Table of Contents
Advertisement
16
Regulatory Statements
The U.S. Food and Drug Administration's Center for Devices and
Radiological Health, Consumer Update on Mobile Phones
FDA has been receiving inquiries about the safety of
mobile phones, including cellular phones and PCS
phones. The following summarizes what is known—
and what remains unknown—about whether these
products can pose a hazard to health, and what can
be done to minimize any potential risk. This
information may be used to respond to questions.
Why the concern?
Mobile phones emit low levels of radiofrequency
energy (i.e. radiofrequency radiation) in the
microwave range while being used. They also emit
very low levels of radiofrequency energy (RF),
considered non-significant, when in the stand-by
mode. It is well known that high levels of RF can
produce biological damage through heating effects
(this is how your microwave oven is able to cook
food). However, it is not known whether, to what
extent, or through what mechanism, lower levels of
RF might cause adverse health effects as well.
Although some research has been done to address
these questions, no clear picture of the biological
effects of this type of radiation has emerged to date.
Thus, the available science does not allow us to
conclude that mobile phones are absolutely safe, or
that they are unsafe. However, the available scientific
evidence does not demonstrate any adverse health
effects associated with the use of mobile phones.
What kinds of phones are in question?
Questions have been raised about hand-held mobile
phones, the kind that have a built-in antenna that is
positioned close to the user's head during normal
telephone conversation. These types of mobile
phones are of concern because of the short distance
between the phone's antenna—the primary source
of the RF— and the person's head. The exposure to
RF from mobile phones in which the antenna is
located at greater distances from the user (on the
outside of a car, for example) is drastically lower than
that from hand-held phones, because a person's RF
exposure decreases rapidly with distance from the
source. The safety of so-called "cordless phones,"
which have a base unit connected to the telephone
wiring in a house and which operate at far lower
power levels and frequencies, has not been
questioned.
How much evidence is there that hand-held
mobile phones might be harmful?
Briefly, there is not enough evidence to know for
sure, either way; however, research efforts are on-
going. The existing scientific evidence is conflicting
and many of the studies that have been done to date
have suffered from flaws in their research methods.
Animal experiments investigating the effects of RF
exposures characteristic of mobile phones have
yielded conflicting results. A few animal studies,
however, have suggested that low levels of RF could
accelerate the development of cancer in laboratory
animals. In one study, mice genetically altered to be
predisposed to developing one type of cancer
developed more than twice as many such cancers
when they were exposed to RF energy compared to
controls. There is much uncertainty among scientists
about whether results obtained from animal studies
apply to the use of mobile phones. First, it is
uncertain how to apply the results obtained in rats
and mice to humans. Second, many of the studies
that showed increased tumor development used
animals that had already been treated with cancer-
causing chemicals, and other studies exposed the
animals to the RF virtually continuously—up to 22
hours per day.
For the past five years in the United States, the mobile
phone industry has supported research into the
safety of mobile phones. This research has resulted
in two findings in particular that merit additional
study:
1
In a hospital-based, case-control study,
researchers looked for an association between
mobile phone use and either glioma (a type of
brain cancer) or acoustic neuroma (a benign
tumor of the nerve sheath). No statistically
significant association was found between mobile
phone use and acoustic neuroma. There was also
no association between mobile phone use and
gliomas when all types of types of gliomas were
considered together. It should be noted that the
average length of mobile phone exposure in this
study was less than three years.
When 20 types of glioma were considered
separately, however, an association was found
between mobile phone use and one rare type of
glioma, neuroepithelliomatous tumors. It is
possible with multiple comparisons of the same
sample that this association occurred by chance.
Moreover, the risk did not increase with how often
the mobile phone was used, or the length of the
[[[
]]]
47
16
Advertisement
Table of Contents
