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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 do not 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 ten 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
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