Bisphosphonates are sometimes used to treat osteoporosis. Studies have shown that the risk for bone fractures lessens when women with low bone mineral density take these medications for between one and four years. However, little is known about whether taking bisphosphonates for longer has the same effect. A team of researchers examined whether older women taking bisphosphonates for 10-13 years had fewer bone fractures than older women with similar fracture risks who took these medicines only briefly.