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 tumor 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.
    约翰·布彻(John Bucher)就职于国家环境健康科学研究所,他是该研究报告的主要作者。他对美联社表示,他不会改变手机的使用或是要求家人这么做。

    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."
    奥蒂斯·布劳利(Otis Brawley)是美国癌症协会的首席医疗官。他在读完该研究报告后表示:“实际上我刚把手机拿到耳边。”

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

    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 DNA, 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.
    尽管如此,令人惊讶的是,这些动物确实经历了其它效应,即使它们的重要程度不高,Leeka Kheifets如是表示。她是加州大学洛杉矶分校的一位流行病学教授,也是世界卫生组织辐射研究的前任负责人。

    "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."
    这项调查结果并未满足那些担心手机辐射的人,例如戴维·卡本特(David Carpenter)。他是奥尔巴尼市的纽约州立大学环境健康方面的负责人。他说,这些研究尚不足以揭示一些罕见问题,而且有关脑瘤的研究结果无法被抛之脑后。

    "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.