Appendicular skeletal muscle mass: prediction from multiple frequency segmental bioimpedance analysis

Abstract

Objectives: Bioimpedance analysis (BIA) methods have potential to predict appendicular skeletal muscle mass (SM), although available 50 kHz prediction models include, in addition to impedance (Z), an independent age term. An age term in models is undesirable as it re¯ects incomplete understanding of underlying conduction physiology. This study tested the hypothesis, based on¯uid distribution models related to aging, that appendicular SM bioimpedance analysis (BIA) prediction models would no longer include an independent age term, after ®rst controlling for stature-adjusted appendicular impedance (height 2 aZ), at injected frequencies greater than 50 kHz. Design: Cross-sectional evaluation of adults who had segmental Z and phase angle (f) measured with multiple frequency BIA, and arm and leg SM with dual-energy X-ray absorptiometry (DXA). Skeletal muscle prediction models were developed with appendicular SM as dependent variable and height 2 aZ, gender, age and f as potential independent variables. Results: Examination of hypothesis in 49 subjects indicated: both arm and leg SM were highly correlated with height 2 asegmental Z at frequencies ranging from 1 ± 300 kHz; gender was signi®cant covariate in prediction models only at 1 kHz; age remained a signi®cant covariate after controlling for height 2 asegmental Z at all frequencies; f did not add signi®cantly to models; and SM prediction models gave maximum R 2 at 50 kHz for arm but R 2 continued to rise up to 300 kHz for leg. Conclusion: Although multifrequency BIA did not eliminate SM prediction model age term, our ®ndings suggest injected frequencies up to 300 kHz may have advantages for evaluating leg SM over conventional 50 kHz method.

Compatibility of different methods for the measurement of visceral fat in different body mass index strata

“…Body weight is also measured in the leg-to-leg pressure contact BIA; in addition to providing information on fat mass, multifrequency BIA (frequencies up to 300 kHz) may have an added advantage over SF-BIA (50 kHz) for evaluating leg skeletal muscle (25,26). Martinolli et al reported that multi-frequency BIA seems to be a more accurate method than single frequency BIA for estimating the TBW compartment of healthy and obese adults (27).…”

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

“…A strong correlation is present between appendicular resistance or impedance and ALST (Pietrobelli et al, 1998a). Adjusting measured resistance/impedance for either limb length or height then allows development of BIA ALST prediction equations.…”

“…The opportunity to estimate segmental electrical properties offers the opportunity to estimate appendicular lean soft tissue (ALST), mainly skeletal muscle (Pietrobelli et al, 1998a). A strong correlation is present between appendicular resistance or impedance and ALST (Pietrobelli et al, 1998a).…”

Accuracy of eight-polar bioelectrical impedance analysis for the assessment of total and appendicular body composition in peritoneal dialysis patients

“…In healthy subjects, segmental BIA has been shown to offer accurate estimates of appendicular body composition (Pietrobelli et al, 1998(Pietrobelli et al, , 2004Malavolti et al, 2003). However, segmental BIA has never been evaluated for the assessment of appendicular muscle mass in PD patients.…”