研究人员称无需担心手机会导致肿瘤

Researchers: No Worry About Cancer From Cellphones

From VOA Learning English, this is the Health & Lifestyle report.

Two United States government studies of cellphone radiation have found a weak link to an increased risk of cancer in animals.

But government officials and scientists are telling cellphone users not to worry. They say it is safe to use your mobile device.

Earlier studies of cellphone users had found little reason for concern.

The latest research took a close look at the effects of very high radiation levels in animals to answer some questions that could not be tested on human subjects.

In one study, researchers left cellphones in an area with rats. The researchers say radiation from the devices may have been responsible for a small increase in an unusual form of heart tumor¹ in male rats. Yet there were no big problems in female rats or in a separate study of mice.

The Associated Press (AP) says the scientists could not find strong evidence for concern about brain tumors.

Reaction to the findings

John Bucher is with the National Institute of Environmental Health Sciences. He was the lead writer of the report on the study. He told the AP he is not changing his cellphone use or asking his family to.

Otis Brawley is the American Cancer Society’s chief medical officer. After reading the studies, he said, “I am actually holding my cellphone up to my ear.”

The rat and mice studies are not the same as real-life cellphone use, he noted².

John Bucher said the findings of the rare nerve-tissue tumor found in the hearts of male rats does not mean humans should be worried.

His agency carried out a $25 million study for the Food and Drug Administration (FDA), which quickly said cellphones are safe.

Bucher said average cellphone use is “very, very, very much lower than what we studied.”

High radiation levels

He told reporters the rats and mice were exposed to the radiation for nine hours a day and for a period of up to two years. The radiation levels were so high that humans would only experience it for a short time.

He said, “At best, it might be a weak carcinogen ... if, in fact, it is a carcinogen."

For some unknown reason, the rats exposed to the radiation lived longer than the non-radiated rats. Bucher said that could be just chance, or it could be that the radiation reduced the risk of a rat disease.

The program released early test results two years ago. The earlier report showed a small risk of increased brain tumors in male rats. However, the final results were unable to confirm that.

Other changes noted

The new rat study found evidence for increases in damage to DNA³, brain tumors and a few other cancers, but it was not clear that it was related to the cellphones.

“Evidence of DNA damage was seen in some tissues of some animals,” Bucher said. He added that he didn’t have the evidence to comment on its biological importance.

Still, it was surprising that the animals did experience other effects, even if they were not at high enough levels to be important, said Leeka Kheifets. She is an epidemiology professor at the University of California, Los Angeles. She is also the former head of radiation studies for the World Health Organization.

“There is some concern that there is so much activity going on,” she said. But “it’s not like the sky is falling, a huge effect.”

The findings failed to satisfy those concerned about cellphone radiation, like David Carpenter. He is the head of environmental health at the State University of New York in Albany. He said the studies were not large enough to uncover some rare problems and that the findings about brain tumors “cannot be dismissed.”

“It’s not anywhere near as dangerous as cigarettes,” Carpenter said. But he added that there is a real danger from continual use of a cellphone.

In 2011, a working group of the International Agency for Research on Cancer said cellphones could possibly cause cancer. But many studies over the years have found little evidence of a problem.

I'm Jonathan Evans.

Words in This Story

mobile – adj. involving something that can be moved

tumor – n. a mass of tissue found in or on the body that is made up of abnormal cells

carcinogen – n. a substance that can cause cancer

epidemiology – n. the study of how disease spreads and can be controlled

expose – v. to cause to be affected or influenced by something; to leave without shelter or protection

1 tumor   

n.（肿）瘤，肿块(英)tumour

参考例句：

• He was died of a malignant tumor.他死于恶性肿瘤。
• The surgeons irradiated the tumor.外科医生用X射线照射那个肿瘤。

2 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

3 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。