USING a mobile phone for more than 10 years does not appear to raise the risk of brain tumours, according a new study that re-opens the debate on the safety of the devices. Researchers found that there was no significant increase in the incidence of cancer among adults who have been using them for up to a decade. They found that there was no change in rates between 1998 and 2003 compared with the previous two decades. The findings, which come from a study of the populations in Denmark, Finland, Norway and Sweden, all of which are heavy phone users, appears to contradict the expected results of another long term study. A 20million, decade-long investigation overseen by the World Health Organisation (WHO) is expected to publish evidence soon that heavy users face a higher risk of developing brain tumours later in life. In the latest study, Dr Isabelle Deltour, of the Institute of Cancer Epidemiology, Danish Cancer Society, and colleagues analyzed annual incidence rates of tumours among adults aged 20 years from Denmark, Finland, Norway, and Sweden. Researchers identified 60,000 patients who were diagnosed with these types of brain tumours between 1974 and 2003. The researchers found that incidence rates over this 30 year-period were stable, decreased, or continued a gradual increase that started before the introduction of cell phones. They also found no change in incidence trends in brain tumors from 1998 to 2003. The results, published in the Journal of the National Cancer Institute, back up the Department of Healths view of mobile phones. It has not updated its guidance for more than four years. It says that the current balance of evidence does not show health problems caused by using mobile phones, and suggests only that children be discouraged from making non-essential calls while adults should keep calls short. In contrast, several other countries, notably France, have begun strengthening warnings and American politicians are urgently investigating the risks. Telegraph