Do mobile phones cause brain tumours?
Mobile and cordless phones emit a form of microwave energy known as radiofrequency electromagnetic fields (REF). The media is full of alarming news stories about possible links between mobile phones and cancer. This is a controversial subject and, despite various scientific studies, the results have been contradictory making it a difficult to draw a definite conclusion.
Our Director of Research, Kieran Breen, provides this up-to-date report on this situation.
What is the current evidence?
A recent research paper published in Australia examined a potential relationship between mobile phones and cancer. The researchers there concluded that a general increase in brain tumours which has been observed over the last 20 years can probably be attributed to improved diagnostic techniques and is unlikely to be associated with an increase in mobile phone use.
A group in Sweden suggest that some of the cancer registries that have been used previously may be unreliable and that they have failed to detect all cases of brain tumours, so the effect of REF cannot be ruled out.
We don’t know how the phones might stimulate tumour development. Although we know that these devices emit REF, this has millions of times less energy than, say, an X-ray and therefore unlikely to be powerful enough to damage our DNA to make cells cancerous.
But we can’t discount the fact that there may be other ways by which REF could be having an effect. A recent study in America suggested a found link between REF and the incidence of brain tumours in rats. However, the tests are not complete and the relevance to the human situation is questionable.
How can we study the potential of REF in the generation of brain tumours?
The key challenge to assess any causal relationship between REF and brain tumours is to analyse all the previous studies together with ongoing research in order to capture the most comprehensive data available.
We know that there is a great variation between the time between brain tumour type, initiation and the development of symptoms. In some cases, a brain tumour may remain dormant for a number of years before symptoms appear. In some cases, brain tumours can be clinically ‘silent’ and discovered by accident.
If we can’t tell accurately when the tumour initially developed, it is extremely difficult try to identify specific causes. Population studies have been carried out, looking for trends in disease incidence and general lifestyle changes but again the results that have been obtained from a number of these studies are inconsistent and are very much determined by the data that is available and how it is analysed.
What is the current official position?
The International Agency for Research into Cancer, which is part of the World Health Organisation (WHO), convened a panel of experts in 2011 to examine the evidence that was available at the time. They concluded that REF should be classified as a Group 2B carcinogen, which means that it “possibly” causes cancer in humans. This is the same category as lead, engine exhaust, DDT, and jet fuel. Once again, while there may be an association, the available evidence did not allow for a definitive conclusion to be drawn.
Other experts suggest that REF should be reclassified as Group 2A (“probable” human carcinogen).
The WHO is currently conducting a formal risk assessment of all studied health outcomes from radiofrequency fields exposure and a report is due to be published later in 2016. We will update you here on our blog once this report in published.
What is the official advice?
The UK Department of Health has published a leaflet which recommends that anyone under the age of 16 should only use mobile phones for short essential calls, as children have been found to absorb 60% more radiation into their heads than adults when they use a mobile phone. Official user manuals warn customers to keep the mobile phone away from the body when turned on and not to hold it right up to the head when using the device.
Official Brain Tumour Research recommendation is that mobile and cordless phones and should be used sparingly, and remote speakers or ear buds with built-in microphones should be used whenever possible.