No need to panic. A large study in rats claims to show that cellphone radiation may cause cancer, but experts have cast doubt over the findings.
The US National Toxicology Program last week published the of a two-year study, in which more than 1000 rats were exposed to differing levels of cellphone radiation for nine hours every day, for the whole of their lives.
No increases in brain or heart tumours were observed in female rats. But among male rats, around 3 per cent developed a type of brain cancer known as malignant glioma, and up to 6 per cent grew heart tumours called schwannomas.
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Although this hints at a slight increase in cancer risk after prolonged exposure to cellphone radiation, of the US National Institutes of Health, who reviewed the study prior to publication, says the results should be interpreted with caution.
The number of cancer cases was small, meaning they could be statistical blips rather than genuine products of radiation exposure, he says. Moreover, the fact that exposed rats lived longer than control rats, on average, undermines the reliability of the results, he says.
Another peculiarity of the study was that none of the control rats developed cancer.聽Historically, the typical incidence of gliomas and schwannomas in normal rats has been about 2 per cent and 1 per cent, respectively.
of the Open University in the UK is also sceptical. 鈥淚n this experiment, starting before their birth, the animals were subjected to radiofrequency radiation for nine hours a day, seven days a week for their whole lives,鈥� he says. 鈥淢ost people don鈥檛 use their phones anywhere near that much.鈥�
The rats in the study were exposed to a range of radiation intensities, but most of these were higher than those permitted by the current safety limits that are imposed on mobile phone manufacturers.
The higher doses for the rats were well above the safety limits, says McConway. 鈥淚t鈥檚 not obvious to me how these results from high doses in rats can tell us anything yet about normal levels of human mobile phone use,鈥� he says.
For now, the link between mobile phones and cancer remains weak, he says. 鈥淚鈥檓 not going to stop using my mobile phone because of this research.鈥�
Journal reference: bioRxiv,
Read more: Cellphones are 鈥榩ossibly鈥� carcinogenic
