Mobile phones hit headlines this morning because a press release linked an increase in brain tumour cases in England with the devices.
But this bold claim isn't backed up by the results of the study the press release was promoting to journalists, published in the Journal of Environmental and Public Health.
What did the study do?
Researchers looked at the number of people with brain tumours in England, and calculated how this figure changed over time.
They used figures from the UK Office of National Statistics (ONS) from 1995 to 2015.
Using this database, they looked for changes in the diagnosis of specific types of brain tumours, and where these tumours grow in the brain.
What did the study show?
They found that cases of an aggressive type of brain tumour called glioblastoma multiforme, found in the forehead and side regions of the brain, had risen sharply in recent years in England.
Cases of other types of brain tumour had remained consistent or fallen since 1995.
What do the results mean?
The researchers showed that there has been a rise in people diagnosed with this specific type of brain tumour in England.
What they didn't find is a cause for this increase. They couldn't, because the study wasn't set up to answer this question.
There are lots of factors that could explain the increase in this type of brain tumour, including improvements in diagnosis and changes in the way brain tumours are classified. But it's impossible to know for sure without more information and studies designed to find these answers. Until then, all we have are (hopefully) educated guesses.
That's where mobile phones came in.
Mobile use was discussed in the paper as one of the factors that could explain the increase. But the press release took it a step further, singling out excessive mobile phone use as a 'likely cause'.
As scientists speaking to Science Media Centre explain, this is not backed up by the study itself. "This paper does not attempt to link the rise in mobile phone use with a rise in brain tumour incidence directly," says Dr. Lion Shahab, a senior lecturer in epidemiology and public health at University College London.
And Professor Malcolm Sperrin, director of the Department of Medical Physics and Clinical Engineering at Oxford University Hospitals NHS Trust, warned people to "not stretch the data too far" as there are other factors that could explain the results.
The big picture
As it stands, there isn't any conclusive evidence that links mobile phone use to brain tumours. But there also isn't enough evidence to say that absolutely no risk exists.
We've summed up the most important findings before, and the take-home message is that while using a mobile phone is unlikely to cause cancer, scientists need more long-term data to be sure.
But one thing is clear: despite the headlines, the latest study doesn't add all that much to the mobile phone debate.
Explore further: A better understanding of brain tumour biology will bring new treatments
Brain tumours: rise in Glioblastoma Multiforme incidence in England 1995–2015 suggests an adverse environmental or lifestyle factor. Journal of Environmental and Public Health www.hindawi.com/journals/jeph/aip/7910754/