252
Chapter 16. Safety and warranty
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.
FDA CONSUMER UPDATE
