Computed tomography
A 64-slice computed tomography scanner (Somatom Sensation 64 CT system, Siemens Corp., Germany) was used for abdominal CT scans. Data were analyzed using Syngo CT2005A software. Each participant lay in the center of the CT scanner while the abdominal segment of 2–5 lumbar vertebrae was measured. The main scanning parameters of CT measurement were set as X-ray tube voltage: 120Kv, a tube current of 120 mAs, X-ray beam width of 1.5 mm, scanning time was 0.5 s, slice thickness was 5 mm, slice increment was 2mm, image reconstruction kernel index was B20. Two image analysts (observers) were trained by radiologists in human anatomy associated with the region of the L3-L4 lumbar spine. A fixed image analysis program was used to calculate fat, and CSA of the psoas major at L3-L4. Image processing software Slice-O-Matic version 4.3 (Tomovision, Magog, QC, Canada) was used, and the image analysis program Slice-O-Matic [