It's easy to take your bones for granted — especially since they're built to withstand tiny fractures, often without causing symptoms. But such "silent" fractures should not go unnoticed — or untreated — according to new research published this week in the Journal of the American Medical Association. In one of the largest studies to investigate the bone-weakening disease of osteoporosis, University of Pittsburgh scientists report that a commonly used bone density test can effectively screen for the disease and predict women's likelihood of developing spinal fractures — the most typical osteoporosis-related fracture — up to 15 years in advance.
, a professor of epidemiology
at the University of Pittsburgh Graduate School of Public Health
, has been analyzing the bone health of 2,300 women over age 65 since 1986. Doctors have long known that low bone density increases the risk of osteoporosis and fractures, but until now, no study has ever documented the extent of the risk long-term. In their 15-year study, Cauley
and her team found that women who had low bone density and a previous spinal fracture at baseline had a 56% chance of developing an additional fracture during the course of the study; women with normal bone density and no previous fractures had a significantly lower risk, of 9%. What's more, Cauley says
, "We found that a single bone density measurement accurately predicted the likelihood of who would have a spine fracture within a 15-year period."
"We've sort of known that low bone density increases risk of fractures, but the beauty of this study is that it is one more solid piece of evidence from a large, [placebo-]controlled and highly respected trial that locks it in," says Dr. Ethel Siris, professor of medicine at Columbia University and president of the National Osteoporosis Foundation.
Ten million Americans over 50 suffer from osteoporosis, and one and a half million develop fractures as a result of their disease. The bone mineral density test uses low doses of X-rays to measure the amount of crucial bone minerals, such as calcium, in key parts of the skeleton such as the spine and hips (some tests can test density in the knees and fingers). The scan detects osteoporosis or the risk of developing it, but it also doubles as a fracture finder, since it has the ability to take simple pictures of the spine that can reveal tiny cracks. And the early detection of such tiny, silent fractures is critical to preventing more serious damage to bones later. "So many spine fractures are in fact silent," notes Siris. "But if you have a fracture and don't know it, you're at greater risk of more fractures in the future." In fact, she says, the dowager's hump that afflicts many elderly women is the result of multiple, accumulated fractures to the vertebrae.
By identifying such lesions early with the bone density test, we "shouldn't be seeing women with the dowager's hump anymore," says Cauley. The earlier spine fractures are diagnosed, the earlier they can be treated — before they compromise the shape of the spine or lead to debilitation. There are several FDA approved medications available for preventing or treating bone loss, including the bisphosphonates such as Fosamax, Boniva, Actonel and the once-yearly injectable Reclast. And since a single screen can predict disease so far in advance, say experts, there's no excuse for women over 65 not to get the test. Medicare even covers the cost of the screening — but currently only 20% of eligible Medicare patients actually get a<