Agreement between bioimpedance analysis and ultrasound scanning in body composition assessment

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.

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.

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.

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