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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 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.
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.
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
Section 4A: Safety
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