Inclusion Criteria:

• Ambulatory postmenopausal women
• Received denosumab and completed study 20050179, completed study 20050141, completed study 20060237, completed study 20030216 but did not enroll in study 20060289. Subjects who will participate in the off-treatment imaging study for 20080747 also are eligible.
• Completed participation in eligible studies (4.1.2) ≥ 12 and ≤ 36 months prior to screening
• Provide signed informed consent

Exclusion Criteria:

• Did not receive denosumab in studies 20050141, 20060237, 20030216, or 20050179.
• Discontinued investigational product before end of study visit for studies 20050141, 20060237, 20030216, or 20050179.
• Received > 1 month osteoporosis treatment since having completed studies 20050141, 20060237, 20030216, or 20050179.
• Received zoledronic acid at any time after ending study participation in parent studies 20050141, 20050179, 20030216, or 20060237.
• Subjects newly diagnosed with any of the following conditions during the intervening period since completing studies 20050141, 20060237, 20030216, or 20050179:
• Hyperthyroidism (stable on anti-thyroid therapy or post-ablation is allowed, if the Thyroid Stimulating Hormone is within the normal range)
• Hypothyroidism (stable on thyroid replacement therapy is allowed, if the Thyroid Stimulating Hormone is within the normal range)
• Hyper- or hypoparathyroidism
• Osteomalacia
• Paget's disease of bone
• Other bone diseases which affect bone metabolism (eg, osteopetrosis, osteogenesis imperfecta)
• Malignancy within the last 5 years (except cervical carcinoma in situ or basal cell carcinoma).
• Self-reported alcohol or drug abuse within the previous 12 months.
• Permanently non-ambulatory subjects (use of assistive device eg cane, walker is permitted).
• Subject has known or suspected sensitivity or contraindication to tetracycline derivatives.
• Received any investigational product other than denosumab.
• Current use of the following osteoporosis agents: bisphosphonates, calcitonin, fluoride, parathyroid hormone analogue, selective estrogen receptor modulators, systemic oral or transdermal estrogen (except vaginal preparations and estrogen creams which are acceptable), strontium or tibolone.
• Has undergone bilateral transiliac crest bone biopsy in the past.
• Current use of medications that, in the opinion of the investigator, cannot be discontinued and may compromise the safety of the subject when undergoing the bone biopsy procedure (eg, aspirin, warfarin, high-dose heparin).
• Current use of systemic glucocorticoid therapy (topical or nasal steroids are permitted).
• Evidence of coagulopathy that in the opinion of the investigator, may compromise patient safety when subjected to the bone biopsy procedure.
• Any disorder that, in the opinion of the investigator, may compromise the ability of the subject to give written informed consent and/or comply with study procedures.