手機(jī)輻射究竟能否致癌？老鼠實(shí)驗(yàn)僅供參考

Do cellphones cause cancer? Most health authorities do not think so, but a new federal study could reignite the controversy over this issue.

手機(jī)致癌嗎?大部分健康專家不這么認(rèn)為，但是美國聯(lián)邦政府的一項(xiàng)新研究可能重新引發(fā)關(guān)于這個問題的爭論。

The preliminary study, released Friday, found that radiation from cellphones appears to have increased the risks that male rats developed tumors in their brains and hearts. But there are many caveats and some experts are debunking the study.

周五公布的這項(xiàng)初步研究發(fā)現(xiàn)，手機(jī)輻射似乎增加了雄鼠患上腦部和心臟腫瘤的風(fēng)險(xiǎn)。但有很多需要解釋的地方，而且有些專家并不認(rèn)同這項(xiàng)研究。

Who conducted the study? Are they credible?

誰進(jìn)行了這項(xiàng)研究?他們可信嗎?

The study is from the National Toxicology Program, an interagency group in the Department of Health and Human Services whose job it is to assess the possible risks of chemicals.

這項(xiàng)研究是美國國家毒物管理局(National Toxicology Program)做的，它是美國衛(wèi)生與公眾服務(wù)部(Department of Health and Human Services)的一個跨部門機(jī)構(gòu)，其職責(zé)是評估化學(xué)物質(zhì)的潛在風(fēng)險(xiǎn)。

How was the study done? 研究是如何進(jìn)行的?

Rats lived in special chambers where they were exposed to different levels of radiation of the type emitted by cellphones for nine hours a day, every day. The exposure started before they were born and continued until they were about 2 years old.

大鼠住在特殊的房間里，每天接受九小時不同強(qiáng)度的輻射，輻射類型與手機(jī)輻射相同。從出生前一直持續(xù)到約2歲大。

What did they find? 他們發(fā)現(xiàn)了什么?

About 2 to 3 percent of the male rats exposed to the radiation developed malignant gliomas, a brain cancer, compared with none in a control group that was not exposed to radiation.

約2%至3%受到輻射的雄鼠患上了惡性膠質(zhì)瘤——它是一種腦部癌癥——而沒有受到輻射的對照組沒有此類病例。

About 5 to 7 percent of the male rats exposed to the highest level of radiation developed schwannomas in their hearts, compared with none in the control group. Schwannomas are tumors that occur in cells that line the nerves. The authors concluded the brain and heart tumors were “likely caused’’ by the radiation.

受到最高強(qiáng)度輻射的雄鼠有大約5%至7%患上了心臟神經(jīng)鞘瘤，而對照組中沒有此類病例。神經(jīng)鞘瘤是由周圍神經(jīng)的神經(jīng)鞘所形成的腫瘤。作者們認(rèn)為，腦部和心臟腫瘤“可能”是輻射“造成的”。

What about female rats?

那雌鼠呢?

Oddly enough, the incidence of tumors in females was minimal, barely different from the control group. It is not clear why the results would vary between the sexes, which is one reason some experts are questioning the findings.

奇怪的是，雌鼠的腫瘤發(fā)病率極低，與對照組幾乎沒有差別。不同性別出現(xiàn)不同結(jié)果的原因不明，這一點(diǎn)也令有些專家對研究結(jié)果產(chǎn)生質(zhì)疑。

What are other caveats?

還有什么需要我們知道的?

Even for males, the differences between particular groups of rats and the control group were not statistically significant. Another anomaly was that the rats exposed to the radiation lived longer on the whole than animals in the control group. And schwannomas can occur all over the body, not just the heart, but the study did not find increased rates in other organs.

即便就雄鼠而言，某些組與對照組之間的差別從統(tǒng)計(jì)學(xué)角度講也不是很明顯。還有一個反?，F(xiàn)象，受到輻射的大鼠的壽命，總體而言長于對照組。而且，神經(jīng)鞘瘤可能在全身各處發(fā)作，不只是心臟，但是這項(xiàng)研究沒有發(fā)現(xiàn)其他器官的神經(jīng)鞘瘤發(fā)生比例升高。

Also it was unusual that the control group had zero tumors. In previous studies at the National Toxicology Program, an average of 2 percent of rats in control groups developed gliomas. Had that happened in this study, there would have been virtually no difference between the exposed rats and the controls.

另一個反常情況是，對照組完全沒有腫瘤病例。在國家毒物管理局之前的研究中，對照組平均會出現(xiàn)2%的神經(jīng)膠質(zhì)瘤。如果同樣的情況出現(xiàn)在這項(xiàng)研究中，那受到輻射的大鼠與對照組之間實(shí)際上沒有差別。

“I am unable to accept the authors’ conclusions,” said one reviewer of the study, Dr. Michael S. Lauer, deputy director for extramural research at the National Institutes of Health. Dr. Lauer, whose comments were in an appendix to the report, said it was likely that the findings represented false positives.

“我無法接受作者們的結(jié)論，”這項(xiàng)研究的一位評議人邁克爾·S·勞爾博士(Michael S. Lauer)說。他是國家衛(wèi)生研究院(National Institutes of Health)的院外研究副主任。勞爾的評審意見出現(xiàn)在這份報(bào)告的附錄里。他說，這些發(fā)現(xiàn)可能是錯誤判斷。

The amounts of radiation that rats were exposed to might be higher than what cellphone users typically experience, though toxicology studies often use higher doses to make sure to detect any effect that might exist.

這些大鼠受到的輻射強(qiáng)度可能高于手機(jī)用戶通常受到的輻射，不過毒物學(xué)研究一般都是使用更高劑量，以確保檢測到任何可能存在的影響。

So we can just dismiss this study and go on using our phones?

所以，我們可以不理會這項(xiàng)研究，繼續(xù)使用手機(jī)嗎?

Not totally. As the authors of the report write: “Given the extremely large number of people who use wireless communication devices, even a very small increase in the incidence of disease resulting from exposure to the RFR generated by those devices would have broad implications for public health.” RFR refers to radio-frequency radiation.

并不完全是這樣。就像那份報(bào)告的作者們寫的：“使用無線通訊設(shè)備的人數(shù)量眾多，那些設(shè)備產(chǎn)生的射頻輻射就算只是輕微提高發(fā)病率，也會對公共健康造成廣泛影響。”

Dr. Otis Brawley, chief medical officer of the American Cancer Society, issued a statement on Friday that called this study “good science,” and called for further research because the animal research used very high signal strengths.

周五，美國癌癥學(xué)會(American Cancer Society)的首席醫(yī)療官奧蒂斯·布勞利博士(Otis Brawley)發(fā)表了一項(xiàng)聲明，稱這項(xiàng)研究是“優(yōu)秀科學(xué)成果”，倡議進(jìn)行進(jìn)一步研究，因?yàn)閯游镅芯克玫男盘枏?qiáng)度很高。

But he said, “The NTP report linking radiofrequency radiation (RFR) to two types of cancer marks a paradigm shift in our understanding of radiation and cancer risk.”

但是他說，“國家毒物管理局的報(bào)告將射頻輻射與兩種癌癥聯(lián)系起來，標(biāo)志著我們在理解輻射和癌癥風(fēng)險(xiǎn)方面出現(xiàn)思考模式的轉(zhuǎn)變。”

Dr. David O. Carpenter, director of the Institute for Health and Environment at the University at Albany, said he thought the study provided backing for the human epidemiological studies that suggested cellphone use was associated with an increased risk of gliomas and acoustic neuromas, a type of schwannoma. “I think this is real,’’ he said, suggesting people used wired earpieces to talk on cellphones.

大衛(wèi)·O·卡彭特博士(David O. Carpenter)是紐約州立大學(xué)奧爾巴尼分校(Albany)健康和環(huán)境學(xué)院(Institute for Health and Environment)的院長。他說，他認(rèn)為這項(xiàng)研究為人類流行病學(xué)的研究提供了支持，表明使用手機(jī)與神經(jīng)膠質(zhì)瘤及聽神經(jīng)瘤(神經(jīng)鞘瘤的一種)的風(fēng)險(xiǎn)增加有關(guān)。“我覺得這是真的，”他說。他建議人們在接打電話時使用有線耳機(jī)。

What have other studies found?

其他研究發(fā)現(xiàn)了什么?

Dr. Carpenter’s view is not the prevailing one. Many studies have been conducted, including some very large ones like the Million Women Study in Britain, and a Danish study of more than 350,000 cellphone users. There also were studies examining the effects of these radio waves in animals and cells growing in petri dishes. The results are reassuring. There is no convincing evidence of any link between cellphone use and cancer or any other disease.

卡彭特的觀點(diǎn)不是主流觀點(diǎn)。之前有過很多研究，包括一些很大規(guī)模的研究，比如英國的百萬女性研究(Million Women Study)，以及丹麥對逾35萬手機(jī)用戶進(jìn)行的研究。還有些研究是檢驗(yàn)這些無線電波對動物以及在皮氏培養(yǎng)皿中生長的細(xì)胞的影響。這些研究的結(jié)果令人寬慰。沒有令人信服的證據(jù)表明，使用手機(jī)與癌癥或其他疾病之間存在聯(lián)系。

Also, the incidence of brain cancer in the United States has remained steady since 1992, despite the stark increase in cellphone use.

另外，從1992年至今，美國的腦部癌癥發(fā)病率始終很穩(wěn)定，盡管這期間手機(jī)使用量急劇上升。

The International Agency for Research on Cancer, part of the World Health Organization, rates cellphone radiation a “possible’’ human carcinogen, based on limited evidence in both people and animals. It gives the same rating to coffee and pickled vegetables.

世界衛(wèi)生組織(World Health Organization)的國際癌癥研究機(jī)構(gòu)(International Agency for Research on Cancer)基于人和動物身上的有限證據(jù)，將手機(jī)輻射列為“可能”對人類有致癌作用的物質(zhì)，與咖啡和咸菜屬于同一級別。

But don’t we know that radiation causes cancer?

但是，難道我們不知道輻射致癌嗎?

Ionizing radiation, the powerful type from nuclear weapons, nuclear power plants and X-ray machines, is strong enough to knock electrons off atoms and damage DNA. That can cause cancer. But the radiation from cellphones, called radio-frequency radiation, is nonionizing and not known to damage DNA.

核武器、核電站和X光機(jī)產(chǎn)生的強(qiáng)烈的電離輻射足以把電子從原子中釋放出來，損害DNA。那會致癌。但手機(jī)輻射是射頻輻射，不是電離輻射，不會損害DNA。

So what happens now?

接下來會怎樣?

The findings released Friday are preliminary and part of a larger study, so more data will be coming out, probably next year. The existing report will also be reviewed further by more experts.

周五公布的發(fā)現(xiàn)是初步試驗(yàn)，是一項(xiàng)更大規(guī)模研究的一部分，所以會出現(xiàn)更多數(shù)據(jù)，很可能明年公布?，F(xiàn)有的報(bào)告也將由更多專家進(jìn)一步評審。