手機輻射致癌嗎？科學家研究十年后有了新發(fā)現(xiàn)

手機致癌嗎?

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.

盡管已研究多年，這個問題依然沒有明確的答案。但是衛(wèi)生官員稱，周五公布的兩項分別在大鼠和小鼠身上進行的相關政府研究表明，即便有風險，也是比較小的。

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.

多年來，隨著手機成為大部分人生活不可或缺的一部分，有關它們的安全問題引發(fā)了廣泛的關注和激烈的討論。即便是微不足道的風險也可能影響成千上百萬人。

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.

這兩項針對手機輻射影響的研究歷時10年，耗資2500萬美元(約合1.6億元人民幣)，被認為是迄今為止最全面的。

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.

研究認為，雄性大鼠的心臟腫瘤和高劑量的手機輻射有關。但雌性大鼠和所有小鼠均未出現(xiàn)這個問題。

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.

美國國家毒理學計劃(National Toxicology Program)的高級科學家約翰·布赫(John Bucher)在一場電話新聞發(fā)布會上說，研究中使用的這些嚙齒動物連續(xù)兩年每天接受九小時的輻射，超過大量使用手機的人，因此相關結果不直接適用于人類。

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.

他說，研究結果并沒有促使他改變自己的手機使用習慣或勸說家人這么做。但他也指出，大鼠的心臟腫瘤，即所謂的惡性神經鞘瘤，與聽神經瘤類似。后者是人體內的一種良性腫瘤，涉及連接耳朵和大腦的神經，一些研究認為它與使用手機有關。

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

他說，在這個問題上已經開展了近20項動物研究，“就癌癥而言，絕大多數的結果都是陰性的。”

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，另外一些機構正在研究人們使用手機的情況，試圖確定它是否和任何類型的癌癥的患病有關。

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.”

美國食品藥品管理局(Food and Drug Administration，簡稱FDA)發(fā)表了一份聲明，稱它尊重毒理學計劃的研究，并對其他很多有關手機安全的研究進行了檢查，“沒有發(fā)現(xiàn)充分的證據表明，暴露在當前的射頻暴露極限或以下會對人的健康產生不良影響”。

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設備和輻射健康中心主任杰弗里·舒連(Jeffrey Shuren)的這份聲明還寫道，“即使絕大部分成年人每天頻繁使用手機，我們也沒有看到腦瘤等病例的增加。”

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.

聲明說，美國聯(lián)邦通信委員會(Federal Communications Commission)會對手機的射頻能量制定輻射極限，但它依賴FDA和其他衛(wèi)生機構提供科學的建議來確定這些極限。

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.

衛(wèi)生官員對擔心相關風險的人給出了常識性的建議：減少使用手機的時間;使用耳機或揚聲器模式，這樣手機就不會貼著頭部;以及避免在信號微弱時打電話。布赫指出，當用戶在信號不好或時有時無的地方時，手機不得不更加努力地連接，導致釋放的輻射增加。

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.

新研究在接受射頻輻射的小鼠和大鼠的大腦和另外一些器官中也發(fā)現(xiàn)了腫瘤。但布赫說這些發(fā)現(xiàn)“很模糊”，強調只有心臟腫瘤提供的證據足以讓研究人員采信。他說，其他可能的影響需進行進一步的研究。

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.

另一些人覺得，即使是模糊的發(fā)現(xiàn)也值得關注。加州大學伯克利分校公共衛(wèi)生學院家庭和社區(qū)健康中心(Center for Family and Community Health at the School of Public Health)主任喬爾·M·莫斯科維茨(Joel M. Moskowitz)說，根據這項研究的總體結果，政府應該重新評估和加強對手機可釋放多少以及什么類型的輻射的限制。

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.

科學家們不知道為什么只有雄性大鼠會患上心臟腫瘤，雌性大鼠卻沒有，但布赫說，一種可能性是雄性體型更大，吸收的輻射更多。

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.

這兩項研究還發(fā)現(xiàn)，暴露在輻射中的動物體內的一些DNA受損。這有些意外，因為科學家本以為射頻輻射不同于X射線中的電離輻射，不會損壞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.

“我們覺得對這些結果的了解還不夠，無法對結果有高度的信心。”

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.

一個看似矛盾并令研究人員感到困惑的發(fā)現(xiàn)是，暴露在手機輻射下的大鼠實際上比對照組活得更長。布赫說，一個可能的解釋是，輻射或許會緩解炎癥，并減輕一種慢性腎臟疾病的嚴重程度。這種疾病在老年大鼠中很常見，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.”

被問及使用手機是否有可能幫助人們活得更久，布赫說：“針對人類的推斷須采取大量超出我們目前研究范圍的舉措。我不認為這個問題目前能夠具體回答。”

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.

周五發(fā)布的報告被認為是草稿，意在征求公眾意見，并于3月26至28日在北卡羅來納州三角研究園(Research Triangle Park)的環(huán)境衛(wèi)生研究所接受外部專家的檢查。