Research published today found no raised risk of brain tumours among those who regularly used mobile phones.
Scientists dismissed evidence from the major international study suggesting a link between extensive mobile phone use and brain cancer.
The findings, pointing to a significant increased risk of tumours for the top 10 per cent of users, were seized upon by groups convinced of the danger from mobile phones.
But leading authors of the 13-nation Interphone study said they were untrustworthy and almost certainly reflected inherent flaws in the research. The general trend indicated that radiation from mobile phones did not trigger brain cancer.
Britain was one of the chief contributors to the Interphone study, which cost £16 million and was largely industry-funded.
Scientists looked at more than 5,000 men and women aged 30 to 59 with glioma and meningioma brain tumours, which affect about one in 10,000 of the UK population per year.
They were compared with around the same number of healthy individuals. Participants were asked for details about their mobile phone usage over the past 15 years, taking into account both the number of calls made and time spent on the phone. Other information was also collected, such as what side of the head people normally held their hand sets.
Cancer rates were analysed to see if they corresponded in any meaningful way to mobile phone use.
In fact, in the research published today in the International Journal of Epidemiology, regular users appeared to have a slightly reduced risk, although this finding was also dismissed as a probable false result by the authors.
There was no sign of a “dose” effect matching an increasingly higher risk with more use, and no association was seen between brain cancer and the number of calls people made.
In their paper, the scientists concluded: “Overall, no increase in risk of glioma or meningioma was observed with use of mobile phones.”
The controversy only arose when the scientists sorted participants into 10 groups according to the accumulated amount of time they had spent talking on mobile phones based on their average usage per day.
In the top 10 per cent of users, the risk of glioma - the most dangerous form of brain cancer - appeared to be raised by 40 per cent and the risk of meningioma by 15 per cent.
However, the study said “biases and error” prevented a “causal interpretation” of these results.
Two senior British authors briefing journalists in London pointed out that some of those in the top 10 per cent bracket reported “improbable” use levels of 12 hours or more every day.
Tests designed to uncover study flaws suggested that brain cancer patients were likely to exaggerate when asked questions about mobile phone use. Psychological bias may have affected their answers and brain tumours were known to affect thinking and memory, said the scientists.
Campaigners Mast Sanity called the Interphone findings a “whitewash” and evidence of an industry and government “cover-up”. The charity pointed out that the results were five years overdue with reports of “deep divides” between researchers.
It called on study co-ordinators the World Health Organisation and the International Agency for Research on Cancer to “come clean and admit that mobile phone use does cause brain cancer”.
Dr Grahame Blackwell, from the group WiredChild, said: “The results of the Interphone study raise serious concerns about likely effects on children - their biological vulnerability and lifetime use mean they are very exposed.”
Since Interphone was launched, children’s use of mobile phones had soared, said the charity. At the same time, childhood rates of brain cancer had been increasing.
PA