Osteoporosis Screening: The Limitations of Portable Scanners

Lila de Tantillo Health Guide
  • As opportunities to check in on one's bone health with a portable heel or fingertip scanner multiply - at the pharmacy, mall or community center - more people than ever are becoming aware of the risks of osteoporosis. While the devices can help remind individuals to be conscious of the risks of osteoporosis and to take action when needed, there is some controversy over their accuracy and effectiveness in diagnosing bone loss.


    Most physicians agree that these tests, conducted on the extremities, are less informative than Dual Energy X-ray Absorptiometry, often called DEXA or DXA, which is generally performed at the doctor's office, hospital or clinic. A DXA scan measures the bone density in two places - the hip and the spine, the areas where a fracture due to osteoporosis are most likely to cause severe health consequences.

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    "You always like to make your decision after seeing as much of the bones as possible," says Dr. Elana Oberstein, a South Florida rheumatologist. "You need to get the real deal."


    It is important to understand both the benefits and limitations of the heel and finger tests, which are quick, painless, and cheap. You can get a sense of how your bone mass is doing and an idea about your risk of a possible fracture. However, there is a limited amount of research proving the relationship of such a scan to overall bone health.


    One reason for this is that the composition of the bone in the heel and the finger is different from that of your hip and spine. According to Dr. Oberstein, almost all the bone in the body consists of the dense cortical bone and the porous trabecular bone. The proportion of the two types of bones is not identical throughout the skeleton. For example, the heel has a lower percentage of cortical bone and more trabecular bone in comparison to the hip or spine. For this reason, a scan conducted in this area will not provide an exact equivalent of what is going on in the areas considered most revelant to osteoporosis.


    Another factor to keep in mind is that the body parts generally tested by portable scanners are largely irrelevant to drug therapy for osteoporosis. Just about all medicines to improve bone density - including bisphosphonates such as Fosamax and hormones such as Forteo - have been tested and approved for their ability to reduce the risk of hip and spine fractures, not those of the heel or fingertip, Dr. Oberstein notes.


    Of course, a DXA scan by itself won't do anything to help strengthen your bones. But a recent study in the Journal of Aging and Health found that women who received DXA scans were significantly more likely to take their calcium and were more aware of their susceptibility to osteoporosis than those in a control group. Perhaps the detailed information gleaned from their scan helped empower the women to take charge of their bone health. If you are at risk of bone loss, talk to your doctor about whether undergoing a DXA scan might be part of a comprehensive plan to prevent osteoporosis.

Published On: September 28, 2007