放心：至少现在认为手机与脑癌无关

　　美联社消息 美国研究人员称，他们还没发现手机和脑癌之间有任何关系。虽然现在下结论尚为时过早，不过至少现在你还可以继续放心使用手机。

　　发表在最近出版的《美国医学会杂志》上的一篇文章指出，曼哈顿的两个机构，美国健康基金会和斯洛恩·凯特林癌症纪念中心对891名年龄介于18岁到80岁之间的手机用户进行了问卷调查，内容包括他们使用的是何种牌子的手机，用了多长时间，以及每个月用手机通话时间和长短。在这些被调查者中，469位已诊断患有原发性脑癌，422位则未患该病。结果显示，参与调研的癌症患者每月平均电话使用时间为2.5小时，而未患病者为2.2小时。脑癌病人使用电话的平均持续时间为2.8年，未患病者为2.7年。没有发现使用手机和脑癌之间的有联系，也没有发现手机的使用量和脑癌之间的关系。

　　美国微波新闻节目主持斯雷辛说，这项调研是在1994年至1998年间进行，那时手机还没有现在普及。五年前移动电话用户使用的是模拟信号，而今天大多数用的是数码电话。数码信号的放射水平较低，但可能更具生物学活性，这意味着其发出的放射线与机体组织的作用与模拟信号的放射线不同。斯雷辛认为，对于长期使用手机是否有害，或者手机对儿童和青少年的作用是否与对成人不一样，现在作结论都为时过早。尽管从流行病学上研究手机和某些疾病的联系是有意义的，但研究的焦点应当弄清楚机体及脑组织与手机射线相互作用的基础是什么。微波新闻每月都有两次关于放射性问题的时事通讯。

　　《新英格兰医学杂志》也发布了类似的研究结果。由国家癌症研究所研究人员领导的一项涉及782个脑癌病人和 799个非癌症患者的研究发现，最长的手机使用者为每天至少使用一个小时，连续使用至少5年。即便如此，也没有发现的脑癌与手机的关系。因此该研究的作者认为需要更长时间的做进一步调查。

　　美国食品及药品管理局(FDA)和无线电工业正在继续合作研究手机的安全性问题。移动电信和互联网协会都发表声明表示它们欢迎《美国医学会杂志》的调查结果。

　　Study： Cell Phones， Brain Cancer， No Link

　　Researchers say they have not found any link between cell phone usage and brain cancer， but it might be too soon to know for sure.

　　You can keep calling people on your cell phone. For now， at least.

　　A study of nearly 900 cell phone users， conducted by the American Health Foundation and Memorial Sloan Kettering Cancer Center， both in Manhattan， found no connection between using the phones and brain cancer. "The data showed no correlation between the use of cell phones and the development of brain cancer. In addition， there was no association between the amount of cell phone usage and brain cancer，" writes lead author Joshua Muscat， of the American Health Foundation.

　　Patients 18 to 80 years old filled out a questionnaire that asked which brand of cell phone they used， how long they had been using the phone and how many minutes and hours per month they spoke on their cells. Of the 891 study participants， 469 were men and women diagnosed with primary brain cancer， while 422 did not have the disease.

　　The differences in cell phone use between those with cancer and those without were tiny. For example， the median monthly use of a cell for participants with cancer was 2.5 hours， as compared to 2.2 hours for those without， the study reported. The mean duration of use was 2.8 years for brain cancer patients and 2.7 years for healthy participants. The study will be published in the Dec. 20 issue of the Journal of the American Medical Association。”I think this rules out a role for cellular phones as a cause of increasing brain cancer rates in the U.S.，" says Tim Byers， an epidemiologist at the University of Colorado Health Sciences Center in Denver， who was not connected with the research.

　　Hold That Call"Clearly it's But don't sign up for the 600-free-minutes-a-month plan quite yet. a piece of good news，" says Louis Slesin of Microwave News， a bi-monthly newsletter covering radiation issues. "But it's only a very early snapshot of what's going on。”

　　Study participants were questioned between 1994 and 1998， when cell phone use was significantly lower than it is today， says Slesin. He also points out that the cell phones people were using five years ago used analog signals while today most people are on digital phones. Digital signals have lower radiation levels， but may be more biologically active， meaning the radiation emitted from them interacts with living tissue differently than radiation from analog signals.

　　Additionally， Slesin says， it is still too early to tell whether or not cell phone use has harmful effects over much longer periods， or whether the phones impact children and teenagers differently from adults. Although he thinks epidimiological studies linking cell phones to certain diseases are useful， he believes the focus of research at this point should really be on understanding the basics of how our bodies and brains interact with cell phone radiation. "We really don't understand much about this，" says Slesin.

　　Continued Research

　　The New England Journal of Medicine also released a study Tuesday， weeks ahead of schedule， showing similar results. Led by National Cancer Institute researchers， the study looked at 782 brain cancer patients and 799 people without cancer. Maximum cell phone use was at least an hour per day for five or more years， and no brain-cancer link was found even at that level. The authors of the second study said longer-term use needs more investigation.

　　The Food and Drug Administration and the wireless industry are collaborating on continued research into cell phone safety questions. The Cellular Telecommunications and Internet Association said in a statement that it welcomes the JAMA findings.

2001.07.26