat estimates in the appendages and remainder (trunk þ head) provided by dual-energy X-ray absorptiometry (DXA). Appendicular LST (ALST) estimates from both BIA and DXA were used to derive total body SM mass. Results: The highest correlation between total body LST by DXA and impedance index (Ht 2 /Z) by BC-418 was for the foot-hand segments (r ¼ 0.986; left side only) compared to the arm (r ¼ 0.970-0.979) and leg segments (r ¼ 0.942-0.957)(all Po0.001).The within-and between-day coefficient of variation for %fat and ALST evaluated in five subjects was o1% and B1-3.7%, respectively. The correlations between 8-electrode predicted and DXA appendicular (arms, legs, total) and trunk þ head LST were strong and highly significant (all rX0.95, Po0.001) and group means did not differ across methods. Skeletal muscle mass calculated (Kim equation) from total ALST by DXA (X7s.d.)(23.779.7 kg) was not significantly different and highly correlated with BC-418 estimates (25.279.6 kg; r ¼ 0.96, Po0.001). There was a good correlation between total body %fat by 8-electrode BIA vs DXA (r ¼ 0.87, Po0.001) that exceeded the corresponding association with 4-electrode BIA (r ¼ 0.82, Po0.001). Group mean segmental %fat estimates from BC-418 did not differ significantly from corresponding DXA estimates. No betweenmethod bias was detected in the whole body, ALST, and skeletal muscle analyses. Conclusions:The new 8-electrode BIA system offers an important new opportunity of evaluating SM in research and clinical settings. The additional electrodes of the new BIA system also improve the association with DXA %fat estimates over those provided by the conventional foot-foot BIA.

Body fat reference curves for children

“…The impedance scales used in this study has been validated against DXA in mixed populations of children and adults and found to be superior to previous BIA methods. 10 More recently a pediatric validation of the BC-418MA model against DXA and air-displacement plethysmography (BodPod) has been performed. 11 In samples of 45 boys (age 11.073.6 year) and 34 girls (age 11.073.0 year) results were highly correlated with DXA (r ¼ 0.91, SEE ¼ 4.46%) and mean values did not differ significantly.…”

Four-week pedometer-determined activity patterns in normal weight and overweight UK adults

“…Percent body fat measured using the Tanita BC-418 has been shown to correlate highly with the reference measure of dual-energy X-ray absorptiometry. 12 As impedance fluctuates with the distribution of body fluid, to improve accuracy, participants were required to urinate before the measurement of percentage body fat was taken. Measurements of weight, BMI and body fat were repeated at the end of the study.…”

The effect of acute fluid consumption on measures of impedance and percent body fat estimated using segmental bioelectrical impedance analysis

“…Arms were held in the straight down position without touching their sides. As previously described (Pietrobelli et al, 2004), the SBIA system consists of four contact electrodes (two anterior and two posterior) that are mounted on the surface of a platform scale and each extremity handgrip has an anterior and posterior electrode. All measurements are carried out using a constant singlefrequency current (50 kHz, 500 mA).…”

“…These contact-electrode analyzers, which measure impedance as a participant stands on a scale-like platform, differ significantly from the traditional BIA method that requires the accurate placement of gel electrodes at specific anatomical locations. LBIA and SBIA have been found to have overall performance characteristics for impedance measurement and body composition analysis similar to traditional BIA while offering the advantage of increased speed and ease of measurement (Nunez et al, 1997;Pietrobelli et al, 2004).…”