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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 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:
1
Two groups of 18 people were exposed to
simulated mobile phone signals under
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