Dialing Up a Tumor on Your Cell Phone
Medical Authors and Editors:
Barbara K. Hecht,
Ph.D. and
Frederick Hecht, M.D.
October 15, 2004 -- Ten or more years of mobile phone use has been found to
increase the risk of a tumor called acoustic neuroma. The risk appears confined
to the side of the head where the phone is usually held.
This worrisome information is in a report of a study from
the Institute of Environmental Medicine at the famed Karolinska Institute in Stockholm. There is
no evidence for an increased risk with less than 10 years of mobile phone use.
Acoustic Neuroma
Acoustic neuromas are slow-growing benign tumors of the acoustic nerve, the
eighth cranial nerve, which is responsible for balance and head position as well
as hearing.
Radiofrequency exposure from mobile phones is concentrated to the tissues
closest to the handset, which includes the auditory nerve. If this type of
exposure increases tumor risk, acoustic neuroma would be a potential concern.
The Swedish Study
A total of about 150 acoustic neuroma patients and 600 healthy controls
participated in a case-control study.
The risk of acoustic neuroma was found to be almost double for people who
started using their analog cell phone at least 10 years before the diagnosis of
their tumor.
When the side of the head on which the phone was usually held was taken into
consideration, it was found that the risk of acoustic neuroma almost quadrupled
on the phone side and was virtually normal on the other side.
Limitations of the
Study
This study was retrospective and had the same significant limitations as do
all retrospective studies. From the start it was already known who did or did
not have an acoustic neuroma. New patients treated for acoustic neuroma in
"certain parts of Sweden" were in the study.
The sample may have been biased in other ways. A nurse contacted the patients
and controls and asked them if they wanted to participate and only those who
said "yes" were included in the study.
Those who agreed to participate in the study then had a personal interview
about their mobile phone use and other issues of importance in the study.
Analog
Only
At the time the study was done, only analog phones had been in use for 10
years or more, so the study was confined to them. Whether the results would be
similar or not after long-term use of digital (GSM) phones is not known.
Although the study has its limitations, the basic conclusion it comes to
looks solid to us. It casts light not only on the danger of using an analog cell
phone but also on the genesis of acoustic neuromas.
What is Happening
Acoustic neuroma is best known as the hallmark of a genetic disorder known as
neurofibromatosis-2. In this disorder, a heritable mutation results in loss of
function of a gene on chromosome 22. That gene normally
controls the growth of Schwann cells, small sheet-like cells that grow around
nerve fibers like onion skin and help support the nerve.
We would think that what is happening is that
radiofrequency exposure from analog cell phones is mutating this same gene on
chromosome 22, causing it to lose function and fail to control the growth of Schwann cells, and the end
result is an acoustic neuroma.
Reference:
Lonn S, et al: Mobile Phone Use and the Risk of Acoustic
Neuroma. Epidemiology 15::653, Nov 2004
Last Editorial Review: 10/15/2004
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