Study:
Some cell phone users at risk for benign tumor
STOCKHOLM,
Sweden (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 report said.
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 handsfree
set," he said.
