Confusion over mobile phone cancer risk

A huge ten year study into possible links between mobile phone use and cancer, covering 13 counties and costing £15m, has failed to provide a definitive answer.

Although there is some suggestion that extreme mobile phone usage over many years may contribute to an increased risk of developing some rare forms of cancer, even this "fact" may be incorrect due to possible flaws in the way the data was collected and analysed.

About the study

The Interphone study was coordinated by the International Agency for Research on Cancer (IARC), part of the World Health Organization (WHO). Around a quarter of the costs of the study were funded by mobile phone trade associations, with controls put in place to prevent interference in the results.

It focused on cases of four types of tumours found in parts of head that most absorb the radiation produced by mobile phones.

Between 2004 and 2008 over 12,000 people were interviewed about their mobile phone habits. The study included more than 5,000 people who had been diagnosed with one of two types of brain cancer - glioma and meningioma. It should be pointed out that both these cancers are rare.

The results

In general the study could see no link between normal phone use and cancer rates. In fact there has been no general rise in brain cancer rates during the period in which mobile phones have become widespread, and no recorded increase in countries with the highest usage rates.

This ties with the fact that there is (as yet) no known mechanism by which mobile phones can cause cancer.

Surprisingly the study found that moderate mobile users had a lower risk of brain tumours that those who use them rarely.

But the study did find that for those people who had used mobiles frequently for more than 10 years there was an increased risk of some brain cancers.

Issues with the study

The main issue with the study is that it was based on the participants own memories of their phone use over the last 10 years. Some of the numbers provided at the extreme end are barely credible (with some claiming to use their mobile for 12 hours a day!).

Also the calculation of the risks is based on the reported behaviour of the participants who had been diagnosed with brain cancer, and there is evidence that people are prone to over exaggerate risk factors in this situation.

Other factors

Modern mobile phones produce less radiation emissions that those in use at the time of the study. However more people are now using phone for longer, and from an earlier age. The inconclusive nature of the study means that more work needs to be done.

However the main result is that so far there is no link between sensible mobile use and brain cancer rates.

The study is published in the International Journal of Epidemiology.

This article was published on Tue 18 May 2010