手机辐射致癌吗？科学家研究十年后有了新发现

Do cellphones cause cancer?

手机致癌吗？

Despite years of research, there is still no clear answer. But two government studies released Friday, one in rats and one in mice, suggest that if there is any risk, it is small, health officials said.

尽管已研究多年，这个问题依然没有明确的答案。但是卫生官员称，周五公布的两项分别在大鼠和小鼠身上进行的相关政府研究表明，即便有风险，也是比较小的。

Safety questions about cellphones have drawn intense interest and debate for years as the devices have become integral to most people’s lives. Even a minute risk could harm millions of people.

多年来，随着手机成为大部分人生活不可或缺的一部分，有关它们的安全问题引发了广泛的关注和激烈的讨论。即便是微不足道的风险也可能影响成千上百万人。

These two studies on the effects of the type of radiation the phones emit, conducted over 10 years and costing $25 million, are considered the most extensive to date.

这两项针对手机辐射影响的研究历时10年，耗资2500万美元（约合1.6亿元人民币），被认为是迄今为止最全面的。

In male rats, the studies linked tumors in the heart to high exposure to radiation from the phones. But that problem did not occur in female rats, or any mice.

研究认为，雄性大鼠的心脏肿瘤和高剂量的手机辐射有关。但雌性大鼠和所有小鼠均未出现这个问题。

The rodents in the studies were exposed to radiation nine hours a day for two years, more than people experience even with a lot of cellphone use, so the results cannot be applied directly to humans, said John Bucher, a senior scientist at the National Toxicology Program, during a telephone news briefing.

美国国家毒理学计划(National Toxicology Program)的高级科学家约翰.布赫(John Bucher)在一场电话新闻发布会上说，研究中使用的这些啮齿动物连续两年每天接受九小时的辐射，超过大量使用手机的人，因此相关结果不直接适用于人类。

The results, he said, had not led him to change his own cellphone use or to urge his own family to do so. But he also noted that the heart tumors in rats — called malignant schwannomas — are similar to acoustic neuromas, a benign tumor in people involving the nerve that connects the ear to the brain, which some studies have linked to cellphone use.

他说，研究结果并没有促使他改变自己的手机使用习惯或劝说家人这么做。但他也指出，大鼠的心脏肿瘤，即所谓的恶性神经鞘瘤，与听神经瘤类似。后者是人体内的一种良性肿瘤，涉及连接耳朵和大脑的神经，一些研究认为它与使用手机有关。

He said that nearly 20 animals studies on this subject have been done, “with the vast majority coming up negative with respect to cancer.”

他说，在这个问题上已经开展了近20项动物研究，“就癌症而言，绝大多数的结果都是阴性的。”

Other agencies are studying cellphone use in people and trying to determine whether it is linked to the incidence of any type of cancer, Bucher said.

布赫表示，另外一些机构正在研究人们使用手机的情况，试图确定它是否和任何类型的癌症的患病有关。

The Food and Drug Administration issued a statement saying it respected the research by the toxicology program, had reviewed many other studies on cellphone safety, and had “not found sufficient evidence that there are adverse health effects in humans caused by exposures at or under the current radio-frequency exposure limits.”

美国食品药品管理局（Food and Drug Administration，简称FDA）发表了一份声明，称它尊重毒理学计划的研究，并对其他很多有关手机安全的研究进行了检查，“没有发现充分的证据表明，暴露在当前的射频暴露极限或以下会对人的健康产生不良影响”。

The statement, from Dr. Jeffrey Shuren, director of the FDA’s center for devices and radiological health, also said, “Even with frequent daily use by the vast majority of adults, we have not seen an increase in events like brain tumors.”

出自FDA设备和辐射健康中心主任杰弗里.舒连(Jeffrey Shuren)的这份声明还写道，“即使绝大部分成年人每天频繁使用手机，我们也没有看到脑瘤等病例的增加。”

The Federal Communications Commission sets exposure limits for radio-frequency energy from cellphones, but relies on the FDA and other health agencies for scientific advice on determining the limits, the statement said.

声明说，美国联邦通信委员会(Federal Communications Commission)会对手机的射频能量制定辐射极限，但它依赖FDA和其他卫生机构提供科学的建议来确定这些极限。

For people who worry about the risk, health officials offer common-sense advice: Spend less time on cellphones, use a headset or speaker mode so that the phone is not pressed up against the head and avoid trying to make calls if the signal is weak. Bucher noted that the radiation emitted increases when users are in spots where the signal is poor or sporadic and the phone has to work harder to connect.

卫生官员对担心相关风险的人给出了常识性的建议：减少使用手机的时间；使用耳机或扬声器模式，这样手机就不会贴着头部；以及避免在信号微弱时打电话。布赫指出，当用户在信号不好或时有时无的地方时，手机不得不更加努力地连接，导致释放的辐射增加。

The new studies also found tumors in the brains and some other organs in the animals exposed to the radio-frequency radiation. But Bucher said those findings were “equivocal,” emphasizing that only the heart tumors provided evidence strong enough for the researchers to trust. Other possible effects need more research, he said.

新研究在接受射频辐射的小鼠和大鼠的大脑和另外一些器官中也发现了肿瘤。但布赫说这些发现“很模糊”，强调只有心脏肿瘤提供的证据足以让研究人员采信。他说，其他可能的影响需进行进一步的研究。

Others felt that even the ambiguous findings were of concern. Joel M. Moskowitz, director of the Center for Family and Community Health at the School of Public Health, at the University of California, Berkeley, said that based on the overall results of the study, the government should reassess and strengthen the limits it imposes on how much and what types of radiation cellphones can emit.

另一些人觉得，即使是模糊的发现也值得关注。加州大学伯克利分校公共卫生学院家庭和社区健康中心(Center for Family and Community Health at the School of Public Health)主任乔尔.M.莫斯科维茨(Joel M. Moskowitz)说，根据这项研究的总体结果，政府应该重新评估和加强对手机可释放多少以及什么类型的辐射的限制。

Scientists do not know why only male rats and not females develop the heart tumors, but Bucher said one possibility is simply that the males are bigger and absorb more of the radiation.

科学家们不知道为什么只有雄性大鼠会患上心脏肿瘤，雌性大鼠却没有，但布赫说，一种可能性是雄性体型更大，吸收的辐射更多。

The studies also found some DNA damage in the exposed animals, a bit of a surprise because scientists had believed that radio-frequency radiation — unlike the ionizing radiation in X-rays — could not harm DNA.

这两项研究还发现，暴露在辐射中的动物体内的一些DNA受损。这有些意外，因为科学家本以为射频辐射不同于X射线中的电离辐射，不会损坏DNA。

“We don’t feel like we understand enough about the results to be able to place a huge degree of confidence in the findings,” Bucher said.

“我们觉得对这些结果的了解还不够，无法对结果有高度的信心。”

A seemingly paradoxical finding that has also puzzled the researchers is that the rats exposed to the cellphone radiation actually lived longer than the controls. One possible explanation, Bucher said, is that the radiation may ease inflammation, and lessen the severity of a chronic kidney disorder that is common in aging rats and can kill them.

一个看似矛盾并令研究人员感到困惑的发现是，暴露在手机辐射下的大鼠实际上比对照组活得更长。布赫说，一个可能的解释是，辐射或许会缓解炎症，并减轻一种慢性肾脏疾病的严重程度。这种疾病在老年大鼠中很常见，可能致死。

Asked if there was any chance that cellphone use could help people live longer, Bucher said: “The extrapolation to humans requires a number of steps that go beyond the realm of what we’re studying here. I don’t think that question is particularly answerable at the moment.”

被问及使用手机是否有可能帮助人们活得更久，布赫说：“针对人类的推断须采取大量超出我们目前研究范围的举措。我不认为这个问题目前能够具体回答。”

The reports issued Friday were considered draft versions released for public comment and a review by outside experts on March 26-28 at the environmental health institute in Research Triangle Park, North Carolina.

周五发布的报告被认为是草稿，意在征求公众意见，并于3月26至28日在北卡罗来纳州三角研究园(Research Triangle Park)的环境卫生研究所接受外部专家的检查。