(AP) A Swedish study suggests that people who use a cell phone for
at least 10 years might increase their risk of
developing a rare benign tumor along a nerve on the side
of the head where they hold the phone.
In an interview Thursday with The Associated Press, one
of the researchers behind the preliminary study, Anders
Ahlbom, said the results were surprising and more
research is needed.
Several previous studies have investigated whether the
use of cell phones is linked to an increased risk of
brain tumors. Although experiments have shown radiation
from mobile phones can affect brain cells in a lab, more
relevant studies on people have found no evidence that
the phones pose a health risk. However, experts have
said that because children's brains are developing, it
may not be a good idea for youngsters to use the phones
for long periods.
The three-year study by Ahlbom and Maria Feychting,
professors at the Karolinska Institutet in Stockholm,
focused on 750 Swedes who had used cell phones for at
least 10 years. It was published in the International
Journal of Epidemiology.
In the study, researchers questioned 150 patients
already diagnosed with acoustic neuroma, a benign tumor
on the auditory nerve that takes several years to grow
before being diagnosed, and 600 who did not have it,
about their cell phone use.
All 750 subjects had been using cell phones for at least
10 years, nearly all early analog models that emit more
electromagnetic radiation than the digital models now on
the market. Digital phones emit radiation in pulses; the
older analog varieties emit continuous waves. Since cell
phones exploded in popularity in the late 1990s, most of
those sold used digital technology.
"At the time the study was conducted, only analog mobile
phones had been in use for more than 10 years and
therefore we cannot determine if the results are
confined to use of analog phones or if the results would
be similar after long-term use of digital phones," the
The risk of developing a tumor was almost double for
those who started to use phones before their diagnosis.
In addition, the tumor risk was almost four times higher
on the side of the head where the phone was held, Ahlbom
and Feychting said.
Retrospective questionnaires are not considered the most
accurate method of determining a link between behavior
and disease. Many links that emerge from such studies
turn out not to be true under more rigorous study.
Acoustic neuroma tumors, which can affect hearing, occur
in less than one adult per 100,000 people annually. The
tumor pushes on the surface of the brain, but doesn't
grow into the brain itself, according to the
Atlanta-based Acoustic Neuroma Association.
The study was funded by the European Union and is part
of the wider Interphone study coordinated by the
International Agency for Research on Cancer.
Previous studies, including one by Finnish scientists in
2002, found that electromagnetic radiation emitted by
phones can affect brain tissue, but others have said
that's not the case.
The wireless industry has always maintained there is no
link between mobile phones and cancer.
The Wireless Association in Washington, D.C., a trade
group representing American cell phone manufacturers,
urged more research. "The wireless industry agrees that
more research is needed in this area to provide
definitive answers to any questions that might still
exist," it said in a statement Wednesday.
Ahlbom conceded more research was needed, adding the
study was not an excuse to avoid using cell phones. "You
could say also, of course, if that someone is concerned
about these results the easy way to avoid any risk is to
use a hands-free set," he said.