Slashdot Mirror


Study of Cellphone Risks Finds 'Some Evidence' of Link To Cancer, At Least In Male Rats (nytimes.com)

An anonymous reader quotes a report from The New York Times: For decades, health experts have struggled to determine whether or not cellphones can cause cancer. On Thursday, a federal agency released the final results of what experts call the world's largest and most costly experiment to look into the question. The study originated in the Clinton administration, cost $30 million and involved some 3,000 rodents. The experiment, by the National Toxicology Program, found positive but relatively modest evidence that radio waves from some types of cellphones could raise the risk that male rats develop brain cancer. But he cautioned that the exposure levels and durations were far greater than what people typically encounter, and thus cannot "be compared directly to the exposure that humans experience." Moreover, the rat study examined the effects of a radio frequency associated with an early generation of cellphone technology, one that fell out of routine use years ago. Any concerns arising from the study thus would seem to apply mainly to early adopters who used those bygone devices, not to users of current models.

The lowest level of radiation in the federal study was equal to the maximum exposure that federal regulations allow for cellphone users. That level of exposure rarely occurs in typical cellphone use, the toxicology agency said. The highest level was four times higher than the permitted maximum. The rodents in the studies were exposed to radiation nine hours a day for two years -- far longer even than heavy users of cellphones. For the rats, the exposures started before birth and continued until they were about 2 years old. Some 2 to 3 percent of the male rats exposed to the radiation developed malignant gliomas, a deadly brain cancer, compared to none in a control group that received no radiation. Many epidemiologists see no overall rise in the incidence of gliomas in the human population.
"The study also found that about 5 to 7 percent of the male rats exposed to the highest level of radiation developed certain heart tumors, called schwannomas, compared to none in the control group," the NYT reports.

It's worth nothing that the rats were exposed to radiation at a frequency of 900 megahertz, the frequency used in the second generation of cellphones that prevailed in the 90s, when the study was first conceived. For comparison, fourth generation (4G) and fifth generation (5G) phones employ much higher frequencies, which are "far less successful at penetrating the bodies of humans and rats," the NYT reports.

3 of 153 comments (clear)

  1. Control Group by cirby · · Score: 5, Informative

    There's a note by one of the reviewers who points out that the control rats in the group that were compared to the "high radiation" male rats had a lower than expected number of gliomas, which is part of how they had "more gliomas" in that group.

    The number of male rats who had gliomas actually had a fairly typical number of gliomas for rats.

    There was also a bit of fudging up above: while 3000 or so rats were studied, they broke them into smaller numbers with different dose rates. There were only 94 rats in the group of "high exposure" rats.

    Basically, instead of a "3000 rat" study, it was a whole bunch of smaller studies. Treated as a 3000-rat whole, there was no effect, statistically.

  2. Wrong on all counts.... by Ozoner · · Score: 3, Informative

    Microwaves DON'T heat from the inside out:

    see Wickipedia: https://en.wikipedia.org/wiki/...

    "This idea arises from heating behavior seen if an absorbent layer of water lies beneath a less absorbent drier layer at the surface of a food; in this case, .... etc"

    The Microwave is NOT "tuned to be really well absorbed by oils and water for the purpose of cooking".

    again...

    " It is a common misconception that microwave ovens heat food by operating at a special resonance of water molecules in the food. As noted microwave ovens can operate at many frequencies"

    and

    "....the microwave oven's operating frequency has absolutely nothing to do with water or any other material resonant frequency whatsoever. Any coincidence is coincidental. The ISM (industrial-scientific-medical) band frequencies given out by the FCC were determined by regulatory/bureaucratic/interference considerations not by physics".

    1. Re:Wrong on all counts.... by Anonymous Coward · · Score: 2, Informative

      This is a prefect example as to why even WikiPedia says to not use it's site for research because it is edited by anyone with a internet connection without oversight.
      https://en.wikipedia.org/wiki/Wikipedia:Academic_use

      The commonly used frequency of microwaves, 2.45 gigahertz, is easily absorbed by water, fat, and sugar. "The waves are at the right frequency to penetrate deep into food and they deliver cooking power primarily to the food's water content. Water-free solids barely absorb microwaves." That's why microwave-safe containers don't get as hot as the food inside them. Microwaves heat food, like a cup of coffee or a slice of lasagna, by twisting water molecules back and forth. Water molecules are positively charged at one end and negatively charged at the other. A single water molecule looks like Mickey Mouse's head. You can think of the negatively charged oxygen atom as Mickey's face and the two smaller positively charged hydrogen atoms as Mickey's ears.
      The positively charged end of the water molecule tries to align itself with the microwave's electric field while the negatively charged end points the other way. But because the field reverses 2.5 billion times a second, Mickey's ears and face are being twisted back and forth rapidly.
      As the molecules twist back and forth, they rub into each other. This creates friction, which produces heat.

      --Louis Bloomfield, a professor of physics at the University of Virginia
      (A professor in physics in more knowledgeable in this matter than anyone here and WikiPedia put together)