April 11, 2005 -- Cell phones don't cause brain tumors, as far as scientists can tell at this point, says a study in Neurology's April 12 edition.
The findings echo previous research. "These results are in line withon this question," says Christoffer Johansen, MD, PhD, DMSc, in a news release.
"There have been a few studies that found an increased risk of brain tumors with cell phone use, but those studies have been criticized for problems with the study design," says Johansen, who works at the Danish Cancer Society in Copenhagen.
Long-term effects of cell phone use aren't known yet, Johansen cautions. Hardly anyone in his study had used a cell phone for more than a decade.
Participants were 427 Danish brain cancer patients and 822 randomly selected Danes without brain tumors.
The researchers had access to almost all recorded brain cancer cases in Denmark. All brain tumor patients were adults diagnosed from 2000-2002.
The researchers were able to obtain the number of incoming and outgoing calls among two small groups -- 27 brain tumor patients and 47 without brain cancer. No association was seen between cell phone use and brain tumors.
In the brain cancer patients, the tumors didn't favor the side of the head where people usually held their cell phones.
Other countries are also participating in the project. Their findings aren't in yet.
It's easy to lose track of how long you've chatted or how many calls you make or take. That's why the researchers compared the participants' reported cell phone use with cell phone company records.
Everyone accurately remembered how many calls they made. However, both groups were a little fuzzier about how long they'd chatted.
"In our study, few people reported regular cell phone use for 10 years or more," says Johansen in the news release. "We won't be able to make any firm conclusions until we can confirm these results with studies with more long-term and heavy cell phone users."
Precautions for Kids, Adults, Drivers
Johansen's study doesn't advise people one way or the other on cell phone use. In January, the British Radiological Protection Board advised a until potential risks are better understood. That goes for kids, as well as adults, the board said.
As for driving and dialing, that's illegal in some areas. It's also distracting, even with hands-free phones, say experts, calling the problem "inattention blindness."
In a driving simulation study, drivers using handheld or hands-free cell phones missed more traffic signals and reacted slower to signals than those not on the phone, researchers reported in the March 2003 edition of the Journal of Experimental Psychology: Applied.