Major study finds no link between mobiles and increased cancer risk

The largest and most sophisticated study of the effect of mobile phones on the brain has shown that their use does not increase the risk of cancer.

The largest and most sophisticated study of the effect of mobile phones on the brain has shown that their use does not increase the risk of cancer.

The finding, by the respected US National Cancer Institute, adds to the growing body of evidence that mobile phones are safe, but it does not rule out the possibility that their long-term use may have harmful effects. It also leaves open the question of whether mobile phones have other health effects, such as causing headaches, sleep disturbance and other changes in the brain.

The enormous growth in the users of mobile phones around the world, now estimated to number 500 million, has made establishing any risk associated with the devices urgent. Attention has focused on the low-power, microwave-frequency radiation which they emit. There have been fears that this may cause brain tumours or accelerate the growth of existing tumours.

The researchers collected details of 782 patients with brain tumours admitted to hospitals across the US between 1994, when concerns about the safety of mobile phones first arose, and 1998. They compared mobile phone use among the patients with a control group of 799 people without brain tumours. The results, published in the New England Journal of Medicine, show that people who used mobile phones for 60 or more minutes a day or regularly for five or more years were no more at risk of brain tumours than non-users.

Some mobile phone users did develop brain tumours by chance, as a result of the general incidence of brain tumours in the population. But these did not occur disproportionately on the side of the head on which the phone was typically used.

The finding supports two earlier, smaller studies which also found no link between mobile phone use and brain tumours. An editorial in the journal, by Dimitrios Trichopoulos of the Harvard School of Public Health, Boston, and Hans-Olov Adami, says the results are reassuring.

"Of course we do not have the final word on this question, and the results of future investigations may modify our perspective. Nevertheless we believe that it is highly unlikely that the use of cellular telephones substantially increases the risk of brain tumours."

In Britain, an official inquiry into mobile phones published last May found no evidence of detrimental effects linked with their use.

The Government announced a £7m research programme to try to establish if there are any health effects.