There are over 4,000 new cases of brain tumours per year of which glioma is the most common type. Early symptoms include headaches and feelings of nausea; but the causes of these tumours are currently unknown. Fears have been expressed that mobile phone use might be a factor.
The four year study by the Universities of Leeds, Nottingham 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.
There was no relationship for risk of glioma and time since first use of a mobile phone, lifetime years of use and cumulative number of calls and hours of use. Risk was not associated with phone use in rural areas which was 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.
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 10 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.