Osteosarcopenia is a geriatric musculoskeletal syndrome characterized by co-existence of osteoporosis and sarcopenia (low skeletal muscle mass, strength, and/or functional capacity). There is strong evidence of overlap between the pathophysiology of osteoporosis and sarcopenia (muscle-bone crosstalk). This research plan will further explore the relationship between bone and muscle, and provide new information about effect of osteoporosis medications on muscle health in older adults who are under treatment for osteoporosis.

Inclusion Criteria:

Ambulatory adults age ≥65 years including those using assistive devices to maximize generalizability, if they have criteria for treating osteoporosis including:

1. Osteoporosis by axial bone density (spine, hip or forearm BMD T-score ≤-2.5 SD) or
2. A previous adult fragility fracture of the spine or hip or
3. Would be treated based on FRAX National Osteoporosis Foundation treatment thresholds of a 10-year risk of ≥ 20% for a major osteoporotic fracture or ≥ 3% for hip fracture using femoral neck BMD.

Exclusion Criteria:

1. Patients with a calculated creatinine clearance < 35 ml/min or
2. Who have a contraindication for bisphosphonates or denosumab or
3. Those who are scheduled for a tooth extraction to avoid jaw osteonecrosis or
4. Subjects with severe liver disease or
5. Those who have been on oral bisphosphonates for the past 1 year and intravenous bisphosphonates for the past 2 years prior to the study or
6. Men