There is no link between mobile phones and brain cancer, a landmark study has revealed.
Researchers found no increase in tumours over the last 29 years, despite an enormous increase in the use of the devices.
In Australia, where the study was conducted, 9 per cent of people had a mobile phone in 1993 - a number which has shot up to 90 per cent today.
But in the same period, cancer rates in people aged 20 - 84 rose only slightly in men and remained stable in women.
There were ’significant’ rises in tumours in the elderly, but the increase began five years before mobile phones arrived in Australia in 1987, the researchers said.
The study’s author, Professor Simon Chapman, of the University of Sydney, said phones emit non-ionising radiation that is not currently thought to damage DNA - and his findings make him even more confident the devices are not li[n]ked to cancer.
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We examined the link between age and incidence rates of 19,858 men and 14,222 women diagnosed with brain cancer in Australia between 1982-2012, and national mobile phone usage data from 1987-2012.
Extremely high proportions of the population have used mobile phones across some 20-plus years -from about 9 per cent in 1993 to about 90 per cent today.
We found age-adjusted brain cancer incidence rates (in those aged 20-84 years, per 100,000 people) had risen only slightly in males but were stable over 30 years in females.
There were significant increases in brain cancer incidence only in those aged 70 years or more.
But the increase in incidence in this age group began from 1982, before the introduction of mobile phones in 1987 and so could not be explained by it.
Here, the most likely explanation of the rise in this older age group was improved diagnosis.
Computed tomography (CT), magnetic resonance imaging (MRI) and related techniques, were introduced in Australia in the late 1970s.
They are able to discern brain tumours which could have otherwise remained undiagnosed without this equipment.
It has long been recognised that brain tumours mimic several seemingly unrelated symptoms in the elderly - including stroke and dementia - and so it is likely that their diagnosis had been previously overlooked.
Next, we also compared the actual incidence of brain cancer over this time with the numbers of new cases of brain cancer that would be expected if the ’mobile phones cause brain cancer’ hypothesis was true.
Here, our testing model assumed a ten-year lag period from the start of mobile phone usage to evidence of a rise in brain cancer cases.
Our model assumed that mobile phones would cause a 50 per cent increase in incidence of brain cancer.
This was a conservative estimate that we took from a study by Lennart Hardell and colleagues (who reported even higher rates from two studies).
The expected number of cases in 2012 (had the phone hypothesis been true) was 1,866 cases, while the number recorded was 1,435.
