80 VX5400
Safety
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 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