Science News Digest
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 how diet and exercise can reduce a person's chance of developing diabetes. We tell about a World Health Organization campaign against leprosy. And we tell about a project to copy some trees at George Washington's home.
An American study has found that diet changes and exercise can delay the development of diabetes in people who are at risk for the disease. The study found that eating less fat and doing simple exercises could lower the risk of diabetes by fifty-eight percent. It also showed that a diabetes drug widely used by Americans also reduced the risk, but not as much.
Diet and exercise were so effective that the researchers ended the study one year early because it had answered the main research questions.
Smaller studies in China and Finland have shown that diet and exercise can delay diabetes in people at risk. However, the American study is said to be the first to show these effects among people in several racial or ethnic groups.
A person has diabetes when high levels of the sugar called glucose are found in the blood. Glucose levels increase when the body lacks or cannot use the hormone insulin. The pancreas is the organ of the body that produces insulin. The insulin helps glucose enter cells all over the body so that it can be used as fuel. Without insulin, glucose levels increase. This results in the disease diabetes.
In the United States, diabetes affects more than sixteen-million people. It is the leading cause of kidney failure and new cases of blindness among adults. It also is a major cause of heart disease and stroke.
About fifteen-million Americans have type two diabetes or adult onset diabetes. Type two diabetes usually develops in people thirty years of age or older. It is strongly linked to being overweight and not getting enough physical activity. Also, some racial or ethnic groups are more at risk. For example, black Americans have a sixty percent higher rate of type two diabetes compared to white Americans. Hispanic Americans have a ninety percent higher rate of the disease.
The National Institute of Diabetes and Digestive and Kidney Diseases organized the new study. It involved more than three-thousand-two-hundred people. All the people in the study were overweight. And they all had impaired glucose tolerance. This is a condition in which blood glucose levels are higher than normal but not yet diabetic.
Forty-five percent of the people in the study are members of minority groups that have a high rate of type-two diabetes. These groups include African Americans, Hispanic Americans, Asian Americans and American Indians. The study also involved other groups known to be at higher risk for type two diabetes. They include adults over sixty years of age and people who have a close family member with the disease.
People in the study were divided into four groups. Members of the first group were asked to reduce their body weight by seven percent. They were told to eat a low-fat diet and exercise about twenty minutes a day. Members of the second group were treated with metformin, a diabetes drug widely used in the United States. The third group took a harmless substance or placebo in place of the drug. Members of the second and third groups also received information about diet and exercise.
The fourth group was given the same information and the drug troglitazone. However, this part of the study was ended after studies found that troglitazone may cause liver damage.
After about three years, about twenty-nine percent of those who took the placebo developed type two diabetes. Twenty-two percent of the people who took metformin developed the disease. Only fourteen percent of those in the diet and exercise group developed the disease.
American Health and Human Services Secretary Tommy Thompson announced the findings of the study last month. He said that diet and exercise could help at least ten-million Americans sharply lower their risk for diabetes. He added that many other health problems could be avoided through diet and exercise.
You are listening to the Special English program SCIENCE IN THE NEWS on VOA. This is Sarah Long with Bob Doughty in Washington.
The World Health Organization says its ten-year campaign to remove leprosy as a world health problem has been successful. Gro Harlem Brundtland is head of the Geneva-based W-H-O. She says the number of leprosy cases around the world has been cut by ninety percent during the past ten years. She says efforts are continuing to completely end the disease.
Leprosy is caused by bacteria spread through liquid from the nose and mouth. The disease mainly affects the skin and nerves. However, if leprosy is not treated it can cause permanent damage to the skin, nerves, eyes, arms or legs.
In Nineteen-Ninety-Nine, an international campaign began to end leprosy. The World Health Organization, governments of countries most affected by the disease, and several other groups are part of the campaign. This alliance guarantees that all leprosy patients, even if they are poor, have a right to the most modern treatment.
Doctor Brundtland says leprosy is no longer a disease that requires life-long treatments by medical experts. Instead, patients can take what is called a "multi-drug therapy." This modern treatment will cure leprosy in six to twelve months, depending on the form of the disease. The treatment combines several drugs taken daily or once a month.
The W-H-O has given multi-drug therapy to patients free for the last five years. The members of the alliance against leprosy plan to target the countries still threatened by leprosy. Among the estimated six-hundred-thousand victims around the world, the W-H-O believes about seventy percent are in India. The disease also remains a problem in Africa and South America.
Tree experts have begun an effort to rebuild forests near the home of America's first president, George Washington. Last month, workers gathered buds from tall, old trees on the grounds of George Washington's home, Mount Vernon. It is in the state of Virginia, near Washington, D-C. The experts hope to produce genetic copies, or clones, of the trees and plant them on the property.
The process used to clone trees is called grafting. It has been done for thousands of years. A method called the T-bud technique often is used to copy trees. Workers begin by cutting the bark, or covering, on the side of a young tree. The cut is made in the shape of a cross, or the letter T. Next, the workers find a bud, or small growth, on the tree to be copied.
A small piece of wood under the bud is carefully removed from the tree. The bud is then put into the hole on the other tree. The bud is tightly tied in place and begins to grow.
Tree experts David Milarch (MILL-ark) and his son, Jared, are leading the efforts. They started the Champion Tree Project to produce genetic copies of the largest trees in the United States. Over the next ten years, the project plans to provide Mount Vernon with one-thousand trees for planting in nearby wooded areas.
As a special project, David and Jared Milarch offered to make clones of the thirteen oldest trees at Mount Vernon. They are huge, beautiful trees. George Washington supervised the planting of these trees more than two-hundred years ago.
The Milarch family plans to grow fifty copies of each tree in tree nurseries in Alabama and Oregon. They will return the trees to be planted at Mount Vernon in two years.
This SCIENCE IN THE NEWS program was written by Nancy Steinbach, Jill Moss and George Grow. 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.