5. 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, many
years. The interpretation of epidemiological studies is
hampered by difficulties in measuring actual RF
exposure during dayto- day use of wireless phones.
Many factors affect this measurement, such as the
angle at which the phone is held, or which model
of phone is used.
6. What is FDA doing to find out more about the
possible health effects of wireless phone RF?
FDA is working with the U.S. National Toxicology
Program and with groups of investigators around the
world to ensure that high priority animal studies are
conducted to address important questions about the
effects of
exposure to radiofrequency energy (RF).
FDA has been a leading participant in the World
Health Organization International Electromagnetic
Fields (EMF) Project since its inception in 1996. An
influential result of this work has been the
development of a detailed agenda of research needs
that has driven the establishment of new research
programs around the world. The Project has also
helped develop
a series of public information documents on EMF
issues. FDA and the Cellular Telecommunications
& Internet Association (CTIA) have a formal
Cooperative Research and Development Agreement
(CRADA) to
do research on wireless phone safety.
FDA provides the scientific oversight, obtaining input
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the user, the exposure to RF is drastically lower
because a person's RF exposure decreases rapidly
with increasing distance from the source. The so-
called “cordless phones,” which have a base unit
connected to the phone wiring in a house, typically
operate at far lower power levels, and thus produce RF
exposures far below
the FCC safety limits.
4. 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 radiofrequency 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 predisposed to develop cancer
in the absence of RF 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, glioma,
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
longterm exposures, since the average period of
phone use in these studies was
around three years.
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