Teriparatide (PTH) and Bone Strength in Postmenopausal Women

Plain-language summary

This study will investigate the effects on bone quality of a medication (Teriparatide) used to treat people with severe osteoporosis. Teriparatide is the only bone formation therapy that has been approved for the treatment of postmenopausal osteoporosis in Canada. Osteoporosis is currently diagnosed using a bone mineral density (BMD) scan, which measures the amount of mineral (calcium etc) in bones (the higher the amount of mineral, the lower the fracture risk). Although BMD is linked to bone strength and is used to measure fracture risk, it does not give information on bone structure (called bone geometry) which can also tell us a great deal about fracture risks. Clinical trials have shown that teriparatide increases BMD at the lumbar spine and total hip, while BMD at the forearm decreases after 20 months of therapy. Whether this decrease of BMD at the forearm suggests a higher risk of wrist fracture or a change in bone structure is unclear. Bone biopsies of the pelvis done on people taking teriparatide shows improvement of bone geometry (ie bone thickness and increased trabeculae (small interconnecting rods of bone), suggesting that a change in bone geometry at the wrist may be occurring as well. 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 (a non-weight bearing site) and ankle (a weight bearing site) in postmenopausal women with osteoporosis who receive 24 months of teriparatide therapy. The investigators believe that this new approach of measuring bone strength will help us better understand whether teriparatide has different effects at different bone sites.

Who can participate

What they're measuring

Trial details