Lean body mass assessment by Dual-energy X-ray absorptiometry and the method of Hume

Dual-energy X-ray absorptiometry (DXA) as a gold standard of body composition assessment enables development and calibration of the anthropometric equations in estimation of the body composition, as well as the lean body mass (LBM). Lean body mass can be calculated from height and weight using the method of Hume. The aim of this study was to discover the accuracy of the Hume's equation in determining LBM. DXA was performed in 88 women with mean BMI (28.22±5.12 kg/m2), divided in 4 groups according to their BMI: 1st gr.<25 kg/m2; 2nd gr. 25-29,9 kg/m2; 3rd gr. 30-34,9 kg/m2; and 4th gr. 35-40 kg/m2. Hume's equation calculated LBM (kg), LBM = a0.29569 x (body weight in kg)o + a(0.41813 x (height in cm)o - 43.2933, and it was compared to the LBM values determined by DXA. Mean lean body mass determined by the method of Hume was 49.42±3.68 kg, and it was significantly higher compared to the mean lean body mass (40.59±4.5 kg) determined by DXA (p<0.0001). The lean body mass values determined by the method of Hume in the 1st group (41.81±4.1 kg), in the 2nd group (43.53±3.69 kg), in the 3rd group (46.74±3.69 kg) and in the 4th group (46.74±4.26 kg) were significantly higher compared to the correspondent LBM values determined by DXA (37.96±4.06 kg) in the 1st group (p<0.001), (39.25±2.95 kg) in the 2nd group (p<0.0001), (43.1±3.93 kg) in the 3rd group (p<0.005) and (46.11±3.07 kg) in the 4th group (p<0.042). BMI increase was associated with significant LBM increase in the 3rd and 4th group compared to the 1st gr. Hume's equation overestimated lean body mass compared to DXA, and it couldn't be used for lean body mass assessment in clinical practice.