Aims: 1. To determine whether BMD and muscle mass were associated with fractures and other adverse events in dialysis patients. 2. To explore the effects of the interactions among FGF23, calcium, phosphate, PTH and vitamin D on low bone mineral density and sacropenia in dialysis patients. Method: In this study, the investigators plan to use DXA to screen for BMD, relevant novel bone microstructure parameters, and body composition in chronic dialysis patients. Also, the investigators plan to use blood testing to measure the blood level of FGF23, calcium, phosphate, PTH and vitamin D. The investigators conduct a prospectively follow up program for these participants to evaluate clinical courses and outcomes. Patients will receive DXA (including BMD and body composition) tests and blood work at baseline and one-year. Muscle power and physical performance will be measured at baseline, 6 months and one-year.