Thousands being interviewed in mobile phone brain cancer study
Thousands of young people are being interviewed as the EU backs the largest study in the world into the links between mobile phone use and brain cancer in children.
Brain cancer is the most common type of cancer in children, after leukaemia. In the UK alone, some 450 children under the age of 18 are diagnosed with brain tumours every year.
Many people are tempted to blame the spiralling use of mobile phones. A study conducted at the beginning of this decade on behalf of the European Commission’s Directorate-General for Health and Consumers found that more than two-thirds of people in the EU believe their health is affected to some extent by mobile phone masts and mobile phone handsets.
Previous studies have not found any strong links between mobile phones and cancer, but according to Professor Elisabeth Cardis at the Centre for Research in Environmental Epidemiology in Barcelona, Spain, that may be because brain cancers are rare, and because heavy phone usage is a fairly recent phenomenon. ‘The fact of not seeing a trend does not mean there is no risk,’ she said. ‘It means if there is a risk, perhaps you haven’t had enough statistical power to be able to see it.’
Prof. Cardis coordinates MOBI-KIDS, a study that aims to find out whether more data will uncover a link. Backed by the EU’s FP7 funding programme, which runs from 2007 to 2013, the project is drawing on expertise from 16 European and non-European countries to discover if children who spend a lot of time on the phone are more likely to develop brain tumours.
Next year, researchers will complete the first major stage of MOBI-KIDS, which has involved interviewing some 6 000 young people between 10 and 24 years of age. One-third of the people are those with brain tumours, while the remaining two-thirds are control cases: people who are the same age and sex as counterparts in the first group, but who have not been diagnosed with brain cancer.
The interviews will explore the amount and the ways in which the subjects have used mobile phones. If mobile phones do increase the risk of brain cancer, then there ought to be marked differences between the two groups in terms of their past mobile phone usage.
MOBI-KIDS is not the first study to investigate the effect of mobile phones on health. In 2011, the International Agency for Research on Cancer (IARC) concluded there was ‘limited’ evidence that heavy usage – defined then as 30 minutes a day for 10 years – increased the risk of brain cancer.
Prof. Cardis, who previously ran the IARC radiation programme, said the IARC report could not be conclusive because of ambiguities in the data. One problem was asking people to recollect whether they held their mobile phone on the same side of the head in which their tumour was located.
‘If you’re asking people who have just been diagnosed with a brain tumour about their mobile phone use, they might have read in the press that mobile phones cause cancer,’ said Prof. Cardis. ‘So they might be more likely to say, “Ah, yes, I was using it on that side”.’
‘If there is a risk, perhaps you haven’t had enough statistical power to be able to see it.’
Prof. Cardis is hoping to avoid such ‘recall bias’ in MOBI-KIDS by asking less direct questions. ‘For instance, we can ask instead: “Show us how you use your mobile phone”,’ she said.
Jonathan Samet, an epidemiologist at the University of Southern California in Los Angeles, US, who is not involved in the project, calls children a ‘key population’ for which the risks of mobile phones should be investigated. ‘The study will fill in a gap in research, which has largely focused on brain cancer in adults,’ he said.
Prof. Cardis expects the first results from MOBI-KIDS to be ready by 2016. So what if the project gives strong evidence that mobile phones can cause brain cancer?
Another FP7-backed project is looking at ways to greatly reduce public exposure to electromagnetic fields generated by mobile phones, base stations and other wireless technologies. Last year, 17 leading telecommunications operators, vendors, research centres and academic institutions grouped together to form LEXNET, which aims to cut electromagnetic-field exposure by 50 %.
One of the ways LEXNET will do this, according to project manager Joe Wiart, is by examining the sum of incoming and outgoing signals. Since it is the mobile phones and not the base stations that generate the most concentrated electromagnetic fields, it may be possible to reduce exposure by increasing the density of base stations, so that the mobile phones do not have to work so hard.
Wiart expects LEXNET to finish in two years. ‘The objective is to reduce the exposure without any impact on quality of service,’ he said.
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