NEW YORK (Reuters Health) - The
heaviest users of cell phones may be at higher than average risk of
being diagnosed with a brain tumor, according to a recent French study.
But for most people, it’s still not clear if there’s
added risk, the authors say. Plus, the devices and the way people
use them keeps evolving so that more research is needed going
forward, they add.
This isn’t the first study to point to a tumor risk with heavy cell
phone use, said Dr. L. Dade Lunsford, a distinguished professor of
neurosurgery specializing in brain tumor management at the
University of Pittsburgh.
But these kinds of studies rely on people to recall how much they
have used cell phones in the past with no indication of their actual
use, said Lunsford, who was not involved in the French research.
The new results found no difference between regular cell users and
non-users, which suggests that if there is a link, it is only
applicable for people who claim to use their cell phone the most, he
noted by email.
Cell phones emit radiofrequency electromagnetic fields in the
microwave spectrum, which may be cancer causing, although that’s not
yet proven, said Dr. Seung-Kwon Myung of South Korea's National
Cancer Center.
Myung led a large analysis of all the previous studies of cell phone
use and brain tumors (see Reuters article of October 13, 2009 here:
http://reut.rs/1tlL8JZ).
In 2011, the World Health Organization’s International Agency on
Cancer classified this radiation as possibly carcinogenic, based on
existing studies.
The French team, led by Dr. Gaelle Coureau of the Universite
Bordeaux Segalen, used a cancer registry to identify adults with
meningiomas or gliomas, the two most common types of adult brain
tumors.
Brain tumors are generally rare relative to other types of cancer.
Less than eight in 100,000 people in the U.S. each year are
diagnosed with meningiomas, and 85 percent of those tumors are
benign, according to Johns Hopkins Medicine and the Cleveland
Clinic.
Malignant brain tumors represent only two percent of all cancers.
The new analysis included 253 cases of glioma and 194 cases of
meningioma in four French regions, and twice as many people from the
same areas of France who had never had a brain tumor, for
comparison.
Researchers interviewed the participants about their past cell phone
use, with questions about the model of phone they had used, how long
they had used it, the average number and length of calls made and
received each month and whether the phones were used for work.
“Regular users,” who had used a mobile phone at least once a week
for at least six months at a time, were no more likely to have a
tumor than those who had never used a cell phone, according to the
results published in Occupational and Environmental Medicine.
People with the longest cumulative duration of calls, or more than
896 hours on the phone, were about twice as likely to have a glioma
or meningioma than people who had talked less.
“Case-control studies use questionnaires to ask people to recall how
often they used their phones for periods up to 10 years and more,”
said Dr. Michael Repacholi, former coordinator of the World Health
Organization Electromagnetic Field (EMF) Project. “Most people could
not accurately remember how many calls or for how long they used
their phone each call 10 years ago, and so they give best
estimates.”
Cancer registries have not shown a significant increase in brain
cancers since mobile technology was introduced 20 years ago, which
is reassuring, Repacholi said.
Mobile phone users shouldn’t worry too much about this problem until
larger, better studies have been done, and those will take at least
another 10 years, Myung told Reuters Health by email.
The new French study will not affect the world’s conversion to
mobile phone use, which has saved more lives across the world than
probably any other technology in the last 100 years, Lunsford said.
“The ability to communicate without land line access to report
illness, injury, impending weather disasters, to access 911, fire,
police has undoubtedly saved more lives than any conceivable risk of
the late and as yet unverified risk of exposure to non ionizing
radiation from mobile phones,” he said.
To minimize the risk, if there is any, Myung recommends following
five safety tips issued by the Environmental Working Group: use a
headset or speakerphone when possible, when in use hold the phone
away from your body, text instead of calling, don’t store the phone
in your pocket or under your pillow and try only to use it when you
have a strong signal.
“Fewer signal bars means the phone must try harder to broadcast its
signal,” he said. “Research shows that radiation exposure increases
dramatically when cell phone signals are weak.”
SOURCE: http://bit.ly/1h9B7bv
Occupational and Environmental Medicine, online May 9, 2014.
