Assessment of Bone Micro-Architecture Using HR-pQCT

Inclusion Criteria: 1. Men 50-85 years old 2. Patients must be willing to undergo a DXA scan. 3. Patients should be willing to undergo HRpQCT scan of the radius and tibia. Exclusion Criteria: 1. Inability to tolerate CT scans 2. Use of medications known to impact bone and mineral metabolism: * use of a bisphosphonate or teriparatide in the last year or for \>12 months ever; * current calcitonin; * prednisone \>5 mg daily or the equivalent glucocorticoid for \>10 days in the last 3 months; * current testosterone therapy; * current thiazolidinedione (TZD); * current androgen deprivation therapy; * current use of an antiepileptic agent that alters hepatic vitamin D clearance; * use of thyroid hormone replacement with current thyroid stimulating hormone \<0.1 mIU/L 3. Disease known to affect bone (e.g., primary hyperparathyroidism, Pagets disease, clinically significant liver disease) 4. Illicit drug use or alcohol use \>3 drinks/day 5. Serum calcium \>10.2 mg/dL or calculated creatinine clearance \<30 mL/min 6. Weight \>350 pounds (the maximum weight limit of the DXA) 7. Hardware in the lumbar spine 8. History of bilateral hip replacement, or bilateral wrist or ankle fracture