Mobile phones: where did the story go?

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This Friday's xkcd comic was about mobile phones and cancer. Regular readers of UU will know that I've shown an interest in that subject before, here, here and here. The main point of the comic was good, but what's this "another huge study" on phones and cancer in the first frame of the comic, and why hadn't I heard about it?

The answer doesn't tell us much about phones and cancer, but it does tell us quite a bit about how stories about health get into the press.

The new study referred to seems to be another one investigating whether there is a link between heavy mobile phone use and a rare non-malignant brain tumour called acoustic neuroma or vestibular schwannoma. It's a large-scale observational study carried out in Denmark, involving looking at the records of mobile phone subscription and of diagnoses of these tumours in very large cohorts of people (nearly 3 million of them). Even in this huge group, there were only 805 cases of the disease in question, pointing up the difficulty of investigating the causes of rare diseases. The study found no evidence of an increased risk of acoustic neuroma in long-term mobile phone subscribers, compared to short-term subscribers and nonsubscribers. It's available on the website of the journal that published it, the American Journal of Epidemiology, though there's a paywall for the full article.

We wouldn't want to claim that any single study, taken on its own, establishes what does or doesn't cause a disease, particularly one like this where the disease is rare and there are serious and largely unavoidable methodological problems in digging out causal links. But any pronoucement on mobile phones and brain tumours is usually reported in the UK press. Why hadn't I spotted this one?

Actually the study was reported quite heavily in the press in the US and several other countries, in the last few days, and it seems to have been this reporting that sparked the xkcd comic. These press reports seem to have stemmed from a report put out by the Reuters press agency that appeared last Thursday, 14 July.

But some fairly assiduous Web searching failed to come up with any reports of the study in the UK, apart from one or two on UK websites. Certainly nothing (yet) in the press or mainstream media. The story seems simply not to have fitted into the current news agenda, alongside all the fuss being made about the closure of the News of the World and the activities of News International and the Murdochs. (Readers from outside the UK might be unaware of the huge extent to which these have dominated the media here recently.)

There's a further question. The Reuters report came out on 14 July, but the actual journal article was published on the American Journal of Epidemiology website as long ago as 28 June. But I've failed to find any report of the study, anywhere in the world (in the English language at least), before the Reuters report. Why did it take over two weeks to make its mark?

As far as I can see, that's because there was no press release on ths study by the journal or the study authors. It's not routine for such press releases to be issued - they are if the author, or their institution, or the journal, wants to try to make a particular splash. I don't know why that didn't happen in this case (or maybe it did, and I've simply failed to find the press release - if you know there was one, please comment!). Reuters eventually picked it up anyway, and so it did get onto the news agenda in the US, but not here because something else was in the way.

The moral of this story has nothing at all to do with mobile phones or cancer. It is that you can't get a full story of what's going on on a health issue by simply following what's in the mainstream media. What you'll find there is not necessarily what you want to read, but what other people want you to read.

Be careful out there!



Maybe they did know about it, but there's not much news value in "no evidence that mobile phones cause cancer" to those who got a lot of milage out of the original scare story, so they just chose to ignore it. Publication bias in mass media is even worse than in academic journals.

You could well be right. On the other hand, the review led by the Institute of Cancer Research that came out at the start of July, which concluded "Although there remains some uncertainty, the trend in the accumulating evidence is increasingly against the hypothesis that mobile phone use can cause brain tumours in adults", got pretty heavy press coverage.

Latest Interphone release 25 Aug. 2011 - - 'Heavy Use - higher risk' Read further - Joachim Schuz (Danish Study) and the ICNIRP ' Friends of Industry No riskers'.