VOA慢速英语 SCIENCE IN THE NEWS - Osteoporosis Increases Danger（在线收听）

VOICE ONE:

This is SCIENCE IN THE NEWS, in VOA Special English. I'm Barbara Klein.

VOICE TWO:

And I'm Bob Doughty. Today we tell about osteoporosis, a disease that can make bones weak so they break easily.

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An x-ray of a bone fracture

Osteoporosis is a silent disease until it develops. If you do not know you have it, it can hurt you.

A fifty-five year-old American woman named Jill went skiing several years ago. Although she was a good skier, she fell on a difficult hill. She attempted to get up, but could not move one leg. She was taken to a hospital, where doctors found she had broken a bone in her upper leg. And there was another discovery in the hospital. She had osteoporosis.

Today, Jill still goes skiing. But now she takes medicine to protect against osteoporosis.

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Like Jill, many people do not know they have osteoporosis unless they break a bone. Or, they may find that they are getting shorter.

Osteoporosis can make it hard for a person to stand up straight if the disease is untreated for a long time. When it has progressed very far, walking can be difficult. Severe osteoporosis in older adults can take away their independence.

The National Osteoporosis Foundation works to inform Americans about bone health. The group says breaks caused by weakened bones can lead to pain, disability and even death

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The word osteoporosis means porous bones, or bones that are not solid enough. The disease harms bones by removing calcium and other important minerals from tissue. Bones are living tissue. Tissues continually break down and then they replace themselves. But as people get older, more bone breaks down than gets replaced. The result is that small spaces inside the bone get larger. And the shell of the bones gets thinner.

The National Osteoporosis Foundation, or NOF, says eight of every ten osteoporosis patients are women. It says the condition is most common in Caucasian women over age fifty. Last year, the group suggested that doctors expand their list of persons to watch for osteoporosis. The additions included Latina, African American, Asian and other women. The NOF also called attention to the fact that men can also suffer from osteoporosis.

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Before people develop osteoporosis, they have a condition called osteopenia. Treatment can prevent this condition from becoming osteoporosis. Doctors agree that the best way to deal with osteopenia or osteoporosis is to find and treat it before the disease progresses. Bone damage need not be permanent. Drugs can help replace lost bone.

Identification of osteoporosis and osteopenia is made by measuring the mineral density of a person's bones. In this case, density means the strength of the bones.

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The American Academy of Orthopaedic Surgeons says there are a number of ways bone mineral density can be measured. The group suggests bone mineral density examinations for women sixty years and older. Doctors use the tests to examine the hip and spine, or backbone.

The NOF says a test called Dual-energy X-ray absorptiometry, or DXA, is the best test for osteoporosis. DXA uses radiation from x-rays. The patient does not get much radiation from the process, which lasts only a few minutes.

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Another way to measure bone-density is called peripheral bone mineral density testing. It is often used in the United States to show people if they are in danger of osteoporosis. A moveable machine does the test.

Medical testing companies sometimes perform this examination at an office or other place of business. The test costs less than the DXA. But peripheral testing measures only one part of the body. Usually that place is the wrist, the heel, or the bones between finger joints.

If the testing device is in good condition, it probably will give satisfactory results. But what if the patient has normal bones in the tested areas, but not in others? A person could appear normal on the test. But she still might have osteoporosis in her backbone or hips.

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Differences in bone mineral density among body parts are most often found in women who recently ended their childbearing years. The density may be normal at one place but low at another. Bone mineral density in the spine decreases first. A woman's bone mineral density becomes about the same in all parts of her body after she is seventy years old.

The lower-cost test may not give complete answers. But it can warn that osteoporosis threatens or has started.

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The National Osteoporosis Foundation has advised several steps toward the goal of healthy bones. Its experts say get enough calcium and vitamin D. The experts say do not smoke or drink too much alcohol. Talk to your healthcare provider about bone health and a possible bone mineral density test.

The NOF's guide for healthcare providers says people over fifty should get one thousand two hundred milligrams of calcium every day. The guide also says this age group should get eight hundred to one thousand International Units of Vitamin D. It says Vitamin D-Two and Vitamin D-Three are both good for bones.

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Milk and milk products contain calcium. So do fish with soft bones, like salmon, and dark green leafy vegetables. Some orange juice, bread and cereals may have calcium added.

Some people also take pills containing calcium. But be careful about how much calcium you take. You should not have more than two thousand five hundred milligrams a day. That total includes calcium from food and all other sources. Too much calcium can cause problems like kidney stones.

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Vitamin D absorbs, or takes up, calcium. Fish, cereal and milk are good sources of Vitamin D. If you spend at least fifteen minutes a day in the sun without a product to block the sun's radiation, you probably get enough Vitamin D.

Several kinds of drugs treat osteoporosis. America's Mayo Clinic medical centers say bisphosphonates are the most popular. Fosamax, Actonel and Boniva are products of this family of drugs. The Mayo Clinic advises that these drugs are very effective and appear safe for most people if taken as directed. Fosamax has been sold for at least ten years. Other drugs proven effective for osteoporosis are hormones and parathyroid hormone.

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Doctors say physical exercise can help keep bones strong.

Doctors who treat osteoporosis patients say physical exercise can help the bones. For active people, lifting weights or playing tennis, slow running and dancing can be helpful.

Some older adults worry about exercising. They believe they could hurt themselves. The Mayo Clinic says that could be true if they have not exercised in the past. It says people who have not been active in the past need a doctor's advice before starting.

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Some people who are afraid of exercise worry about its effects on their joints, especially the knees. They are afraid exercise might cause osteoarthritis, a condition in which connective tissue around the bones wears down. A study in The Netherlands found that could be true. Results of the study were reported recently in the publication "Arthritis Care and Research."

Researchers studied one thousand six hundred seventy eight people over a period of twelve years. The subjects were between fifty-five and eighty-five years old. The results linked knee osteoarthritis to high mechanical strain -- activities that are hard on joints.

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But another study found that regular exercise does not harm joints. Those findings were reported in "The Journal of Anatomy." Scientists from Germany and the United States considered earlier research on the effect of exercise on joints. They did not find a link between regular exercise and knee osteoarthritis.

If you are still worried about exercise for osteoporosis, why not go for a walk? But you have to do it correctly. The Mayo Clinic says hold your head high. Straighten your back and neck as much as possible. Tighten the chest muscles. As you move along, let your shoulders and arms move freely and naturally.

Walking places the full weight of your body on your bones. It also has other good effects. It raises the levels of chemicals in the brain known as endorphins. They reduce pain and make you feel happier.

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This SCIENCE IN THE NEWS program was written by Jerilyn Watson. Our producer was Brianna Blake. I'm Bob Doughty.

VOICE ONE:

And I'm Barbara Klein. Join us again next week for more news about science in Special English on the Voice of America.