French scientists are reporting people who use mobile phones intensively appear to have a higher risk of developing certain types of brain cancer in new research that revives questions about phone safety.
The findings, Medical Xpress reports, are based on a new study showing individuals who used a cellphone for more than 15 hours each month over five years on average had between two and three times greater risk of developing glioma and meningioma tumors compared with those rarely used such devices.
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The study, published in the British journal Occupational and Environmental Medicine, is the latest in a long-running series of studies of mobile-phone safety – most of which have found there is little scientific evidence they pose a major public health threat.
Over the last 15 years, most research has failed to turn up conclusive evidence of a risk, but several have suggested a link between gliomas and intensive, long-term use.
"Our study is part of that trend, but the results have to be confirmed," said Isabelle Baldi, of the University of Bordeaux in southwestern France.
In 2011, the International Agency for Research on Cancer (IARC) said radiofrequency fields used by mobile phones are possibly carcinogenic, but said more research is needed.
The new study looked at 253 cases of glioma and 194 cases of meningioma reported in four French counties between 2004 and 2006. These patients were compared to 892 healthy individuals drawn from the general population.
The comparison found a higher risk among those who used their phone intensively, especially among those who used it for their work. But study also found several inconsistencies with other investigations that have suggested a link between heavy phone use and brain cancer.
For instance, it found that cancer occurred on the opposite side of the brain, rather than on the same side, of where the phone was customarily used.
"It is difficult to define a level of risk, if any, especially as mobile phone technology is constantly evolving," the study acknowledged.
"The rapid evolution of technology has led to a considerable increase in the use of mobile phones and a parallel decrease of [radiowave intensity] emitted by the phones. Studies taking account of these recent developments and allowing the observation of potential long-term effects will be needed."
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