The U.S. Food and Drug Administration's Center for Devices and Radiological Health Consumer Update
which have a base unit connected to the telephone
wiring in a house and which operate at far lower
power levels and frequencies, has not been
questioned.
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 together. It should be noted that the
average length of mobile phone exposure in this
study was less than three years.
2 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
