Seventy-two postmenopausal volunteers age ≥ 50 years will be recruited from existing databases of ~3500 women with expressed interested in research. All will have normal BMD or osteopenia (T-score > -2.5 at the L1-4 spine, proximal femur and 1/3rd radius) by DXA. Thirty-six will have sustained a "fragility" fracture of the spine, hip or wrist, defined as a fracture occurring with everyday activities including a fall from standing height or less. Historical radiographic documentation of fracture will be obtained. Thirty-six women without fracture will serve as age- race- and BMD-matched controls. Age will be matched to within 6 months; BMD in grams/cm2 at the non-dominant ultra-distal radius will be matched to within 5%.