There is no association between risk of early childhood cancers and a mother's exposure to a mobile phone base station during pregnancy, concludes a new study published on today.

This is the first study to look at phone masts in Britain as a whole and is the largest of its kind.

Use of mobile (cellular) phones has increased markedly in recent years and questions have been raised about possible health effects, including brain and other cancers, especially after prolonged use. Surveys also indicate high levels of public concern about the potential risks of living near mobile phone masts.

Previous reports of apparent cancer clusters near mobile phone base stations are difficult to interpret due to small numbers and possible biases that could have affected the results. Also, any radiobiological explanation for such cancer excesses is lacking.

So researchers at Imperial College London set out to investigate the risk of early childhood cancers, such as brain tumours and leukaemia, and proximity to a mobile phone base station during pregnancy.

They identified 1,397 British children aged 0-4 years registered with leukaemia or a tumour in the brain or central nervous system between 1999 and 2001. Each case was matched to four controls from the national birth register. Data on all mobile phone base station antennas across Britain from 1996-2001 were also obtained.

Birth address was then used to estimate distance (in metres) from the nearest mobile phone base station, total power output for base stations within 700m of birth address and power density for base stations within 1400m of birth address.

The researchers found no association between cancer risk in young children and mobile phone base station exposures during pregnancy.

The authors acknowledge that their focus was early childhood cancers and therefore did not include longer term or other potential health effects that have been associated with mobile phone use. However, they conclude: The results of our study should help to place any future reports of cancer clusters near mobile phone base stations in a wider public health context.

In an accompanying editorial, John Bithell from the Childhood Cancer Research Group at the University of Oxford, says that clinicians should reassure patients not to worry about proximity to mobile phone masts. Moving away from a mast, with all its stresses and costs, cannot be justified on health grounds in the light of current evidence, he writes.