Osteoporosis is characterized by reduced bone mass and bone strength leading to an increased risk of fractures. Although health care professionals have long known that low bone mineral density (BMD) is an important risk factor for bone fractures, questions have remained about how often BMD should be measured.

Scientists at the Institute for Aging Research at Hebrew SeniorLife in Boston sought to determine whether changes in BMD over a four-year period (from baseline) provided useful information regarding fracture risk. The study, published in the Journal of the American Medical Association, was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), the National Institute on Aging (NIA), and the National Heart, Lung, and Blood Institute (NHLBI), all part of the NIH.