There are no procedures or changes to the routine clinical management of patients participating in the study. Baseline characteristics will be described for patients enrolling in both waves 1 and 2. Patients enrolling in wave 1 will be followed for approximately 30 months from the date of first injection in the study. It is anticipated that patients will return to the site. Clinical information obtained for routine clinical practice will be recorded where available, including Prolia administration, previous and current therapies, medical history (including fracture), ADRs, SADRs and co-morbidities.The study is descriptive in nature, and no formal hypothesis will be tested. In general, data summaries will be presented by wave and by subgroups of interest.