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There were no changes in the subjects’ ability to recall words, numbers, or pictures,
or in their spatial memory, but they were able to make choices more quickly in one
visual test when they were exposed to simulated mobile phone signals. This was the
only change noted among more than 20 variables compared.
3
2. In a study of 209 brain tumor cases and 425 matched controls, there was no
increased risk of brain tumors associated with mobile phone use. When tumors did
exist in certain locations, however, they were more likely to be on the side of the head
where the mobile phone was used. Because this occurred in only a small number of
cases, the increased likelihood was too small to be statistically significant.
4
In summary, we do not have enough information at this point to assure the public
that there are, or are not, any low incident health problems associated with use of
mobile phones. FDA continues to work with all parties, including other federal agen-
cies and industry, to assure that research is undertaken to provide the necessary
answers to the outstanding questions about the safety of mobile phones.
What is known about cases of human cancer that have been reported
in users of hand-held mobile phones?
Some people who have used mobile phones have been diagnosed with brain cancer.
But it is important to understand that this type of cancer also occurs among people
who have not used mobile phones. In fact, brain cancer occurs in the U.S. population
at a rate of about 6 new cases per 100,000 people each year. At that rate, assuming 80
million users of mobile phones (a number increasing at a rate of about 1 million per
month), about 4800 cases of brain cancer would be expected each year among those
80 million people, whether or not they used their phones. Thus it is not possible to
tell whether any individual's cancer arose because of the phone, or whether it would
have happened anyway. A key question is whether the risk of getting a particular form
of cancer is greater among people who use mobile phones than among the rest of the
population. One way to answer that question is to compare the usage of mobile
phones among people with brain cancer with the use of mobile phones among
appropriately matched people without brain cancer.
When 20 types of glioma were considered separately, however, an association was
found between mobile phone use and one rare type of glioma, neuroepithelliomatous
tumors. It is possible with multiple comparisons of the same sample that this associ-
ation occurred by chance. Moreover, the risk did not increase with how often the
mobile phone was used, or the length of the calls. In fact, the risk actually decreased
with cumulative hours of mobile phone use. Most cancer causing agents increase risk
with increased exposure. An ongoing study of brain cancers by the National Cancer
Institute is expected to bear on the accuracy and repeatability of these results.
1
2. Researchers conducted a large battery of laboratory tests to assess the effects of
exposure to mobile phone RF on genetic material. These included tests for several
kinds of abnormalities, including mutations, chromosomal aberrations, DNA strand
breaks, and structural changes in the genetic material of blood cells called lympho-
cytes. None of the tests showed any effect of the RF except for the micronucleus assay,
which detects structural effects on the genetic material. The cells in this assay showed
changes after exposure to simulated cell phone radiation, but only after 24 hours of
exposure. It is possible that exposing the test cells to radiation for this long resulted
in heating. Since this assay is known to be sensitive to heating, heat alone could have
caused the abnormalities to occur. The data already in the literature on the response
of the micronucleus assay to RF are conflicting. Thus, follow-up research is neces-
sary.
2
FDA is currently working with government, industry, and academic groups to ensure
the proper follow-up to these industry-funded research findings. Collaboration with
the Cellular Telecommunications Industry Association (CTIA) in particular is expect-
ed to lead to FDA providing research recommendations and scientific oversight of new
CTIA-funded research based on such recommendations.
Two other studies of interest have been reported recently in the literature:
1. Two groups of 18 people were exposed to simulated mobile phone signals under
laboratory conditions while they performed cognitive function tests.
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