Siemens sx56 User Manual page 109

was also no association between mobile phone use and gliomas when all types of gliomas were con-
sidered together. It should be noted that the average length of mobile phone exposure in this study was
less than three years.
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 association 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.
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 lymphocytes. 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 necessary.
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 expected 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:
•
Two groups of 18 people were exposed to simulated mobile phone signals under laboratory condi-
tions while they performed cognitive function tests. 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.
•
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.
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 agencies 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
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