A major new study has found no increased risk of brain tumours with long-term use of mobiles. However, although the data, collected from nearly 360,000 Danish mobile phone users, are reassuring, the researchers noted that the design of the study focused on mobile phone subscriptions rather than actual use, so it is unlikely to settle the debate over mobile safety.
A small to moderate increase in risk of cancer among heavy users of mobile phones for 10 to 15 years or longer still "cannot be ruled out", the researchers wrote.
The findings, published in the British Medical Journal as an update of a 2007 report, comes nearly five months after a World Health Organisation panel concluded that mobile phones are "possibly carcinogenic".
Last year, a 13-country study called Interphone also found no overall increased risk but reported that participants with the highest level of mobile phone use had a 40pc higher risk of glioma, an aggressive type of brain tumour.
Even if the elevated risk of glioma is confirmed, the tumours are relatively rare, and thus individual risk remains minimal.
The study is considered important because it matches data from a national cancer registry with mobile phone contracts beginning in 1982, the year the phones were introduced in Denmark, until 1995.
However, a major weakness of the study is that it counted mobile phone subscriptions rather than actual use by individuals, and failed to count people who had corporate subscriptions or who used mobile phones without a long-term contract.