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causing chemicals so as to be pre-disposed 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 long-
term exposures, since the average period of phone use in
these studies was around three years.
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 day-to-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 the FDA doing to find out more about the
possible health effects of wireless phone RF?
The 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 Radio Frequency energy (RF).
The 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. The FDA
and the Cellular Telecommunications & Internet
Association (CTIA) have a formal Cooperative Research
and Development Agreement (CRADA) to do research on
wireless phone safety. The FDA provides the scientific
oversight, obtaining input from experts in government,
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