A MAJOR international study has found a link between mobile phone use and certain brain tumours.
Now leading scientists have called for restrictions on children's access to mobiles and stricter government advice to adults on their use.
The 15 million Interphone study, due to be published on Tuesday, was backed by the World Health Organisation and took ten years to produce.
It is set to show "a significantly increased risk" of some brain tumours "related to use for a period of ten years or more" of mobile phones.
However, some scientists have raised doubts over the study's methods.
Study links brain cancer to mobile phones
PARENTS have been warned to restrict their children's mobile phone use after a global study found a link between the most common brain cancer and prolonged use of the devices.
The results of the Interphone study, to be officially released on Tuesday, will include some evidence that those who regularly hold long conversations on handsets are at increased risk of developing potentially fatal tumours.
However, the study is set to spark controversy amid claims that research methods used could have skewed the results.
Despite the row, the findings are expected to prompt the government to update its health advice on mobile phones use, which has remained unchanged for four years.
Usage among children has increased dramatically in the past decade but current advice only says use should be "discouraged" in the very young.
The World Health Organisation commissioned the research, which took 10 years and examined the habits of 12,800 phone users.
According to reports, the study concludes prolonged mobile phone use over a 10-year period created a "significantly increased risk" of a type of brain tumour called glioma, prompting the call for restrictions on use among the young.
Dr Siegal Sadetzki, one of the 13-nation team of researchers, said: "Most studies, including ours, show something happening in long-term users. Why shouldn't we take some simple measures to limit exposure just to be on the safe side?"
Dr Elisabeth Cardis, who headed the Interphone research project, added: "I am in agreement with restricting use by children, though I would not go as far as banning mobiles."
The results have been seized on by campaigners who claim a link between mobile phones and cancers. Professor Denis Henshaw, head of the Human Radiation Effects Group at Bristol University, has been a long-term critic of allowing children unrestricted mobile phone use. He said: "Why should it come as a surprise that pressing mobile phones to people's ears increases the risk of brain tumours? These findings are completely as expected from other evidence.
"Children are known to be more vulnerable and we need to take action to protect them. The challenge now is how we respond. Burying our heads in the sand is asking for trouble."
The project includes some studies that appear to show a rise in the risk of brain tumours linked to mobiles. Israeli studies included found heavy users were at least 50 per cent more likely to suffer tumours.
Two more studies reported a higher risk after using mobiles for 10 years. A Swedish report said it was 3.9 times higher.
A summary of the results stated: "Pooling of data from Nordic countries and part of the UK yielded a significantly increased risk of glioma related to use of mobile phones for a period of 10 years or more on the side of the head where the tumour developed."
But the scientists who contributed to the decade-long, 15 million project are likely to face criticism that, despite the time and expense involved in their work, the data obtained is inconclusive and susceptible to error.
At the start of the project, it was known that radio-frequency radiation emitted by mobiles is absorbed by the body, much of it by the head when the handset is held to the ear. But research into whether frequent mobile phone use damages health had proved inconclusive, mainly because the technology is relatively recent.
Between 2000 and 2004, researchers therefore interviewed tumour sufferers and those in good health – 12,800 in total – to see if their mobile phone use differed.
Some of the studies that have been published individually showed increased risk of glioma – the most common type of brain tumour – among those who talked on a mobile for about 30 minutes a day for 10 years. Many who developed the tumours saw them grow on the same side of the head as they held their handsets.
Interphone will hold back from asserting that mobile phones cause cancer as it ruled the evidence was not conclusive and also because of questions over its reliability.
Its definition of "mobile phone user" included people who only made one call a week, and many fear that accurate results cannot be obtained by asking people to recall how often they used their mobile phones, and to which ear they held them, several years prior to being surveyed.
It has been claimed the positive results could be explained by "recall bias" as people who have developed brain tumours are likely to believe they must have been caused by something, such as their previous use of mobile phones.
The final results of the study, a quarter of which was funded by the mobile phone industry, has been delayed for four years while the authors argued over how to present the conclusions but will be published in a scientific journal this week.
It will call for more research, particularly among the young, and also warn that more frequent use among the world's four billion mobile phone owners means that exposure to radiation is now far higher than the data used in Interphone.
Despite its limitations, Interphone remains the largest study carried out into the safety of mobile phones, so health ministries worldwide and the billion-pound telecommunications industry are likely to rely heavily on its findings.
The Department of Health has not updated its guidance for more than four years and only suggests children should be "discouraged" from making "non-essential" calls while adults should "keep calls short". Many countries are already moving to restrict mobile use among the young.
Tougher rules abroad
In the UK there are no restrictions at all on mobile phone use among children.
The UK department of health advises that calls should be kept short but there are no legal barriers to children talking for hours if they wish.
In France operators must offer parents text message only models so that children can keep in touch without putting the phones to their ears.
In Germany low emission phones which have special blue angel mark on them must be made available to children.
In Australia children are advised to use mobiles only in emergencies.
In Israel the government have gone further, officially discouraging the use of mobiles in public places or on trains and buses due to fears over health risks. However, other countries have urged users to buy hands-free sets or send texts rather than making calls, or to ban advertising of phones aimed at children.