User's Manual

78
For Your Safety
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.