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New Advice About Bone-Density Tests

Do all women in their fifties need a bone-density test? No, but a great many could benefit from knowing how their bones measure up. And at age 65 all women should be tested. This is a change in our recommendation from a few years ago, when we did not advise even women over 65 to be routinely tested.

Osteoporosis is the abnormal thinning of the bone that often accompanies aging. It may lead to fractures and disability or even death; it affects men, too, though usually at more advanced ages. According to a recent survey in the American Journal of Public Health, doctors do a poor job of diagnosing and treating osteoporosis. Up to one-third of all postmenopausal women have osteoporosis, but as few as 2% are ever diagnosed and treated.

Everyone, beginning as early as possible, should take all possible steps to keep bones strong. Regular weight-bearing exercise (brisk walking, weight-lifting, stair-climbing, or physical labor) is essential. So is a good diet, with an emphasis on calcium: low-fat or nonfat dairy products as part of a diet based on fruits, vegetables, and whole grains. Most older women need a calcium supplement to get their intake up to the recommended daily 1,200 to 1,500 milligrams of calcium. As you get older, you may also benefit from supplemental vitamin D, which is essential for bone-building. Many multivitamins contain 400 IU of vitamin D, the recommended daily intake for those age 51 to 70 (those over 70 need 600 to 800 IU). Of course, smokers should quit smoking, and drinkers should keep their intake moderate (at most two drinks daily for a man, one for a woman).

Skeleton keys

There are several ways to measure bone density. The most reliable test is dual energy X-ray absorptiometry (DEXA) of the spine and hip. It is also the most expensive—$250 or more. Similar X-ray tests can be used for the wrist, finger, and heel, at lower cost. You can also have an ultrasound test of your heel for $25 to $35. All of these are good screening tests, though the DEXA of the spine and hip is the gold standard for diagnosis.

Usually the referring physician will decide which kind of test you need. None of these tests is invasive, uncomfortable, or time-consuming. You don't even have to undress. For women over 65, Medicare picks up the tab.

But who really will benefit from testing? The U.S. Preventive Services Task Force (a committee of physicians who review research for the government) does not recommend testing for all women at any age. Even the National Osteoporosis Foundation, a promoter of wider testing, recommends screening for all women only beginning at age 65. If you are doing all you can to keep your bones strong, the chief thing the test can do is help you and your doctor decide whether you should take a bone-preserving drug. The options include bisphos-phonates (Fosamax or Actonel), the hormone-like raloxifene (Evista), or hormones (hormone replacement therapy or calcitonin)—see Wellness Letter, April 2001, for more information.

How do you decide?

If you're a woman under 65, you need a bone-density test only if you are at high risk for osteoporosis (see list below). That includes a lot of women. At menopause, talk with a doctor or other qualified counselor, such as a nurse-practitioner or physician's assistant. It may make sense to wait until you are 65 to be tested.

Gauging your osteoporosis risk factors

• Menopause (or having had your ovaries removed).
• Increasing age.
• Being white or Asian and/or small-framed (weighing 127 pounds or less).
• Having a family history of osteoporosis or hip fracture.
• Having already had a fracture not related to major trauma.
• Being sedentary.
• Smoking.
• Heavy drinking.
• A poor diet, particularly one low in calcium.
• Taking corticosteroids, certain anticonvulsants, or excess doses of thyroid hormones for long periods.