Safety
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.
98
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.