A 30-year study of just about everyone in Scandinavia shows no link between mobile phone use and brain tumours.

The researchers reported in the Journal of the National Cancer Institute that even though mobile telephone use soared in the 1990s and afterward, brain tumours did not become any more common during this time, Isabelle Deltour of the Danish Cancer Society and colleagues wrote that they did not detect any clear change in the long-term time trends in the incidence of brain tumours from 1998 to 2003 in any subgroup.

The study looked at annual incidence rates of two types of brain tumour, glioma and meningioma, among adults aged 20 to 79 from Denmark, Finland, Norway, and Sweden from 1974 to 2003. Over the 30 years, nearly 60,000 patients were diagnosed with brain tumours. However if mobile phones gave you cancer then in the mid-1990s after afterwards.

They did see a small, steady increase in brain tumours, but it started in 1974, long before mobile phones existed. That might have been because tumours were spotted by better types of brain scans. However Deltour's team warned that it sometimes takes longer than 10 years for tumours caused by mobile phones to turn up, that the tumours are too rare in this group to show a useful trend, or that there are trends but in subgroups too small to be measured in the study. In otherwords it is too soon to tell.