Appendix
174
medical device manufacturers, and many other
groups, was completed in late 2000. This standard
will allow manufacturers to ensure that cardiac
pacemakers and defibrillators are safe from wireless
phone EMI.
FDA has tested hearing aids for interference from
handheld wireless phones and helped develop a
voluntary standard sponsored by the Institute of
Electrical and Electronic Engineers (IEEE). This
standard specifies test methods and performance
requirements for hearing aids and wireless phones
so that no interference occurs when a person uses a
compatible phone and a compatible hearing aid at
the same time. This standard was approved by the
IEEE in 2000.
FDA continues to monitor the use of wireless
phones for possible interactions with other medical
devices. Should harmful interference be found to
occur, FDA will conduct testing to assess the
interference and work to resolve the problem.
10.What are the results of the research done
already?
The research done thus far has produced conflicting
results, and many studies have suffered from flaws
in their research methods. Animal experiments
investigating the effects of radio frequency energy
(RF) exposures characteristic of wireless phones
have yielded conflicting results that often cannot be
repeated in other laboratories. A few animal
studies, however, have suggested that low levels of
RF could accelerate the development of cancer in
laboratory animals. However, many of the studies
that showed increased tumor development used
animals that had been genetically engineered or
treated with cancer causing chemicals so as to be
pre-disposed to develop cancer in the absence of RF
Appendix
175
exposure. Other studies exposed the animals to RF
for up to 22 hours per day. These conditions are not
similar to the conditions under which people use
wireless phones, so we don t know with certainty
what the results of such studies mean for human
health.
Three large epidemiology studies have been
published since December 2000. Between them, the
studies investigated any possible association
between the use of wireless phones and primary
brain cancer, gioma, meningioma, or acoustic
neuroma, tumors of the brain or salivary gland,
leukemia, or other cancers. None of the studies
demonstrated the existence of any harmful health
effects from wireless phone RF exposures.
However, none of the studies can answer questions
about long-term exposures, since the average
period of phone use in these studies was around
three years.
11.What research is needed to decide whether RF
exposure from wireless phones poses a health
risk?
A combination of laboratory studies and
epidemiological studies of people actually using
wireless phones would provide some of the data
that are needed. Lifetime animal exposure studies
could be completed in a few years. However, very
large numbers of animals would be needed to
provide reliable proof of a cancer promoting effect if
one exists. Epidemiological studies can provide data
that is directly applicable to human populations, but
10 or more years follow-up may be needed to
provide answers about some health effects, such as
cancer. This is because the interval between the
time of exposure to a cancer-causing agent and the
time tumors develop - if they do - may be many,
