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Mobile phone cancer link unproven, says HPA

Thursday 26 April 2012

There is “no convincing evidence” that mobile phones cause cancer, according to a major report issued by the Health Protection Agency. The report has received a great deal of press attention. Most newspapers stressed the lack of clear risks but others said that mobile phones present an unknown health risk.

The report was a comprehensive, independent review of the evidence on the possible health effects of exposure to radiofrequency (RF) electromagnetic fields. RF fields are produced not only by mobile phones, but also by other wireless devices such as Wi-Fi, TV and radio transmitters. After looking at hundreds of evidence sources, the review concluded that there is still no convincing evidence that exposure to RF below international guidelines causes any damage to health in adults or children.

However, the review pointed out that mobile phones, which produce the highest exposures to RF in daily life, have only been in widespread public use relatively recently and there is little information on any health risks beyond 15 years of use. On this basis, the researchers say that more information is needed on whether there is an increased risk of brain tumours and other types of cancer with longer-term mobile use and use during childhood. In particular, the authors say a study should be undertaken to look at trends in the rates of brain tumours in the UK population by age and sex in relation to trends in mobile phone use. The overall message is that to date there is no evidence to support a risk, but that as a precautionary measure monitoring should continue.

The current advice from the Department of Health is that children and young people under 16 should be encouraged to use mobile phones for essential purposes only, and should keep any calls short. Using a hands-free kit and texting instead of calling are both ways to reduce RF exposure.

What did the report look at?

The report presented findings from an extensive evidence review by the Health Protection Agency’s independent Advisory Group on Non-ionising Radiation (AGNIR). AGNIR published its previous review of the subject in 2003, and this analysis addressed a great deal of evidence gathered in the intervening years.

The report looked at evidence on the possible health effects of exposure to certain radiofrequency (RF) electromagnetic fields, produced by a range of man-made devices. The report pointed out that the general public is exposed to RF fields from mobile phones and their base stations, wireless networking, TV and radio broadcasting and other communications technologies. Although such exposure has become widespread, it still remains below internationally accepted guidelines on safety.   Additional sources of RF exposure are appearing from new technologies such as domestic smart meters and airport security scanners, while some members of the public and the workforce are exposed to higher levels used in MRI scanning and intense heat-based medical therapies. In particular, it says there have been concerns about the use of Wi-Fi in schools.

The type of low-level radiation emitted by mobile phones, radio signals and Wi-Fi is called non-ionising radiation. This is different from the ionising radiation (the type that breaks down molecules and structures within cells) that is emitted by radioactive materials, X-rays and medical techniques such as radiotherapy, for example. Non-ionising radiation is naturally present at very low levels in the environment.

The potential effects of RF fields have been studied in a variety of ways and settings. The review examined many different kinds of studies, from studies that looked at cells in a lab to those that examined how RF fields affect people in the long-term. The broad types of studies examined were:

  • studies at the cellular level
  • studies in animals
  • studies of brain function in humans
  • studies of symptoms in humans
  • studies of non-cancerous effects in humans
  • studies of cancer in humans

What research did it consult?

The review looked at hundreds of studies related to the potential health effects of exposure to RF fields. It concentrated particularly on new evidence gathered since 2003, the date of the last review. The report covered both experimental and population-based studies relevant to concerns about human health. However, the studies only looked at the direct effects of exposure to RF fields and did not cover indirect effects associated with the use of mobile phones and other wireless devices, such as the accident risks of using mobile phones while driving.

Its authors did not describe their search in detail, but said that all scientific papers were carefully examined to determine what weight should be placed on their individual findings, including consideration of their scientific quality.

What did the report find?

Below are the main findings of the report for the different types of studies it reviewed.

Studies on cells

The report says there is no robust evidence that RF exposure produces any effect on cells. In particular, there is no evidence that RF fields cause genetic damage or increase the risk of cells becoming cancerous at the levels tested.

Animal studies

The report says that, taken together, these studies provide no evidence that RF exposures below international guidelines have health effects. Large-scale animal studies have found no evidence that RF fields are associated with cancer and no consistent evidence of effects on the brain, nervous system, blood-brain barrier or on fertility.

Brain function in humans

Some studies have suggested that RF fields might affect brain function, but further research is required. The report says that at present there is insufficient good-quality evidence to draw strong conclusions about the potential effects of RF exposure on brain function in children.

Symptoms in humans

The authors say current evidence suggests that RF exposure below guideline levels does not cause acute symptoms in humans. They also say that at present there is insufficient evidence to draw conclusions about the role of long-term exposure in causing symptoms.

Non-cancer effects in humans

The authors consider research in this area to be “limited”, but say that to date there is no substantial evidence that exposure has effects on cardiovascular health, fertility or death rates. There is in particular “a lack of evidence available in children in this area”.

Cancer in humans

The authors say studies do not indicate that there is a cancer risk form RF field exposure – for example, from living near an RF transmitter – but these studies have weakness and provide no strong evidence against a possible increased risk.

They say that to date, the overall evidence does not demonstrate that use of mobile phones causes brain tumours or any other type of cancer. However, they add that there is little information about the risks beyond 15 years of use and very limited information on the risks of childhood tumours associated with mobile phones.

What did the report conclude?

In summary, the report said there is “no convincing evidence that RF exposure below agreed international guideline levels (which the UK adheres to) causes health effects in adults or children”.

Does that mean mobiles are safe?

The report suggests that to date there is no clear evidence that RF exposure might cause cancer. This is different from finding evidence that it does not cause cancer. The report calls for research to continue monitoring the effects of mobile phones. In particular, little is known about their longer-term effects and potential effects on children. A study should be undertaken to look at trends in the rates of brain tumours in the UK population by age and sex in relation to trends in mobile phone use.

What are the recommendations on phone use?

The Department of Health currently advises that children and young people under 16 should be encouraged to use mobile phones for essential purposes only and should keep calls short. Using a hands-free kit and texting instead of calling are both ways to reduce RF exposure.

Analysis by Bazian
Edited by NHS Website