
242
Safety
2000. Between them, the stud ies investigated any possib le association
between the use of wirele ss phones and primar y brain cancer, glioma,
meningioma, or acousti c neuroma, tumors of the brai n or salivary
gland, leukemia, or other cancers. None of the studies demonstrated
the existence of any harmful h ealth effects from wire less phone RF
exposures. However, none of the studies ca n answer questions about
long-term exposures, since t he average period of phone use i n these
studies was around three year s.
kWhat research is n eeded to decide wheth er RF exposure from wir eless phones poses a hea lth risk?A combination of laborator y studies and epidemio logical studies of
people actually using w ireless phones would prov ide some of the
data that are needed. Lifeti me animal exposure studie s could be
completed in a few years. However, very lar ge numbers of animals
would be needed to provide reli able proof of a cancer promotin g effect
if one exists. Epidemiolo gical studies can provid e data that is directly
applicable to human popu lations, but 10 or more years’ follow-up may
be needed to provide answer s about some health effe cts, such as
cancer. This is because the inte rval between the time of exp osure to a
cancer-causing agent and t he time tumors develop—if they do—may
be many, many years. The interpretatio n of epidemiological stu dies is
hampered by difficu lties in measuring actu al RF exposure during day-
to-day use of wireless phone s. Many factors affect this me asurement,
such as the angle at which th e phone is held, or which mode l of phone
is used.
kWhat is FDA doing to find o ut more about the possible healt h effects of wireles s phone RF?FDA is working with the U.S. National Toxicol ogy Program and with
groups of investigators around th e world to ensure that high prior ity