A technique to assess body composition and sarcopenia using DXA: application for an obese population

The objective of this study was to explore the accuracy of summing multiple dual-energy X-ray absorptiometry (DXA) scans to estimate whole-body soft tissue measures and the sarcopenic index in female subjects for application to an obese population. Forty-five women who fit within the DXA scanning region (M+/-s.d.; BMI=24.5+/-4.6 kg/m(2)) were scanned four times (one normal whole body (WB) scan, one head/trunk/leg scan allowing trunk delineation (TRK-H-L), one scan with body shifted right (LA) and one left (RA) to allow arm delineation). Fat mass (FM) and appendicular lean mass were determined from the WB scan (aLM(WB)), with the latter determined by summing arm and leg mineral-free lean mass (MFLM). Strong agreement and no differences (M+/-s.d.(DIFF)) were found between FM(WB) and FM(SUM) (-0.12+/-0.38 kg, P=0.37; r=0.999, P<0.001); MFLM(WB) and MFLM(SUM) (0.02+/-0.36 kg, P=0.80; r=0.998, P<0.001); and aLM(WB) and aLM(SUM) (0.12+/-0.32 kg, P=0.63; r=0.994, P<0.001). Summing DXA scans is a valid method for determining the risk for sarcopenic obesity and may aid research regarding obesity and risk for disability.