The use of mobile phones over a long period of time can raise the risk of brain tumors, according to a Swedish study released recently said.
A Reuters report also said the new study contradicted the conclusions of other researchers.
Reports said last year, the Dutch Health Council, in an overview of research from around the world, found no evidence that radiation from mobile phones and TV towers was harmful.
A four-year British survey in January also showed no link between regular, long-term use of cell phones and the most common type of tumor.
But researchers at the Swedish National Institute for Working Life looked at mobile phone use of 2,200 cancer patients and an equal number of healthy control cases, the Reuters report said.
The report said of the cancer patients, aged between 20 and 80, 905 had a malignant brain tumor and about a tenth of them were also heavy users of mobile phones.
'Of these 905 cases, 85 were so-called high users of mobile phones, that is they began early to use mobile and/or wireless telephones and used them a lot,' a statement from the researchers, quoted by Reuters, said.
Published in the International Archives of Occupational and Environmental Health, the study defines heavy use as 2,000 plus hours, which 'corresponds to 10 years' use in the work place for one hour per day.'
Early use was defined as having begun to use a mobile phone before the age of 20.