Senior Citizens May
Have Been Smart to Delay on Cell Phones: Use May Effect Brain
Study finds mobile
phones
do effect brain activity but consequences unknown - see video
Feb. 22, 2011
Senior citizens, the age group that has been the slowest to adapt to
cell phone use, may have been right in exercising caution, suggests a
new study. The report in the February 23 issue of the Journal of the
American Medical Association says 50 minutes of cell phone use increased
brain activity in the region closest to the phne antenna.
The low-level
radiation from the phone increased the brain glucose metabolism, which
is a marker for brain activity. Consumer Reports also published a report
in January on this topic - How risky is cell-phone radiation? See
more about the CR report below this news story.
"The dramatic
worldwide increase in use of cellular telephones has prompted concerns
regarding potential harmful effects of exposure to radio
frequency-modulated electromagnetic fields (RF-EMFs), say the authors
of the report in JAMA.
Of particular
concern, they say, has been the potential carcinogenic effects from
the RF-EMF emissions of cell phones. However, epidemiologic studies of
the association between cell phone use and prevalence of brain tumors
have been inconsistent (some, but not all, studies showed increased
risk), and the issue remains unresolved."
These researchers
were also motivated to pursue the study because studies performed in
humans to investigate the effects of RF-EMF exposures from cell phones
have yielded variable results, highlighting the need for studies to
document whether RF-EMFs from cell phone use affects brain function in
humans.
The randomized
study, conducted between January 1 and December 31, 2009, by Nora D.
Volkow, M.D., of the National Institutes of Health, Bethesda, Md., and
colleagues, was aimed at determining if cell phone exposure affected
regional activity in the human brain. It included 47 participants.
Cell phones were
placed on the left and right ears and brain imaging was performed with
positron emission tomography (PET) with fluorodeoxyglucose injection,
used to measure brain glucose metabolism twice - once with the right
cell phone activated (sound muted) for 50 minutes ("on" condition) and
once with both cell phones deactivated ("off" condition).
Analysis was
conducted to verify the association of metabolism and estimated
amplitude of radiofrequency-modulated electromagnetic waves emitted by
the cell phone. The PET scans were compared to assess the effect of cell
phone use on brain glucose metabolism.
The researchers
found that whole-brain metabolism did not differ between the on and off
conditions.
However, there
were significant regional effects. Metabolism in the brain region
closest to the antenna (orbitofrontal cortex and temporal pole) was
significantly higher (approximately 7 percent) for cell phone on than
for cell phone off conditions.
"The increases
were significantly correlated with the estimated electromagnetic field
amplitudes both for absolute metabolism and normalized metabolism," the
authors write.
"This indicates
that the regions expected to have the greater absorption of RF-EMFs from
the cell phone exposure were the ones that showed the larger increases
in glucose metabolism."
"These results
provide evidence that the human brain is sensitive to the effects of
RF-EMFs from acute cell phone exposures," the researchers write. They
add that the mechanisms by which RF-EMFs could affect brain glucose
metabolism are unclear.
"Concern has been
raised by the possibility that RF-EMFs emitted by cell phones may induce
brain cancer. ... Results of this study provide evidence that acute cell
phone exposure affects brain metabolic activity. However, these results
provide no information as to their relevance regarding potential
carcinogenic effects (or lack of such effects) from chronic cell phone
use."
"Further studies
are needed to assess if these effects could have potential long-term
harmful consequences," the authors conclude.
Consumer
Reports expert says test conservative
Michael Hansen,
Ph.D., a senior scientist at Consumer Reports, notes that the
test used in the study was fairly conservative, since people werent
talking during the test, notes the senior editor of Consumers Report,
Doug Podolsky, in a
blog today.
Radiation
increases when the cell phone is sending an audible signal, and also
when youre talking, said Hansen. So this study mimics simply
listening to a muted voice for 50 minutes. Thats not normal cell phone
use, unless you have a very talkative friend and you have laryngitis.
Podolsky also
reports, Some observational research has suggested that some cell-phone
users might have a slightly increased risk of certain types of brain
tumors. But a spokeswoman for the Food and Drug Administration said in
an e-mail that the Agency evaluates the weight of scientific evidence,
and concluded that heating is the only confirmed mechanism by which
radiofrequency energy interacts with biological systems.
He writes she
also said,
a large body of scientific literature demonstrates that
the exposure limits in place protect against adverse thermal effects.
And he reports a
representative of CTIA-The Wireless Association, a trade association,
said in an e-mail that the peer-reviewed scientific evidence has
overwhelmingly indicated that wireless devices, within the limits
established by the FCC, do not pose a public health risk or cause any
adverse health effects. (The Federal Communications Commission, which
also regulates cell phones, declined to comment on the report, Podolosky
writse.)
Editorial says
maybe more brain functions are altered
The authors of an
editorial in the same issue question of these findings may be a marker
of other alterations in brain function from radiofrequency emissions,
such as neurotransmitter and neurochemical activities?
"If so, this
might have effects on other organs, leading to unwanted physiological
responses. Further studies on biomarkers of functional brain changes
from exposure to radiofrequency radiation are definitely warranted,"
write Henry Lai, Ph.D., of the University of Washington, Seattle, and
Lennart Hardell, M.D., Ph.D., of University Hospital, Orebro, Sweden.
They also say,
An important question is whether glucose metabolism in the brain would
be chronically increased from regular use of a wireless phone with
higher radiofrequency energy than those used in the current study.
Potential acute and chronic health effects need to be clarified. Much
has to be done to further investigate and understand these effects."
The study was
carried out at Brookhaven National Laboratory (BNL) and was supported by
the Intramural Research Program of the National Institutes of Health (NIH)
and by infrastructure support from the Department of Energy.
How risky is
cell-phone radiation?
Consumers Report, January 2011
The
Food and Drug Administration says the "weight of scientific evidence has
not linked cell phones with any health problems," including brain tumors
from the low-level radiation that phones emit in normal use, according
to a report in Consumers Report in January.
Yet in the past
year San Francisco lawmakers have enacted an ordinance requiring that
cell phones disclose the amount of radiation emitted, and Rep. Dennis
Kucinich (D-Ohio) announced plans to push for radiation warnings on all
cell phones, according to CR.
Phone
manufacturers are required by federal law to package every cell phone
with information about its specific absorption rate (SAR) values. The
higher the SAR value, the more radiation the body absorbs. But there's
usually no explanation provided with those numbers, not even the fact
that all phones sold have levels lower than what the FDA considers a
concern.
In September
2010, the Federal Communications Commission revised its Web page to
address some of the confusion about SAR values. The updated FCC fact
sheet (www.fcc.gov/cgb/consumerfacts/sar.html)
states that SAR values indicate the maximum possible exposure from a
given phone, not the varying levels of exposure in normal use. So a
phone with a lower reported SAR value isn't necessarily safer than one
with a higher value, and SAR values can't be used to reliably compare
cell-phone models. The FCC says it requires SAR values only to ensure
that maximum radiation exposure falls below the level at which experts
agree there could be adverse health effects.
Still, consumers
are caught in the middle, trying to resolve conflicting messages from
regulators and legislators. (The latter include those in the European
Parliament who have called for stricter limits on exposure to cell-phone
radiation, which have been criticized by many scientists.)
Consumers Union
believes a number of measures would benefit consumers:
● The U.S.
needs a national research program on cell phones and health. Rep.
Kucinich has called for such an effort as part of his cell-phone safety
proposals.
● The FDA and
the FCC should step up their efforts to provide better and more visible
guidance to consumers on the risks, if any, of cell-phone radiation.
● The FCC
should mandate that the SAR information included with phones be more
consistent. The information that's currently provided varies greatly in
its format and detail, as the photographs below illustrate.
>>
Read the complete report and updates in CR
>>
More on Cell phones and services at Consumer Reports
Overview
Ratings
Recommended
Buying Advice
>>
Click to read the complete blog by Consumer Reports editor Podolsky
