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What kinds of phones are the subject of this
update?
The term “wireless phones” refers here to hand-held wireless
phones with built-in antennas, often called “cell,” “mobile,” or
“PCS”. These types of wireless phones can expose the user to
measurable radio frequency energy (RF) because of the short
distance between the phone and the user’s head. These RF
exposures are limited by Federal Communications
Commission safety guidelines that were developed with the
advice of FDA and other federal health and safety agencies.
When the phone is located at greater distances from the user,
the exposure to RF is drastically lower because a person’s RF
exposure decreases rapidly with increasing distance from the
source. The so-called “cordless phones” which have a base
unit connected to the phone wiring in a house, typically
operate at far lower per levels, and thus produce RF
exposures far below the FCC safety limits.
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 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 pre-disposed to develop cancer in 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
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under which people use wireless phones, so we don’t know
with certainty what 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, glaucoma, 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 phones
RF exposures. However, none of the studies can answer
questions about long-term exposures, since average period of
phone use in these studies was around three years.
What research is needed to decide whether RF
exposure from wireless phones poses a health
threat?
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.
Summary of Contents for SGH-P716
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