4. What are the results of the research done already?
The research done thus far has produced conflicting results, and many studies have
suffered from flaws in their research methods. Animal experiments investigating
the effects of radiofrequency energy (RF) exposures characteristic of wireless
phones have yielded conflicting results that often cannot be repeated in other
laboratories. A few animal studies, however, have suggested that low levels of RF
could accelerate the development of cancer in laboratory animals. However, many
of the studies that showed increased tumor development used animals that had
been genetically engineered or treated with cancer causing chemicals so as to
be predisposed 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 don't 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 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.
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