Researchers from University of Sydney examined the association between age and gender-specific 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. With extremely high proportions of the population having used mobile phones across some 20-plus years (from about 9 per cent in 1993 to about 90 per cent today), they found that 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, researchers said. 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. The most likely explanation of the rise in this older age group was improved diagnosis, they said.
Researchers 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. The testing model assumed a ten-year lag period from mobile phone use commencement to evidence of a rise in brain cancer cases.
The model assumed that mobile phones would cause a 50 per cent increase in incidence over the background incidence of brain cancer, researchers said.
The expected number of cases in 2012 (had the phone hypothesis been true) was 1,866 cases, while the number recorded was 1,435, they said.
“Mobile phones produce non-ionising radiation which is low energy, sufficient only to ‘excite’ the electrons enough to make them just heat up,” said Simon Chapman from University of Sydney. The findings were published in the journal Cancer Epidemiology.