Scanning The Skeleton

Yes, you've had a mammogram and a pap smear. You've checked your eight, cholesterol and blood pressure. But if you're a woman over 50, don't head for the door just yet. You have still another test to consider. It's called bone densitrometry, and it could revolutionize women's health care. The quick, painless procedure can reveal signs of osteoporosis-the gradual loss of bone mineral that leaves the skeleton as fragile as fine china--long before symptoms appear. And newly developed treatments can control the process indefinitely. Bone scanners aren't yet a fixture in doctors' offices, and insurers don't always cover the $100 to $250 cost. But as one specialist says, "There's a tidal wave of interest and enthusiasm."

Osteoporosis affects 25 million Americans, mainly postmenopausal women, and the symptoms can be devastating. Studies suggest that a fourth of all women over 60 have experienced spinal-compression fractures, the small vertebral breaks that gradually collapse the spine into a "dowager's hump." Osteoporosis-induced hip fractures, suffered by one woman in seven, now cost $13 billion a year, and that could rise as the baby boomers age.

Until recently, a fracture was often the first sign of trouble. Osteoporosis doesn't show up on conventional X-rays until a fourth or more of a bone's mineral content is gone. But several imaging techniques developed during the 1980s make early detection easy. The most effective--known as DEXA, for dual energy X-ray absorptiometry--can spot even a 1 percent loss. The patient simply lies down for 10 to 15 minutes while a mechanical wand is passed over her body. Doctors can then plot her bone density against population norms or her own past readings.

Watching your bones dissolve would be a useless exercise if nothing could be done about it. But there are now several ways to stop the process. Osteoporosis stems mainly from the loss of estrogen at menopause; replacing it, along with progesterone, costs as little as $25 a month and has other health benefits as well.

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For women who don't like the down-sides of hormone-replacement therapy-renewed menstrual bleeding and a slight increase in the risk of breast and ovarian cancer-there are now two other treatments on the market. Last year the FDA approved alendronate (an oral medication sold under the brand name Fosamax) and calcitonin (a nasal spray sold as Miacalcin). Both products lower the risk of fractures, but Fosamax is especially potent. In a study involving 2,000 osteoporotic women, researchers at the University of California, San Francisco, found that the drug reduced new hip and spinal fractures by half.

Neither of the new treatments is for everyone. Fosamax costs twice as much as estrogen and is far harder to use. It has to be taken first thing in the morning, without food, and can be rough on the throat and stomach. "There have been reports of ulceration and bleeding," says Dr. Marjorie Luckey, a bone specialist at New York's Mt. Sinai Medical Center. Miacalcin is better tolerated, but it costs as much as Fosamax and builds less bone. For women who don't like today's options, there may soon be a fourth. An FDA advisory panel has recommended approval of a slow-release formulation of sodium fluoride (the stuff that protects teeth), and several companies have other drugs in development.

None of the new treatments will reach its potential market until bone scanning becomes more routine, but drug makers are pushing hard to make that happen. Merck & Co., the maker of Fosamax, has helped finance lavish promotions for DEXA devices. And though there are still only 2,200 machines in use nationwide, sales have increased two- to fourfold in the past year.

There are no formal medical guidelines yet on who should take the test. But the best candidates are postmenopausal women who can't or won't take estrogen. Premenopausal women should consider testing if they have a bone-threatening medical condition, such as type I diabetes, rheumatoid arthritis or hyperthyroidism. And some experts favor DEXA tests for thin-boned men over 65. If a person's first test shows no significant bone loss, most doctors suggest waiting four years to run another one. But if the first test signals trouble, yearly follow-ups can help monitor both the condition and the treatment. Widespread testing is a costly proposition-but it may prove cheaper in the long run than an epidemic of shattered bones.

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