Life Bluetube Headsets
Cell Phone Towers Health Effects
EM Field Meter
Cell Phone Sensitivity
The final results of a major international study of the
potential link between cellphone use and cancer were
published last week. The finding: Using a cellphone seems to
protect against two types of brain tumors.
Even the researchers didn't quite believe it.
The apparent shield of cellphone radiation, most likely
fictitious, illustrates how hard it is to analyze, let alone
quantify, the potential for a small elevated risk in a rare
disease from a widespread, mundane activity.
"They found that ever having used a cellphone appeared to be
protective [against] brain cancer," says David O. Carpenter,
director of the University at Albany's Institute for Health
and the Environment, in Albany, N.Y. "And that just simply
makes no sense."
The study was funded in part by the Mobile Manufacturers'
Forum and GSM Association, two wireless industry groups. The
researchers had protections in place they say guarded their
independence. Most criticisms of the study haven't focused
on the funding.
The researchers conducting the study, which was called
Interphone, were flummoxed at nearly every turn. They tried
to find a control group that matched participants who had
suffered a brain tumor, but potential subjects were
reluctant to participate, for various reasons. Then there
were subtle behavioral differences between individuals with
and without brain tumors. Internal squabbling over how to
interpret the results delayed publication for so long that
usage patterns of study participants didn't match those of
mobile users today.
The Interphone researchers acknowledged in their resulting
paper, published online last week by the International
Journal of Epidemiology, that something had probably gone
wrong with the controls.
The study tracked cellphone use across 13 countries. It
looked at a group of adults 30 to 59 years old who had been
diagnosed with glioma or meningioma, types of brain tumors
that can be either benign or malignant, between 2000 and
2004. They were compared with control subjects, people
selected to match the individuals with tumors in terms of
age, gender and place of residence.
Then both groups were interviewed extensively about their
cellphone use. If the two groups matched in other ways, and
the group with brain tumors used cellphones more frequently,
that would suggest that cellphone use might have caused the
But they didn't really match. For one thing, just 53% of
people selected to participate as controls agreed, and a
survey of those who declined showed that they were less
likely to use cellphones than those who participated. That
may have artificially raised cellphone use in the tumor-free
control group and made mobile phones seem less dangerous
than they are.
The result is a strange set of numbers. Many levels of
cellphone use appeared to reduce the chance of developing a
tumor. Only the people who talked on cellphones the most had
a significantly greater chance of developing glioma—40%
greater—than those who didn't use cellphones.
Yet, as some of the study's authors themselves pointed out,
if those who never used cellphones—who were more prevalent
among those with tumors—were excluded, and the lightest
users were contrasted with the more avid ones, then the
bizarre protective effect of cellphone use mostly
disappeared, and the risk among the heaviest users was 82%
Even in this analysis, the risk doesn't steadily increase
with use, which is what epidemiologists typically look for—a
discernible dose-response relationship. "It's certainly less
compelling than if you saw some kind of graded response,"
says David A. Savitz, director of the Disease Prevention and
Public Health Institute at the Mount Sinai School of
Medicine in New York.
Disputes about how to interpret these numbers held up
publication of the research, says Christopher Wild, director
of the World Health Organization's International Agency for
Research on Cancer, in Lyon, which coordinated the study.
The study was published more than six years after its
conclusion, by which time cellphone use had both surged and
"Interphone made more effort than most other studies to
identify and quantify its own flaws," says co-author Martine
Vrijheid, a researcher at the agency. "It has thereby also
attracted more attention to these flaws."
A U.K. study under way will take a different approach,
tracking cellphone users over time to see if heavy use is
tied to a greater incidence of cancer. But the study will
still need to enlist hundreds of thousands of volunteers to
yield useful results, and it could take decades to spot any
divergence in cancer rates.
Epidemiologists say such research may be difficult and
expensive but is important.
"Even if you think it's very, very unlikely that it's a
problem," Dr. Savitz says, "it's always worth some effort to
make sure you haven't done something really terrible" as a
society by enabling widespread cellphone use. Such open
questions, and the difficulty of solving them, he says,
"keep epidemiologists in business for a long time."
Czech Republic, Prague
Guatemala, Guatemala City
Charters Towers, Queensland, Australia
Congo, Democratic Republic of the Kinshasa