In July 2008, Dr. Ronald Herberman, director of the University
of Pittsburgh Cancer Institute, warned his staff that the risks
from cell phone radiation may be higher than we had thought. He
advised that rather than wait for definitive studies, we should
curb our cell phone use now.
The extensive use of cell phones is a relatively recent phenomenon,
and since cancers usually take at least 10-20 years to develop,
it will be years before research is likely to conclude whether
cell phones cause cancer or not. Meanwhile, there is new research
suggesting behavioral problems in children exposed to cell phones
while their mothers were pregnant or during their early years.
At this point, we don't know as much as we need to know, but there
are several studies suggesting reasons for concern, and other
studies that are more reassuring. This is the first time that
a leading U.S. cancer center has raised concern about cell phone
use, and the first time a medical journal has published a study
indicating behavioral problems in children that may be linked
to cell phones.
What Does Research Tell Us about Cell Phones and Tumors?
A review of 18 studies of cell phones and brain tumors, published
in Occupational Environmental Medicine in 2007 by Hardell and
his colleagues, concluded that studies of individuals using cell
phones for more than 10 years "give a consistent pattern of
an increased risk for acoustic neuroma and glioma" with the
risk being highest for a tumor on the same side of the head that
the phone is used. Gliomas are the most common cancerous brain
tumor and acoustic neuromas are benign tumors of the acoustic
nerve. The studies were conducted in the United States, Sweden,
Finland, the U.K., Germany, and Japan.
So why are companies insisting that the evidence shows that their
cell phones are safe? Cell phone companies tend to focus on the
studies they funded themselves and that draw the conclusions that
will keep their business booming. A good example is a study by
Schuz and colleagues at the Danish Cancer Society and International
Epidemiology Institute, but funded by cell phone companies. This
study included more than 420,000 Danes who first started a cell
phone subscription between 1982 and 1995, and were followed through
2002 to determine if they were diagnosed with acoustic neuroma,
gliomas, or other head cancers. That sounds impressive, but although
the study is described as cell phone users "followed for up to
21 years" the average subscription was started only 8.5 years
before the study was completed, and only 3% had started
using cell phones 15 or more years before the data were analyzed.
Therefore, this study did not evaluate people using cell phones
for a long enough period to determine if they cause cancer. Individuals
with corporate accounts were excluded from the sample, which is
also a shortcoming because they were the early adopters and heaviest
users. This study reported no increased likelihood of brain cancers
for those who used cell phones for more than 10 years; however,
cell phone usage in the 1980s and 1990s was much less frequent
than is common today. Another shortcoming of this study is that
the researchers did not evaluate on which side of the head the
phone was used, which was a key variable predicting tumors in
other studies.
Recent Studies Indicate Higher Risk
A review of the above studies and dozens of others was recently
completed by Vini Khurana, an Australian neurosurgeon. He concluded
that heavy cell phone use can result in a doubling to quadrupling
of the risk of brain tumors in users. His research review is not
funded by cell phone companies and is currently being reviewed
for publication in a scientific journal. Although not yet published,
his report is attracting the attention of many health care providers
and consumers.
Several of these studies were from the Interphone Project, which
is an international effort to investigate possible tumor risks
associated with the use of mobile phones in 13 countries. The
U.S. is not participating in that research. Interphone studies
define "regular cell phone use" as at least one call per week
for at least 6 months, and long-term use is defined as at least
one call each week for at least 6 years. The interphone project
is funded by international organizations (World Health Organization,
European Commission), taxpayer money from participating countries
and by cell phone companies. The project has been underway for
more than ten years and has cost more than $24 million. Results
were supposed to be published in 2003 and 2006 and have been delayed
again due to the need for more research, conflicts over how to
interpret the research, and changes in leadership. However, Sweden,
Denmark, France and Israel have already published their own results.
Dr. Siegal Sadetzki and her colleagues at Tel Aviv University
in Israel have found a link between brain tumors and cell phones.
They reported that heavy cell phone users were more likely to
have benign or malignant tumors of the salivary gland, compared
to those who did not use cell phones."
Bruce Armstrong, who is leading the Australian team in this project,
said that the results are not conclusive yet, but that the emerging
patterns suggest a possible health risk. New studies show higher
risks because studies in the 1990s were conducted too early, before
cancer would have a chance to develop. However, some scientists
are concerned because the frequency of cell phone usage is based
on self-reports, not a more objective measure such as usage reported
on cell phone bills.
Risks for Children
There are no studies of adults who used cell phones extensively
as children and adolescents. Now that many children use cell phones,
such studies are needed to determine whether children might be
more vulnerable to radiation exposure than adults. Researchers
also warn that the effects will be compounded in children and
teenagers as they have started using cell phones earlier than
adults and will continue to use them for longer.
While studies of adults have focused on cancer, a study published
in the medical journal Epidemiology in July 2008 suggests
that cell phone exposure could affect children's behavior. The
children in the study who were hyperactive or had emotional or
behavioral problems, including trouble getting along with other
kids were much more likely to have mothers who used cell phones
during pregnancy. The children's problems, as reported by their
mothers, were even more pronounced for children whose mothers
used cell phones both during pregnancy and during their children's
first seven years of life. The children of these mothers were
80% more likely to have problems than children whose mothers rarely
or didn't use cell phones.
These results, based on a survey of Danish mothers, whose 13,159
children turned 7 in 2005 and 2006, are troubling but also somewhat
difficult to interpret. While the levels of radiation the children
experienced because of their mothers' use were likely very small,
we also know from a study published in the July 7 issue of Physics
in Medicine and Biology, that the brains of children under
8 absorb twice as much radiation from cell phones as do adults.
On the other hand, if mothers using cell phones are paying less
attention to their children, that could also contribute to children's
behavioral problems. Research that provides more details of cell
phone usage and other factors is needed to interpret the relationship
between a mother's cell phone use and her child's behavior, but
meanwhile pregnant women and mothers of young children should
consider limiting their use of cell phones.
Precautions
Scientists recognize that most people are not going to stop using
cell phones. Since these studies suggest their may be risks, Dr.
Khurana and Dr. Herberman recommend precautions that cell phone
users can take.
- Limit the number of calls you make
- Limit the length of your calls
- Use hands free devices or hold the phone away from your body
- When speaking on your cell phone, alternate sides
- Limit your cell phone use in rural areas. More radiation is
emitted when you are further from a cell phone tower.
- Go through these guidelines with your children and limit cell
phone use by young children.
In summary, the published research evidence so far indicates that
using cell phones for several years does not have a clear impact
on brain tumors or cancers. However, a growing number of studies
suggest that tumors may be more common on the side of the head
that is used for phone calls, especially for individuals using
cell phones for more than 10 years.
Most published studies evaluated relatively infrequent cell phone
usage, and that research is inadequate to draw conclusions regarding
safety. The health impact of the frequent, long-term use of cell
phones that is typical today could potentially be substantially
worse and that is why it is important for the Interphone Project
to release their results as soon as possible, and for research
on children to be conducted.
References:
American Friends of Tel Aviv University. "Cell phone-Cancer Link
Found by Tel Aviv University Scientist." 14 Feb. 2008.
July 2008
http://www.eurekalert.org/pub_releases/2008-02/afot-cpl021408.php
Carvajal, Doreen. "Rift Delays Release of Study on Safety of Cell
Phones."
International Herald Tribune. 29 June 2008.
Online Edition.
http://www.iht.com/articles/2008/06/29/business/mobile30.php
Hamilton, Tyler. "Listening to Cell Phone Warnings: Researchers
Working Overtime to Find Out If the Greatest Tool of Business
is Causing Brian Cancer in Those Who Use it Constantly."
Toronto
Star. 31 May 2008. Online edition.
http://www.thestar.com/Business/article/434412
The BBC. "US Cancer Boss in Mobiles Warning."
BBC News
24 July 2008.
http://news.bbc.co.uk/2/hi/health/7523109.stm
