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U.S. FDA
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, re-
search 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 de-
velopment of cancer in laboratory ani-
mals. In one study, mice genetically al-
tered 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 un-
certain 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 chemicals, and other studies ex-
posed 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 result-
ed in two findings in particular that
merit additional study:
1. In a hospital-based, case-control study,
researchers looked for an association be-
tween mobile phone use and either glio-
ma (a type of brain cancer) or acoustic
neuroma (a benign tumor of the nerve
sheath). No statistically significant associ-
ation was found between mobile phone
use and acoustic neuroma. There was also
no association between mobile phone use
and gliomas 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 consid-
ered separately, however, an association
was found between mobile phone use
and one rare type of glioma, neuroepi-
thelliomatous tumors. It is possible with
multiple comparisons of the same sam-
ple that this association occurred by
chance. Moreover, the risk did not in-
crease with how often the mobile phone
was used, or the length of the calls. In
fact, the risk actually decreased with cu-
mulative 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
1
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 sever-
al kinds of abnormalities, including mu-
tations, chromosomal aberrations,