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Osteoporosis Screening

(Revised September 2002)

Osteoporosis (bone thinning) and resulting fractures (especially of the spine, hip, and forearm) is a huge problem in the United States. Bone mass reaches its peak in early adulthood; thereafter, it remains steady until the menopause in women. During the first five to ten years after the menopause, women can lose 1 to 2 percent of bone strength in long bones(such as the hip) and double that in the bones of the vertebrae (spine) each year. Women are very susceptible to vertebral fractures between ages 50 and 70.

Both women and men show additional bone loss starting in the mid 50s. This type of bone strength loss, incorrectly called senile osteoporosis, continues at a slow pace for the rest of the men's or women's lives, leading to a marked increase in risk for fractures of the hip and wrist. Women have the greater problem because they have two risk factors - the loss occurring during the aging process and the loss imposed by reduction in estrogen hormones after the menopause. In the first five to ten years after the menopause, they lose an average of 2 percent of bone mass each year (as a consequence of reduction in hormone levels). After that period, it settles down to an average 1 percent per year loss.

Some 15 to 20 percent of white women over the age of 50 suffer from osteoporosis. The percentage among black women is considerably less. About 40 percent of white women and 14 percent of black women will experience a bone fracture after age 50; two-thirds of those fractures will occur after age 75. About one-third of the fractures will involve the hip. That is the most dangerous site; not infrequently, its consequences can be life threatening. Men, too, suffer from osteoporosis, but far less frequently; their osteoporosis frequency and fracture rate is about one-third that found in women.

The cost of osteoporotic fractures is huge - in the range of $20 billion a year.

The ideal approach would seem to be early detection so osteoporosis can be treated and, better still, prevented. We have the technology to detect moderate bone loss (called osteopenia) and more severe loss (frank osteoporosis). The most accepted test is an x-ray technique called dual-energy absorptiometry. Bone mass is compared to that of healthy younger women and is recorded as standard deviations below the average of younger women - 1 to 2.4 standard deviations below is osteopenia; 2.5 or more standard deviations below is osteoporosis. Most often, the hip alone or the hip and spine are studied, but the forearm can be examined as can the heel. In addition to the 15 to 20 percent of women over age 50 who have osteoporosis, another 30 percent will be found to have osteopenia.

The big question is whom to screen and when. Quite recently, Healthful Life decided to recommend bone density screening a few years after the menopause to detect women who lose bone mass particularly rapidly and once again after age 60 to detect women with osteoporosis or osteopenia.

It seemed to make sense to try and prevent osteoporosis or catch it early. But, there are several vexing and unsettled issues that have caused us to re-evaluate that recommendation.

If a woman is osteopenic, it is also not clear when she should have additional bone density tests.

If a woman has osteoporosis on bone density testing, we have drugs that can reduce fracture rate by at least 30 percent. The drugs of choice are alendronate (Fosamax), risedronate (Actonel), and probably raloxifene (Evista). Estrogens are not recommended. Some of these drugs (the bisphosphonates, such as Fosamax and Actonel) reduce fracture rates within 12 to 18 months after starting treatment. It is not clear whether the mechanism of action is building bone mass; there are other possible mechanisms. These drugs are new and have been studied for, at most, seven years; it is possible there could be some adverse effects on bone strength with longer treatment.

Bone density testing, if utilized by a large percentage of postmenopausal women, would be enormously expensive. Although determining heel bone density is a less expensive test, the evidence suggests that it is not a reliable indicator of hip bone strength. It is the hip fracture that is most worrisome and most dangerous after age 60. So, the test used would have to be the more expensive bone density test of the hip.

In summary, if a woman has osteoporosis, we have medications that will be somewhat effective. We do not have proven medications for osteopenic women, we do not know what percentage of osteopenic women will go on to osteoporosis, and we do not know how often follow up bone density tests should be done.

What then would be sensible recommendations based on our current knowledge?

And, of course, everyone should follow the general recommendations:

At present, no screening tests are recommended for men, but it is likely such tests will eventually be recommended for men between ages 60 and 70. For now, men should follow the general recommendations.

Those are our recommendations for the present. As more data become available, we will be prepared to modify these recommendations in accord with the new evidence.