This is Bob Doughty. And this is Sarah Long with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in science. Today, we tell about the disease arthritis.

Millions of people around the world suffer from arthritis. In the United States alone, more than twenty-million people have the disease. It affects the joints, the places where bones connect. Arthritis causes inflammation. It makes the area around the joints swell or grow larger. It makes the affected area red, painful and difficult to move. Arthritis affects several parts of the body. They include the neck, back, knees, hips and hands. Arthritis does not kill people, but there is no cure for the disease. Severe arthritis can prevent a person from leading a normal life. Some patients must have operations to replace their joints.

Americans spend thousands of millions of dollars each year trying to ease the pain of arthritis. Many patients take drugs ordered by their doctors. Other people take less traditional medicines and substances. Still others have acupuncture, an ancient Chinese method of reducing pain and improving health. Scientists say some methods of treating the disease are useless. These include wearing copper jewelry or using metal magnets. They also say being stung by insects does not help arthritis and may be dangerous. But some people say these methods help them. Many arthritis sufferers say they would do almost anything to stop the pain.

There are more than one-hundred forms of arthritis. The two major ones are osteoarthritis and rheumatoid arthritis. Osteoarthritis usually affects older people. It is caused by the destruction of cartilage. This is the connective tissue at the ends of bones. Cartilage permits the bones to slide smoothly across each other. In people with arthritis, the cartilage breaks down under the force of repeated movement. In severe cases, the bones move against each other. This causes severe pain.

Rheumatoid arthritis usually affects people between twenty and forty years of age. It starts when material in a joint attacks the bone and the cartilage. Doctors say this happens when the body attacks its own system against disease, called the immune system. Or, tiny organisms may be responsible. Rheumatoid arthritis can spread throughout the body. It can harm organs and connective tissue.

Doctors say simple measures can help many people with arthritis. For example, they advise losing weight if a person is too fat. This is because extra weight causes more pressure on joints such as the knees and hips. Doctors also strongly suggest some kinds of exercise for arthritis patients. Experts say swimming, water exercises and walking are among the best. These activities help keep the joints moving, strengthen muscles and may reduce pain.

Some arthritis patients take traditional medicines like aspirin and acetaminophen to ease pain. Other people report that glucosamine and chondroitin help their arthritis. These dietary supplements do not require an order by a doctor. Glucosamine is made from the shells of seafood like crabs, shrimp and lobster. Chondroitin comes from the breathing tubes of cows.

Scientists are not sure how these supplements ease the pain of arthritis. However, one study reportedly showed that glucosamine may help slow the breaking down of cartilage. The National Institutes of Health is the government's health policy and research agency. The N-I-H is preparing a long-term study of glucosamine and chondroitin. The agency is accepting patients from all over the country for this study.

A National Institutes of Health agency also is studying acupuncture to see it if helps patients with arthritis of the knee. Hundreds of people older than fifty are taking part in this study. During acupuncture, very small, sharp needles are placed in the skin at targeted body points. Millions of people in many countries have used acupuncture to ease pain. Researchers in the American study hope to learn more about how it works.

Some doctors advise their arthritis patients to take medicines called non-steroidal anti-inflammatory drugs. These drugs include aspirin, naproxen and ibuprofen. They block production of substances called prostaglandins in the body. Prostaglandins do many things in the body. They can cause inflammation. However, prostaglandins also protect the lining of the stomach and the intestines. Blocking this action could cause dangerous bleeding in those organs.

In Nineteen-Ninety-Nine, drug companies introduced two new medicines for arthritis. Patients and doctors welcomed these drugs, Vioxx and Celebrex. The two drugs block the prostaglandins that cause inflammation. But the drugs do not suppress the prostaglandins that protect the stomach. So these medicines do not increase the risk of dangerous bleeding.

Americans spend more than six-thousand-million dollars each year on arthritis medicines. Some reports say more than sixty-percent of this money is for Vioxx and Celebrex. One reason is that drug companies spend millions of dollars to tell the public about these drugs through advertising in the media. There are many television advertisements for the drugs.

The federal government ordered that one of these ads be changed. The Food and Drug Administration said the ad claimed too much effectiveness for Celebrex.

Recently reported studies of Vioxx and Celebrex have caused another kind of concern. The Journal of the American Medical Association published studies on the two drugs. The studies showed a small increase in problems including heart attacks and some kinds of strokes among people taking the drugs. However, the manufacturers of the two drugs say other studies do not show these problems.

One of the mysteries of osteoarthritis is why some people get it while others do not. For many years, doctors have known that people suffer from the disease as they grow older. However, many people live long lives without ever getting arthritis. Also, if age were the only cause, why would people get arthritis in one hip and not the other?

Doctors say some people are thought to have genes that may start arthritis. Some scientists believe this results from differences in the body's ability to produce collagen. This protein is the structural part of cartilage.

More women suffer from osteoarthritis than men do. This may result from decreasing hormone levels as a woman grows older. Osteoarthritis can begin long before a woman completely stops producing the hormone estrogen. In a recent study, the average age for a woman beginning to develop osteoarthritis was between forty and forty-five.

Another risk for arthritis appears to be former injuries to cartilage, which cannot repair itself. Old injuries to ligaments may also be a cause. Ligaments are bands of tissue that connect bones and hold them in place.

Experts say there is new hope today for arthritis patients. Scientists are working to develop new treatments for the disease. Some scientists are searching for a chemical substance in the body called a biomarker. The presence of this biomarker could show if the disease is progressing and if treatment is helping.

Recently, doctors have begun injecting a fluid into arthritis patients' knee joints to improve motion. Doctors also are harvesting cartilage from patients' knees and growing cells in the laboratory. Then they inject the cells into the patients' knee joints. The goal is to develop healthy new tissue.

Doctors also perform operations to remove severely diseased knee and hip joints. This surgery replaces the joints with metal or plastic joints. Doctors perform hundreds of thousands of knee and hip replacement operations each year in the United States.

For example, a teacher from Elk Grove, Illinois, says he suffered for years from an extremely painful hip caused by arthritis. Finally he decided to have a hip replacement operation. Now he takes long walks, rides a bicycle and plays golf. He says he wishes he had had the operation years ago.

This SCIENCE IN THE NEWS program was written by Jerilyn Watson. It was produced by Cynthia Kirk. This is Bob Doughty. And this is Sarah Long. Join us again next week for more news about science in Special English on the Voice of America.