The most important message of the study," said Jane Cauley, a nurse and professor of epidemiology at the University of Pitts-burgh and a coauthor of the study, "is determining when an elderly woman needs a second bone mineral density scan." Primary care providers and obstetrician- gynecologists order most DXA scans, as do advanced practice nurses working in these specialties. They can apply the new results to avoid ordering unnecessary scans. However, should an older woman with normal bone density develop a chronic condition that requires high doses of corticosteroids, which rapidly degrade bone density, "then you'd want to repeat bone scans sooner," cautioned Cauley. She also pointed out that in the study the interval to osteoporosis did shrink with increasing age.-Carol Potera