Device‐Specific Sex‐ and Age‐Stratified Distributions of Phase Angle and Skeletal Muscle Mass in a Routine Outpatient Multifrequency Bioelectrical Impedance Cohort
D. E. Cortés Sierra, J. M. Mora‐Méndez, R. Rosero‐ReveloABSTRACT
Background
Large population‐based studies have demonstrated age‐ and sex‐related differences in phase angle (PhA). However, multifrequency bioelectrical impedance analysis (BIA) systems remain highly device‐specific due to proprietary algorithms and prediction equations. This limits comparability across platforms, making descriptive distributions from single‐device cohorts essential for routine clinical interpretation.
Objective
To describe sex‐ and age‐specific distributions of PhA and skeletal muscle mass using a single multifrequency BIA platform in an outpatient cohort, and to explore relationships with other device‐derived body composition estimates.
Methods
A retrospective cross‐sectional analysis was conducted on adults in an outpatient program using the SECA mBCA 514 platform. PhA and skeletal muscle mass data were available for 1849 and 1870 participants, respectively. Sex‐ and age‐stratified percentiles were generated. Fat‐to‐muscle ratio (FMR) was calculated, and its associations with PhA and device‐estimated visceral adiposity were evaluated using Spearman correlation.
Results
Men demonstrated higher PhA and skeletal muscle mass values than women; both measures declined across age strata in both sexes. Women exhibited higher FMR values. Higher FMR was moderately associated with lower PhA (rho = −0.467, p < 0.001), while its association with device‐estimated visceral adiposity was weak (rho = 0.104, p < 0.001). Since all measurements originated from the same platform, these associations are descriptive rather than mechanistic.
Conclusions
Device‐specific, stratified distributions derived from routine multifrequency BIA assessments assist the clinical contextual interpretation of outpatient body composition measurements. The observed relationships between FMR and PhA are hypothesis‐generating and require further validation using independent gold‐standard reference methods such as MRI, DXA, or CT.