Project 176104

Clinical trials have shown that teriparatide, a bone formation drug, increases bone mineral density (BMD) at the lumbar spine and total hip, but decreases BMD at the forearm after 20 months of therapy. It is unclear whether this decrease in BMD at the forearm is because of bone growth with resulting increased bone mass and no change in bone mineral content (which will increase bone strength and decrease fracture risk) or whether teriparatide therapy is site-specific and has a negative effect at the forearm. Currently, there is a new technology, high resolution pQCT (HR-pQCT) that can assess bone geometry without a biopsy. Since bone strength is affected both by BMD and bone structure (as well as other material properties), our group is interested in examining changes in bone geometry at the forearm and ankle in postmenopausal women with osteoporosis who receives 18 months of teriparatide therapy. We believe that this new approach of measuring bone strength will help us better understand whether teriparatide has different effects at different bone sites. In addition, measuring different aspects of bone strength such as the structural properties of bone (size and shape, and geometry) and the material composition (bone mineral content or BMD) will increase our understanding of the mechanisms of teriparatide treatment at different bone sites. In the end, this data will help clinicians explain the pros and cons of this therapy to their postmenopausal patients with osteoporosis.