Assessment of Mineral and Bone Disorders in Kidney Transplant Recipients

Inclusion Criteria: 1. HD group: Patients undergoing HD for at least 12 months, aged 20-70 years, after signing an informed consent. 2. KTR group: Patients with successful KTx performed at least 12 months prior to their enrollment, aged 20-70 years old, after signing an informed consent. Subjects will be eligible for inclusion regardless of KTx immunosuppression regimen, pre-transplantation history, history of pre-transplant dialysis, or whether the kidney donation was from a living or deceased donor. 3. GPO group: men and postmenopausal women diagnosed with primary osteopenia or osteoporosis, aged 50-70 years old, after signing an informed consent. Exclusion Criteria: 1. HD group: Treatment with active bone therapies (excluding calcium and vitamin D); ongoing cancer treatment or recent history of malignancy, cirrhosis, recent major fractures, patients who have received transplants other than kidney, secondary causes of osteoporosis (other than CKD or transplant-related: primary hyperparathyroidism, hyperthyroidism, congenital bone disorders, sarcoidosis, severe bone trauma, malignant tumors, inflammatory bowel disease, endogenous Cushing syndrome, anti-estrogen/anti-androgen therapy, and anorexia nervosa), pregnancy and breast-feeding. 2. KTR group: The same as for HD + return to dialysis + acute graft rejection. 3. GPO group: The same as for HD + diabetes mellitus + prolonged glucocorticoid therapy (\>7.5 mg Prednisone or equivalent for at least 3 months).