Scientist debates conclusions on effects of cell phones
November 5, 1999
By Sylvia Westphal
Web posted at: 4:36 p.m. EST (2136 GMT)
(WebMD) -- A researcher, whose new study finds microwaves can harm rats' memory, says that extrapolating his findings to cell phones is premature.
A Wired News article November 3 said scientists had linked memory problems in rats "with the microwaves emitted by mobile phones."
But it would be premature to conclude that cell phones are dangerous, said University of Washington research professor Henry Lai, Ph.D., principal author of the research, to be published in the January issue of the journal Bioelectromagnetics.
"Somehow things got distorted," said Lai, referring to the interpretation of his results in the Wired News article. "It needs to be toned down a little bit."
Wired.com editor in chief George Shirk issued a statement saying, "Wired News stands by the story." Technology editor John Gartner said, "We haven't been alerted directly that (the researcher) found anything objectionable, as far as I know."
Wired reporter Kristen Philipkoski responded, saying, "I did make it clear that the story was about the effects of cell phones" in her interview with Lai. She said her story also included explanation that microwaves used in the rat study were "similar" and not identical to those emitted by cell phones.
Lai explained that the microwave frequency used in the study was 2,450 MHz, which is not the same as that emitted by cell phones -- 850 or 1,700 MHz. Also, the time and condition of the rats' exposure to the microwaves can't be compared to the exposure humans get while talking on a cell phone, he said.
"We still have a long way to go before we can extrapolate from rats to humans," Lai said.
Testing the memory
In the study, researchers placed rats in a chamber. Some were exposed to microwaves for one hour, while others were not, Lai said. A third group of rats were not placed in the chamber at all but were left in their cages as a control group.
The 100 rats were then put in a water maze, where they had to find their way to a platform. The water was mixed with milk so rats could not see the platform under water and instead had to find their way by learning and remembering its location. The researchers measured how long it took a rat to learn where the platform was.
When they compared the rats exposed to microwaves with those that hadn't been exposed, the scientists found a difference: Exposed rats took significantly longer to reach the platform.
According to Lai, these rats may have had an impaired spatial memory. This is the type of memory people use when walking through a city and "seeing" a map of the area in their heads.
But the reason the exposed rats performed differently is still unknown, he said. A possible clue lies in the brain chemical acetylcholine; a previous study by Lai indicates that this chemical decreases in the brains of rats exposed to microwave radiation.
Microwaves can melt the brain, too
Or the microwaves may have been responsible for heating the rats' brains, said William Ross Adey, Ph.D., a University of California, Riverside researcher who has studied the subject for more than 20 years.
Just as a microwave oven heats meat, microwaves can also heat living tissue, Adey said, and this may have impaired the rats' brain functions. Brain heating in rats has been observed under less powerful conditions than those in the new study, and this may explain why the exposed rats did not perform well.
No conclusion yet
Reaching a consensus in this field has been a challenge.
Agencies like the Food and Drug Administration and the Federal Communications Commission agree that the evidence against cell phone radiation is ambiguous. Studies exposing rats to microwaves at the frequency emitted by cell phones (about 835 MHz) remain inconclusive, as do studies of humans who use cell phones, according to an October 20 statement by the FDA.
"The available science does not allow us to conclude that mobile phones are absolutely safe, or that they are unsafe," according to the FDA statement.
The industry responds
A spokesman with a major communications and electronics company said he agrees with the FDA's position.
"The position of the industry is the same position of the scientific community," said Norm Sandler, spokesman for Motorola Inc., which manufactures cell phones. "That position has not changed over the number of years over which a considerable amount of research has been done all over the world."
Jacek Wojcik, M.D., of Ontario-based APREL laboratories, an independent consultant to the wireless industry, said more research needs to be done. "Until now they really couldn't find anything, but we can't disprove it is unsafe," Wojcik said.
For the estimated 80 million Americans who use cell phones, this might not bring immediate peace of mind. The FDA recommends those worried about possible health effects minimize their exposure to microwave emissions -- meaning spend less time on cell phones.
Copyright 1999 webmed, Inc. All rights reserved.
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