Agreement between bioimpedance analysis and ultrasound scanning in body composition assessment

Objectives: This study aimed at evaluating the agreement between bioelectrical impedance analysis (BIA) using ABC-02 Medas and A-mode ultrasound (AUS) using BodyMetrix™ BX2000 for fat mass (FM), fat free mass (FFM), and body fat percentage (%BF) in females.

Methods: The cross-sectional, single-center, observational study was performed in 206 female subjects aged 18-67 years. The examination program included measurements of body height and weight along with waist, hip circumferences, and body composition analysis. The measurements were performed by ultrasound scanner and bioimpedance analyzer.

Results: We found that 20.9% of women were obese based on BMI (≥30 kg/m²), which was significantly lower when using a criterion based on body fat percentage (%BF ≥ 30%) measured with US (53.4%, p = .0056) or BIA (54.8%, p = .0051). At the group level, both methods were found interchangeable and showed practically negligible differences (0.1% for %BF, 0.5 kg for FM, and 0.4 kg for FFM). Agreement analysis conducted in the whole sample revealed a low level of agreement in estimating %BF (CCC = _0.72 0.77 _0.82) and FFM (CCC = _0.81 0.84 _0.86), and medium level of agreement in estimating FM (CCC = _0.91 0.93 _0.94). The level of agreement in estimating %BF and FFM was improved to the medium level with the use of newly generated prediction equations.

Conclusion: Thus, the proposed equations can be used for conversion of body composition results obtained by AUS into the BIA data.