The Danish study questioned 427 people with brain tumors and 822 people without brain tumors about their cell phone use. The study found no increased risk for brain tumors related to cell phone use, frequency of use, or number of years of use.
"These results are in line with other large studies on this question, including a recently published large-scale, population-based study by the Swedish Interphone Study Group," said study author Christoffer Johansen, PhD, DMSc, MD, of the Danish Cancer Society in Copenhagen. "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."
For 27 people with brain tumors and 47 people without brain tumors, researchers obtained phone records from cell phone companies to document the amount and length of calls and compare the actual calls to what participants reported. Those results found that people accurately remembered the number of calls they made, but did not accurately remember the length of those calls. But there were no differences between the two groups on how well they portrayed their cell phone use. Johansen said that finding minimizes the possibility of what researchers call "recall bias," or the chance that people with brain tumor may exaggerate or underestimate their past cell phone use.
Johansen noted that there have been few long-term cell phone users or heavy cell phone users in any of the studies. "In our study, few people reported regular cell phone use for 10 years or more," he said. "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."
The researchers also found that brain tumors did not occur more frequently on the side of the head where the phone was typically used.
The study was supported by the European Commission Fifth Framework Program, International Union Against Cancer, International Epidemiology Institute, and Danish Cancer Society.
The American Academy of Neurology, an association of more than 18,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as Parkinson's disease, dementia, ALS, narcolepsy, and ataxia.
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