Motorola V2267 Introduction Manual page 74

How much evidence is there that hand-held mobile
phones might be harmful?
Briefly, there is not enough evidence to know for sure, either
way; however, research efforts are on-going. The existing
scientific evidence is conflicting and many of the studies that
have been done to date have suffered from flaws in their
research methods. Animal experiments investigating the effects
of RF exposures characteristic of mobile phones have yielded
conflicting results. A few animal studies, however, have
suggested that low levels of RF could accelerate the development
of cancer in laboratory animals. In one study, mice genetically
altered to be predisposed to developing one type of cancer
developed more than twice as many such cancers when they
were exposed to RF energy compared to controls. There is much
uncertainty among scientists about whether results obtained
from animal studies apply to the use of mobile phones. First, it is
uncertain how to apply the results obtained in rats and mice to
humans. Second, many of the studies that showed increased
tumor development used animals that had already been treated
with cancer-causing chemicals, and other studies exposed the
animals to the RF virtually continuously--up to 22 hours per day.
For the past five years in the United States, the mobile phone
industry has supported research into the safety of mobile phones.
This research has resulted in two findings in particular that merit
additional study:
1 In a hospital-based, case-control study, researchers looked for
an association between mobile phone use and either glioma (a
type of brain cancer) or acoustic neuroma (a benign tumor of
the nerve sheath). No statistically significant association was
found between mobile phone use and acoustic neuroma.
There was also no association between mobile phone use and
gliomas when all types of types of gliomas were considered
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U.S. Food and Drug Administration (FDA)
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
1
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.
2