A new study of 358,403 mobile phone subscribers over an 18 year period suggests that there may be no link between phone use and the prevalence of brain tumours, although Australian experts are cautious about the results. It's one of those topics that seems to be endlessly debated. First they're safe. Then they're not. A study of 358,403 users should settle matters, right? Not so fast; proper science doesn't quite work like that; it's still a matter for hypothesis, testing, peer review and further research.
The study results, published in BMJ do appear encouraging, but it's only a partial study. According to Rodney Croft, Executive Director of the Australian Centre for Radio Frequency Bioeffects Research and Professor of Health Psychology in the School of Psychology at the University of Wollongong,
This Danish study looked to see whether there was a relation between mobile phone use and brain tumours, across a very large number of people (358,403), and across a large time frame (up to 18 years). Consistent with previous research, it failed to find any relation between brain tumours and mobile phone use. This is important because it has been argued that previous research was limited in that it had not looked at people who had used mobile phones for longer than 10 years, which this study was able to do.
However, as acknowledged in the paper, this research design has limitations that make it difficult to be certain of the results (such as the reliance on mobile phone subscription data as a surrogate for mobile phone use), but its conclusions certainly support the view that mobile phone use does not cause cancer."
It's a view shared by Bruce Armstrong, Professor of Public Health at the University of Sydney’s School of Public Health.
There are two things that must be borne in mind with this study. The first is that this is a study of mobile phone subscribers, not mobile phone use. Thus risk cannot be related to actual amount of use, only to length of subscription. The second thing is that it is not true to say that the study shows no association between mobile phone subscription and risk of brain tumours. There was weak evidence of an association between mobile phone use and risk of brain tumours, but any evidence of increased risk was not more evident in the temporal lobe (temporal glioma), which is the area that is most exposed to mobile phone radiation and where you would expect to find evidence of an association, nor in people who had held subscriptions for the longest time.
The bottom line is that the study does not change my overall view that there is still considerable uncertainty remaining about the risk of mobile phone use and brain tumours. While the evidence is weak, it is possible that mobile phone use does cause brain tumours and we need further research."
So, in other words, the research continues, but you appear to be more safe. For now. [BMJ]