For Your Safety 135
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 Radio Frequency (RF) energy 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 pre-disposed 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 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.
