RALEIGH, N.C. (WNCN) – People lately have become concerned with cellphones and whether or not they carry health risks.
There are a few reasons why people have become worried of cellphone health risks. For one, cellphones emit radio frequency energy from their antennas. The tissues nearest the phones can absorb this energy and we do not know what these effects may be.
Ionizing radiation, such as that from a chest x-ray, is known to be associated with an increased risk for cancer, non-ionizing radiation such as that from cellphones has not been shown to cause cancer at this point in humans.
A new study, presented late last week, suggests that there is a link between exposure to the radiation produced by cellphones and certain types of cancers in rats. These rats were exposed to particular frequencies of radiation that we see from cellphones, on a daily basis in a controlled environment.
The rats developed tumors in both the brain and heart—albeit at a very low rate. The tumor types were gliomas in the brain and schwannomas (a nerve sheath tumor almost never seen in the heart).
The study explored effects from the most common type of wireless technologies, GSM and CDMA, at two common frequencies, 900 megahertz for rats and 1900 megahertz for mice. It exposed the rats to the frequencies every 10 minutes followed by a 10-minute break for 18 hours, resulting in nine hours a day of exposure.
There are issues with the study—the data is probably not able to be generalized. The first thing to note is that this is a study in an animal model—findings in animals are not always directly translatable to man. Other large observational studies in humans have found no direct link between cellphone use and cancer. Other studies have produced conflicting results.
A study in Denmark looked at 358,000 cellphone users and then compared their cancer rates to brain-tumor data from a national cancer registry. That study did not find a link between the two. Another recent study published in May looked at incidence of brain cancer in Australia from 1982 to 2013 and did not find an uptick in cancer cases with the introduction of cells phones.
There are some other interesting points from the study—first of all these findings are likely to lead to further study in humans. At this point, they should not lead to any type of comprehensive statement on risk in humans nor should it lead to regulation.
Several major questions and caveats are raised by the new study.
The control group had no tumors—even though it is known that this type of rat develops brain tumors spontaneously at a low rate. If the controls had had a more credible 2 percent rate, the result for brain cancer would no longer be significant. Another issue that is difficult to explain is that the tumors were manly in male rats—which also draws the conclusions of the study into question.
It is important to take these findings with a grain of salt, studies like this are quite often sensationalized and supported only by a few of the scientists who have a vested interest in the findings.
For me, the bottom line is—at this point we still do not have compelling evidence that cellphones cause cancer in humans. We do have large data sets from observational trials that suggest no link at all. More study is required.
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