世界衛生組織(WHO)旗下的國際癌症研究署(IARC)五月卅一日發表報告,首度將手機列入人類致癌因子分類表,屬於2B級「可能為致癌因子」,與咖啡、汽油引擎廢氣、電焊煙霧以及極低頻電磁場同級。

由十四國卅一名科學家組成的工作小組從五月廿四日起,在法國里昂召開八天會議,評估暴露在電磁場(包括使用手機)環境中人和動物等所受健康影響的所有科學證據,並認為基於現有的有限數據,長期常用手機可能增加罹患「神經膠質瘤」(glioma)的風險。

神經膠質瘤是腦瘤一種,屬惡性腫瘤。工作小組報告中提到二○○四年後的一項研究顯示,連續十年平均每天講手機卅分鐘,罹患神經膠質瘤幾率將增加四○%。

IARC將致癌因子分為五個級別:1級確定為致癌因子、2A級極有可能為致癌因子、2B級可能為致癌因子、3級無法歸類為致癌因子,以及4級極有可能為非致癌因子。

工作小組主席南加大薩梅特博士表示,現有證據足以支持可能致癌結論,需要密切關注。

_________________________________________________________________

世界衛生組織首度承認,手機可能致癌。由於兒童頭蓋骨發育尚未完整,對於國人幾乎人手一機的現象,國內醫界建議,政府應該比照英國、德國,限制十四歲以下兒童禁止使用手機,以免危害健康。

手機可能致癌的爭議已討論多年,昨天終於獲世衛證實。世界各國一直有學術研究,指經常使用手機有致癌之虞,較明確的數據是全世界手機使用普及率最高的以色列,發現手機慣用手那一側,發生腮腺癌的比率較高,與使用手機高度相關。

北醫放射線科梁庭繼醫師表示,手機發射出的電磁波,和微波爐類似,原則上不會直接破壞細胞染色體,但手機使用時會放射頻率能量,間接影響染色體和細胞的新陳代謝,進一步造成病變;目前懷疑與腦神經膠質瘤較有相關,過去英國曾研究發現,使用手機超過十年,罹患腦瘤的機率增加。

小孩使用手機比成人更危險,研究發現,手機發出的電磁波可穿入成人頭蓋骨一公分內,但卻會「穿透」在發育中兒童的頭部,影響更大,家長太早讓孩子天天使用手機,其實是害了他們,政府應比照國外發布禁令,以免禍害下一代。

如何避免手機的危害?醫師建議,民眾可改用低能量或功能較簡單的手機,因為,越是功能複雜的手機如Iphone及三G手機,發射的電磁波越強,民眾接收時可改用免持聽筒,避免長時間講手機,以減少對身體的影響。

____________________________________________________

(CNN) -- Radiation from cell phones can possibly cause cancer, according to the World Health Organization. The agency now lists mobile phone use in the same "carcinogenic hazard" category as lead, engine exhaust and chloroform.

Before its announcement Tuesday, WHO had assured consumers that no adverse health effects had been established.

A team of 31 scientists from 14 countries, including the United States, made the decision after reviewing peer-reviewed studies on cell phone safety. The team found enough evidence to categorize personal exposure as "possibly carcinogenic to humans."

What that means is they found some evidence of increase in glioma and acoustic neuroma brain cancer for mobile phone users, but have not been able to draw conclusions for other types of cancers

"The biggest problem we have is that we know most environmental factors take several decades of exposure before we really see the consequences," said Dr. Keith Black, chairman of neurology at Cedars-Sinai Medical Center in Los Angeles.

The type of radiation coming out of a cell phone is called non-ionizing. It is not like an X-ray, but more like a very low-powered microwave oven.

"What microwave radiation does in most simplistic terms is similar to what happens to food in microwaves, essentially cooking the brain," Black said. "So in addition to leading to a development of cancer and tumors, there could be a whole host of other effects like cognitive memory function, since the memory temporal lobes are where we hold our cell phones."

Wireless industry responded to Tuesday's announcement saying it "does not mean cell phones cause cancer." CTIA-The Wireless Association added that WHO researchers "did not conduct any new research, but rather reviewed published studies."

The European Environmental Agency has pushed for more studies, saying cell phones could be as big a public health risk as smoking, asbestos and leaded gasoline. The head of a prominent cancer-research institute at the University of Pittsburgh sent a memo to all employees urging them to limit cell phone use because of a possible risk of cancer.

"When you look at cancer development -- particularly brain cancer -- it takes a long time to develop. I think it is a good idea to give the public some sort of warning that long-term exposure to radiation from your cell phone could possibly cause cancer," said Dr. Henry Lai, research professor in bioengineering at University of Washington who has studied radiation for more than 30 years.

Results from the largest international study on cell phones and cancer was released in 2010. It showed participants in the study who used a cell phone for 10 years or more had doubled the rate of brain glioma, a type of tumor. To date, there have been no long-term studies on the effects of cell phone usage among children.

"Children's skulls and scalps are thinner. So the radiation can penetrate deeper into the brain of children and young adults. Their cells are at a dividing faster rate, so the impact of radiation can be much larger." said Black of Cedars-Sinai Medical Center.

In February, a study by researchers at the National Institutes of Health, revealed radiation emitted after just 50 minutes on a mobile phone increases the activity in brain cells. The effects of brain activity being artificially stimulated are still unknown.

Neurosurgeon and CNN chief medical correspondent Dr. Sanjay Gupta says Tuesday's announcement, "dealt a blow to those who have long said, 'There is no possible mechanism for cell phones to cause cancer.' By classifying cell phones as a possible carcinogen, they also seem to be tacitly admitting a mechanism could exist."

Manufacturers of many popular cell phones already warn consumers to keep their device away from their body and medical experts say there other ways to minimize cell phone radiation.

The Apple iPhone 4 safety manual says users' radiation exposure should not exceed FCC guidelines: "When using iPhone near your body for voice calls or for wireless data transmission over a cellular network, keep iPhone at least 15 millimeters (5/8 inch) away from the body."

BlackBerry Bold advises users to "keep the BlackBerry device at least 0.98 inch (25 millimeters) from your body when the BlackBerry device is transmitting."

The logic behind such recommendations is that the further the phone is from the body, the less radiation is absorbed. Users can also use the speakerphone function or a wired earpiece to gain some distance.

Users can text instead of talk if they want to keep the phone away from their faces.

Finally, cell phones emit the most radiation when they are attempting to connect to cellular towers. A moving phone, or a phone in an area with a weak signal, has to work harder, giving of more radiation. So users can avoid using their cell phones in elevators, buildings and rural areas if they want to reduce their exposure, experts say.

http://edition.cnn.com/2011/HEALTH/05/31/who.cell.phones/index.html?hpt=hp_t1

airtsuei 發表在 痞客邦 PIXNET 留言(0) 人氣()