London:  People who begin using mobile phones as teenagers and continue to do so for over a decade may be at a fivefold risk of developing a common type of brain cancer, Swedish scientists have claimed, citing new evidence.

The study, published in the International Journal of Oncology, found large increased incidence of astrocytoma, the most common form of a malignant brain tumour type called glioma, in those who had been using mobiles for over 10 years.

The new research comes weeks after the International Agency for Research on Cancer, which is part of the World Health Organization, stated that radiation from handsets was "possibly carcinogenic", though it stopped short of declaring there was a clear link.

Campaigners, meanwhile, said the research was further evidence of the need to educate children of the potential dangers of mobile phone usage, reported a newspaper.

For the study, the researchers from the University Hospital of Orebro and Umea University examined the mobile and cordless phone use of more than 1,200 Swedes, who were diagnosed with malignant brain cancer between 1997 and 2003.

Of those, the 905 who were still alive were interviewed about their phone usage. For the remaining 346, who had died, researchers asked their relatives about their loved-ones' telephone habits.

Then they compared this to phone use information on almost 2,500 "controls" that were either living and had no brain cancer, or had died of other causes.

After matching each "case" and each "control" for age, sex and social class, the team concluded that using both mobiles and cordless phones led to "an increased risk for malignant brain tumours".

People who started using mobiles as teenagers, and have done so for at least 10 years, were 4.9 times more likely to develop astrocytoma as compared to controls, the researchers added. Worryingly, the researchers said the comparative figure for cordless home phones -- which are very similar to mobiles in terms of radiation emission - was almost as high, at 3.9.

Looking at the whole group, regardless of age of first rise of mobile or cordless phone, they found that usage for more than 10 years increased the risk of all malignant tumours by 30 percent and astrocytomas in particular by 40 per cent.

Alasdair Philips, director of the campaign group Power watch, said studies like the Swedish one "highlighted the need to teach our children that mobile phone use can be very dangerous to their long-term health".

Instead of calling they should text or use "air-tube" hands-free headsets which eliminated the risk of radiation, he said.