Study: Still No Link Between Cell Phones and Brain Tumors
Article date: October 21, 2011
By Eleni Berger
An update of a large study from Denmark finds no link between cell phone use and brain tumors, even with use for 10 years or more. The study is described as the largest to date on this subject; it included all adults over age 30 in Denmark. Even so, there are some questions it could not answer definitively.
The study was done by researchers from the Danish Cancer Society and the International Agency for Research on Cancer. They compared tumor rates in adults who did and did not have cell phone contracts between 1982 and 1995. The researchers have reported on the resulting tumor rates in these groups several times, most recently in 2002. The current analysis is through 2007.
Rates of brain/central nervous system tumors, and of all cancers combined, were essentially the same among people who did and didn’t have cell phones. This held true even for people who had had cell phones for 13 years or longer. It was also true for tumors in the temporal lobe, the part of the brain exposed to the most energy from cell phones.
The results were published in BMJ, the British Medical Journal.
Limitations of the study
Although the researchers were able to compare cancer rates with great accuracy, there were some factors the study could not account for that might have had an effect on the results.
For instance, the researchers could not determine how much any single person might have used a cell phone. People who had cell phone contracts may have used their phones very often and for long calls, or not much at all. And people without a cell phone contract might still have used a cell phone belonging to someone else. The study also could not account for people who had cell phones through their jobs, rather than in their own name. People may also have used their cell phones less, on average, during the years of the study than they are commonly used today.
The study did not include children, either, so the results do not shed any light on the question of whether cell phone use might pose greater risks for them.
Because of these limitations, the researchers note that a small to moderate increased risk in heavy cell phone users or after a longer period of use can't be ruled out completely.
No final word yet
The Danish study is not the only study to investigate the link between cell phones and brain tumors. Last year, the multi-country Interphone study found no definitive link, but also couldn’t rule one out. Most other studies of the issue have also found no link, though a few have.
"The bottom line is that, at this point, there is not strong evidence for an association between cell phone use and cancer in humans,” says Elizabeth Ward, PhD, American Cancer Society national vice president of intramural research.
“However, those who are concerned about this electromagnetic field exposure can reduce it by using earpieces. In addition, it is important for the public to be aware that the primary documented risk of cell phones continues to be their association with vehicle accidents."
Reviewed by: Members of the ACS Medical Content Staff
ACS News Center stories are provided as a source of cancer-related news and are not intended to be used as press releases.
Citation: Use of mobile phones and risk of brain tumors: update of Danish cohort study. Published in the Oct. 20, 2011 BMJ (BMJ 2011; 343:d6387). First author: Patrizia Frei, Danish Cancer Society.
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