Healthy Living News

Women May Need Fewer Bone Tests

by Robert H. Shmerling, M.D.
Harvard Medical School

Older women at low risk of osteoporosis may need to get bone density tests only every 15 years, new research suggests. The study included 5,000 women. They were part of a large, long-term health study. When the study began, they were at least 67 years old. A bone mineral density test at that time showed that none had osteoporosis. Some did have osteopenia. They had below-normal bone density, but not as low as in osteoporosis. During the next 15 years, only 1% of those with normal bone density developed osteoporosis. But the number was 62% for those with advanced osteopenia. Women who had normal bone density or mild osteopenia were found to be low-risk. Researchers concluded that most could wait 15 years for another test. Some might need the tests more often if other factors increased their risk. Women with moderate osteopenia should repeat the test in 5 years, researchers said. Those with advanced osteopenia should get the test every year. The New England Journal of Medicine published the study. The Associated Press wrote about it January 19.

What Is the Doctor's Reaction?

Most screening tests are not a one-time thing. Even if your test results are perfectly normal, you’re probably going to be told to have the test again in a while.

For example, if you have a mammogram, it's likely you'll need another in a year or two. If you have a colonoscopy, they'll probably tell you to have another in 10 years. The same is true for cholesterol tests, prostate cancer screening and Pap smears. And if the results are abnormal, you're probably in for even more frequent tests.

What about the bone mineral density (BMD) test? This is a test for osteoporosis. People with this condition have fragile bones that are prone to fracture. These fractures, especially hip fractures, can lead to loss of independence and even death. But osteoporosis often can be prevented. Effective treatments also exist. So the results of a bone mineral density test are important. It's easy to understand why current guidelines recommend routine testing for women over age 65 and men age 75.

How often should the tests be repeated? According to the National Guideline Clearinghouse, "there is overall agreement that an interval of at least two years is appropriate" for repeat testing. In fact, the ideal number of years between tests is not clear.

The authors of a new study wondered whether doing frequent tests made sense. They asked a simple question: Can bone mineral density tests predict how long it will take for 10% of women to develop osteoporosis? If the answer is "yes," one can propose a rational standard for how often to do repeat testing.

The New England Journal of Medicine published the study. The researchers looked at records for nearly 5,000 women. Some of them had normal bone density when the study began. The rest had osteopenia, a condition in which bone density is low but not low enough to be considered osteoporosis. None of the women had any previous fractures related to osteoporosis. All were at least age 67.

This study found that women should schedule repeat bone mineral density tests based on the results from their last test:

• Every 15 years if test results are normal or show mild osteopenia. Fewer than 1% of women with normal results and 5% of women with mild osteopenia developed osteoporosis within 15 years.
• Every 5 years for women with moderate osteopenia
• Yearly if a test reveals severe osteopenia

Women were divided into mild, moderate and severe osteopenia groups based on their test result (called the T score).

The results of this study have the potential to change how we screen for osteoporosis. After all, there's little reason to order a test over and over if the result is unlikely to matter. And limiting tests that aren't needed could provide enormous savings in wasted health care costs.

Still, it's worth keeping in mind some cautions about this research.

• Bone mineral density is not a perfect screening test. Some people develop "fragility fractures" even though their test result is normal or shows osteopenia.



• Many doctors recommend treatment for a woman whose bone mineral density is falling fast, even if she doesn't yet have osteoporosis. An example would be a woman who had mild osteopenia a few years ago and now has severe osteopenia. Waiting for osteoporosis to develop may be waiting too long.



• For women with high risk of osteoporosis, bone density may change quickly. This study tried to account for factors that could affect bone mineral density. But other factors could have been missed. This could make the results less accurate.



• This study did not include men. The ideal interval to repeat testing for men remains uncertain.

Still, if you've ever wondered whether you really needed that repeat bone test, this new study suggests you're on to something.

What Changes Can I Make Now?

Talk to your doctor about any factors that may affect your personal risk of osteoporosis. Ask about what screening tests, if any, you should have. Review this new study with your doctor if you are having repeated bone mineral density tests.

Know the factors that increase the risk of osteoporosis. While family history is an important one, it cannot be changed. Other factors can be changed. They include:

• Lack of exercise
• Lack of calcium or vitamin D in the diet
• Smoking
• Drinking excess amounts of alcohol
• Certain medicines, especially corticosteroids (but don't change your medicines without the approval of your doctors)
• An overactive thyroid (detectable by a simple blood test)

If your doctor recommends a medicine to prevent or treat osteoporosis, take it as prescribed. If you have side effects or other concerns about taking it, be sure to review this with your doctor.

What Can I Expect Looking to the Future?

Current guidelines recommend several screening tests for common, treatable conditions. However, it's important to review them to be sure they make sense. This study is a good example. Bone mineral density tests are important. But, for many women, repeating them often may not be.

Categories: Women's Health

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