 Study design We will compare geometric and BMD parameters at the proximal femur in women with PFF and in age-matched women without PFF. This is a multicenter case-control study with direct individual benefit. A diagnostic benefit exists for both the cases and the controls, who will undergo a thorough physical evaluation including routine screening for factors suggesting secondary osteoporosis, BMD measurements, and identification of risk factors for fractures e.g., impaired balance to allow planning of appropriate primary prevention controls or secondary prevention cases. The therapeutic benefit will lie in advice regarding diet and lifestyle, calcium and vitamin D supplementation, and bisphosphonate therapy, as indicated by bone mass measurement results. 