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U.S. FDA
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date: 040413
left page (74)
of CF62 Leopard TMO SUG us, A31008-H6050-A40-1-4A19 (02.06.2004, 16:08)
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; how-
ever, 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 inves-
tigating the effects of RF exposures
characteristic of mobile phones have
yielded conflicting results. A few ani-
mal studies, however, have sug-
gested that low levels of RF could
accelerate the development of can-
cer 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 ani-
mal 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 showed
increased tumor development used
animals that had already been
treated with cancer-causing chemi-
cals, and other studies exposed the
animals to the RF virtually continu-
ously – 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 neu-
roma. There was also no association
between mobile phone use and glio-
mas when all 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 con-
sidered 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 caus-
ing agents increase risk with
increased exposure. An ongoing
study of brain cancers by the
