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.
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