Whether cellphones cause brain cancer has been a subject of ongoing debate, but a new study confirms previous evidence suggesting that they don't.
A 30-year examination of the incidents of brain tumours in Scandinavia found no substantial change in prevalence even after cell phone use became widespread, according to the report in the Journal of the National Cancer Institute.
"If mobile phones were to cause brain tumours we would expect to see a sudden rise in the number of brain tumours at some point in time, and we don't see it," said lead researcher Isabelle Deltour, from the Institute of Cancer Epidemiology at the Danish Cancer Society in Copenhagen.
However, Deltour leaves the door open to the possibility that widespread cell phone use hasn't been around long enough to see an increase in brain tumours.
"Either it means that mobile phones don't cause brain tumours or it means that we don't see it yet or we don't see it because the increase is too small to be observed in this population, or it is a risk that is limited to a small subgroup of the population," she said.
Deltour's team will continue to look at the rates of brain tumours in the study group, she added.
For the study, Deltour's team collected data on 60,000 people diagnosed with glioma and meningioma in Denmark, Finland, Norway and Sweden between 1974 and 2003.
The researchers found that the incidence of brain tumours over this 30-year period were stable, decreased or gradually increased, starting before cellphones became popular.
In addition, there was no change in the incidence of brain tumours between 1998 and 2003, during a period of rapid increase in cell phone usage, the researchers noted.
Dr Paul Graham Fisher, an associate professor of neurology, paediatrics, and neurosurgery and human biology and the Beirne Family Director of Neuro-Oncology at Stanford University, said that "this topic won't go away."
Fisher thinks that like so many irrational fears, such as harm from radiation from electric wires, the connection between cell phones and brain tumours will persist even though there is no scientific evidence for such a connection.
"This is sort of the high-tension wires of our time," Fisher said. "This is an issue that is probably not going to go away, because people have this suspicion and it's fuelled by some public paranoia and by people who make very provocative statements, and that is enough to make it not go away, despite very good science."
However, a review of existing research on the topic, published in the Journal of Clinical Oncology, did find a slight, potentially harmful association between cell phone use and brain tumours.
Commenting on that study, Dr Deepa Subramaniam, director of the Brain Tumour Centre at Georgetown Lombardi Comprehensive Cancer Centre in Washington, DC, said at the time that "we cannot make any definitive conclusions about this. But this study, in addition to all the previous studies, continues to leave lingering doubt as to the potential for increased risk. So, one more time, after all these years, we don't have a clear-cut answer." - (Steven Reinberg/HealthDay News, December 2009)