Cancer to Become World's Leading Killer
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This is SCIENCE IN THE NEWS in VOA Special English. I'm Steve Ember. And I'm Barbara Klein. This week, we will tell about cancer. Health experts say it will soon become the world's leading killer. We also will present evidence of a suspected link between tobacco smoke and behavioral problems in boys with asthma. And, we will tell about an effort to count all of the world's sea life.
Health experts say cancer will become the leading cause of death in the world by the year two thousand ten. An agency of the World Health Organization released a report on cancer last month. Health experts predicted the number of people who die from cancer will soon be greater than deaths from AIDS, tuberculosis and malaria combined. The experts say more people will die from cancer than heart disease, the current leading killer.
The report says one reason for the growing deadliness of cancer is more people smoking cigarettes in developing countries. The report says forty percent of the world's smokers are believed to live in China and India alone.
Other things are believed to have an effect. They include high fat diets, fast food meals and reduced physical activity.
The WHO report says an estimated twelve million people will be found to have some form of cancer this year. It predicts that more than seven million people will die early from the disease. And, more than five million of the new cancer cases will involve people in developing countries.
The number of cancer cases and deaths from cancer are expected to increase one percent each year. Experts are predicting the largest increases will be in China, Russia, and India.
Without new treatments, the WHO said, the number of new cancer patients could increase to twenty-seven million a year by twenty-thirty. The number of them who die each year from the disease could reach seventeen million.
A few kinds of cancer are more common in some areas. For example, the rate of breast cancer in Japan, Singapore and Korea is now three times what it was forty years ago. Stomach cancer has become more common in some areas where food is often not stored in a cold place.
Another report says the number of men and women dying from cancer has dropped in the United States. It was the first reported drop in American cancer cases and deaths since the nation began collecting such information.
The Journal of the National Cancer Institute published the report last month. It said the drop was mainly the result of fewer cases of lung, prostate and colorectal cancer in men. In women, it resulted from fewer cases of breast cancer and colorectal cancer.
The American Cancer Society says governments can do things to help prevent the increase in cancer cases and deaths. One idea is to provide poor and developing nations with vaccines that help to prevent some cancer-causing infections. One example of a cancer causing infection is human papillomavirus. This virus can cause cervical cancer in women.
Another suggestion is more support for tobacco-control programs. And the Cancer Society also says health officials and governments should invest in cancer research and early detection.
An American study has shown a link between tobacco smoke and behavioral problems in boys with asthma. The problems include higher than normal levels of excitability, aggression and depression.
Researchers with the Cincinnati Children's Hospital Medical Center carried out the study. They examined two hundred twenty boys and girls. All of the children were between six and twelve years old. Sixty-one percent of them were boys. Fifty-six percent were African-American.
Seventy-seven percent of the children had moderate to severe asthma. The other boys and girls had milder forms of the breathing disorder. Each child had no other health problem.
To be considered for the study, children were supposed to be close to cigarette smoke at least five times a day. The researchers asked parents to estimate the number of cigarettes smoked near each child. The average was thirteen cigarettes a day.
The researchers tested blood from the children for evidence of cotinine, a tobacco byproduct. Cotinine levels in blood are often used to measure exposure to tobacco smoke. The researchers compared cotinine levels to behavioral problems that parents observed in the children during a two-week period.
The study found the girls were breathing in more tobacco smoke than the boys. But there was no increase in behavioral problems among the girls. For the boys, the results were different. The more contact the boys had with tobacco smoke the more likely they were to have recognizable behavior problems, such as extreme excitability and aggression. The boys also were more likely to have signs of emotional problems like anxiety and depression.
The researchers say more studies are needed to learn the reason for the different effects of tobacco smoke on boys and girls. They say their findings show that even low levels of smoke may cause behavior problems in children with asthma or others at risk.
Kimberly Yolton was the lead writer of the report. She says there is no information to explain in detail why tobacco smoke causes behavioral problems in children with asthma. But she says there is much evidence that nicotine in tobacco smoke affects the nervous system, and child development and behavior.
The report appeared last month in the Journal of Development and Behavioral Pediatrics.
For the first time, researchers are creating a complete count of the world's sea life. The project, called the Census of Marine Life, is to be carried out over ten years. The census is to be finished in two thousand ten. Researchers from more than eighty countries are involved in the project. It is being paid for jointly by governments, businesses and other groups.
Recently, the researchers announced some of their findings. Bob Gagosian works for the Consortium for Ocean Leadership in Washington, D.C. He helps to supervise the project.
BOB GAGOSIAN: "There are about two thousand scientists worldwide involved. Just about every country is involved in some way. Everywhere they have gone they have found new things. The ocean basically is unexplored from the point of view of marine organisms."
That was Bob Gagosian of the Consortium for Ocean Leadership. Researchers have placed small markers on hundreds of fish and marine animals. This lets them watch their movement by satellite and identify the areas where sea creatures gather.
Ron O'Dor is a scientist with the Census for Marine Life. He says current knowledge of life on the ocean floor is especially limited.
RON O'DOR: "Ninety percent of all the information we have is from the top hundred meters of the ocean."
That was Ron O'Dor of the Census for Marine Life. He says the sea floor is, on average, four thousand meters deep. So scientists are using robotic devices that can dive far below what people have seen in the past. They are now discovering strange, new species of plants, animals and organisms surviving near hot currents that come out of the ocean floor.
Among the project's findings is one that a group of Antarctic islands are richer in animal life than the world famous Galapagos Islands.
A report in the Journal of Biogeography describes how a team from the British Antarctic Survey and University of Hamburg searched the South Orkney Islands. The team spent seven weeks searching the South Orkney Islands in two thousand six. They searched as deep as one thousand five hundred meters underwater. The species they found were compared to information gathered over the past century. The team found the islands and nearby waters are home to more than one thousand two hundred known species.
Since the census began, more than five thousand three hundred new marine animals have been identified. Scientists have found a new species of blind lobster and giant bacteria, to name a few. In all, researchers say they hope to find examples of two hundred thirty thousand species during the census. Some say that is still only a small percentage of all the creatures living in the sea.
This SCIENCE IN THE NEWS program was written by Lawan Davis and Brianna Blake, who also was our producer. I'm Barbara Klein. And I'm Steve Ember. Join us again next week for more news about science in Special English on the Voice of America.