Mobile phones are not associated with an increased risk of the most common type of brain tumour, according to the findings of the first UK study of the relationship between mobile phone use and risk of glioma.

A four-year study by the Universities of Nottingham, Leeds and Manchester, and the Institute of Cancer Research, London, found those who had regularly used a mobile phone were not at a greater overall risk of developing this type of tumour. The research is published online by the British Medical Journal.

There was no relationship between the risk of glioma and number of years since first use of a mobile phone, lifetime years of use and cumulative number of calls or hours of use. Risk was not associated with phone use in rural areas, which had been found to be associated with an increased risk in an earlier Swedish study.

A significantly increased risk was found for tumours which developed on the same side of the head as the phone was reported to have been held, but this was mirrored by a decrease in the risk on the opposite side of the head — making it difficult to interpret as a real effect.

This finding may be due to people with glioma brain tumours linking mobile phone use to the side of the tumour and therefore over-reporting the use of a phone on the same side as their tumour. This results in under-reporting use on the opposite side of the head, say the authors.

Professor Kenneth Muir, of the Division of Epidemiology and Public Health at Nottingham University Medical School, is a co-author of the paper.

Mobile phones have been available in the UK since 1985, but widespread use did not begin until the late 1990s making the number of long term users (over ten years) quite small. This study had limited numbers for estimating the risk of using a phone over a long period.

Early mobile phones were designed to use analogue signals and emitted higher power than current digital phones but the study showed no increased risk of glioma brain tumours with the use of analogue phones.

The study authors concluded: “This study suggests that there are no substantially raised risks of glioma in the ten years after first mobile phone use. Only future studies will be able to address longer latency periods for the development of glioma.”