Even if we're uncertain about their effects, we know enough to take precautions with mobile phones
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Do mobile phones really cause cancer?
7th June, 2011
Consumers have been left confused by the latest study on the links between mobile phone use and brain cancer. Eifion Rees reports on the struggle to find answers
one should try to decrease one’s exposure by keeping the phone away from the body and head
Sleek, stylish and indispensable are all words mobile phone companies would like consumers to associate with their devices. At the very bottom of the list is ‘cancer’.
But a new review of scientific evidence by a World Health Organization (WHO) body has reopened debate on the issue, just a year after another report appeared to have put it to bed.
The review, carried out by 31 international scientists from the WHO’s International Agency for Research on Cancer (IARC), led to the radiofrequency electromagnetic fields emitted by mobile phones being declared ‘possibly carcinogenic’.
The reclassification contradicts the findings of a 10-year investigation into links between mobile phones and cancer, published in 2010. The Interphone study of 13,000 people found no causal link between mobile phone use and four types of brain tumour, including glioma (although its authors conceded their findings were necessarily ‘biased’ and ‘limited’, depending as they did on participants recollections of their mobile use over time).
But nor is the new IARC report emphatic: evidence was ‘limited’ for the link with two specific brain cancers – glioma and acoustic neuroma – and ‘inadequate’ for all other cancers. The ‘possibly carcinogenic’ classification (group 2b) puts mobile phones into the same catch-all bracket as coffee, dry cleaning chemicals, chloroform and DDT.
Unsurprisingly the mobile phone industry has been downplaying the IARC findings.
‘[This] does not mean cell phones cause cancer,’ said John Walls of the Wireless Association (CTIA). ‘Under IARC rules, limited evidence from statistical studies can be found even though bias and other data flaws may be the basis for the results.’
‘The IARC classification suggests that a hazard is possible but not likely,’ said Dr Jack Rowley of the mobile communication association GSMA, speaking for most of the major mobile companies. ‘This comprehensive scientific review identified some suggestive evidence in the human studies but no consistent support from animal and cell studies.’
He added that present safety standards remained valid and said the IARC report ‘should be understood as indicating the need for further research’ over a long period of time.
Sony Ericsson said the IARC had found mobiles were ‘neither a definite nor a probable cause’ of cancer, and said the results were consistent with the vast majority of research showing ‘no conclusive evidence’ of a cancer connection.
Nokia said all its products comply with international exposure guidelines and limits set by public health authorities, and pointed out that the IARC’s conclusions – that mobile phone radiation was ‘[not] definitely nor even probably carcinogenic to humans’ – were based on limited evidence.
Mobile phones pass 5 billion mark
So who can consumers trust? The importance of establishing the facts once and for all is cast into stark relief by the sheer weight of numbers involved: a study by Ericsson in July estimated that the number of mobile devices globally will top 50 billion by 2020. The 720 million mobile phone subscriptions there were in 2000 has swollen over a decade to 5 billion.
A 250,000-strong cohort study is already underway in Europe. Conducted by Imperial College London in the UK, 68,000 people have signed up since COSMOS launched last year; their mobile phone use and health will be monitored for 20-30 years, with initial results published in 2015. The research has been endorsed as a priority by global agencies including the WHO, Department of Health (DoH) and the EU’s Scientific Committee on Emerging and Newly Identified Health Risks.
COSMOS research associate Rachel Smith said mobile phones had not been around long enough for any conditions that might be associated with their use to develop; nor have previous studies looked at potential adverse effects beyond brain cancer.
‘There is currently scientific uncertainty about a relatively new and widespread technology. To address this, the most responsible step society can take ... is due diligence by beginning to monitor the health of a large number of mobile phone users over a long period of time.’
According to Cancer Research UK, incidences of brain cancer in the UK have not risen as mobile phone use has increased, nor have similar trends been seen in studies from the US, New Zealand and Scandinavia. Indeed, it indicates that the pooled estimate of the many reports on mobile phones over the years shows no statistical increase in brain cancer – the positive and negative reports effectively balance each other out.
Frank de Vocht, a lecturer in occupational and environmental health at the University of Manchester and co-author of one of those reports – which found that a rise in mobile phone use in England 1985-2003 had no noticeable impact on the incidences of brain cancer 1998-2007 – stresses that all studies should be considered part of the evaluation process, rather than looked at in isolation.
He welcomes a ‘very balanced’ IARC decision based on all current available scientific evidence, including the Interphone study, his own paper and a 2006 report from Sweden’s Hardell Group that found mobile phone use increased the risk of brain cancer.
‘What it in my opinion [the report] indicates is that while the overall evidence indicates there may be a risk for glioma, it remains unclear what the biological mechanism for this link would be. Nor does it seem to be a very strong link, although the IARC monograph programme does not make a judgment on the magnitude of the risk. For other cancer there is no evidence of carcinogenicity.
‘When new studies become available to fill in gaps in knowledge the risk may remain the same, be increased or even decreased in future evaluations.’
But some experts suggest that not all reports are equal. Dr Henry Lai, a research professor in bioengineering at the University of Washington specialising in the biological effects of electromagnetic fields, says those with industry backing are not dependable.
‘I surveyed the cell phone research literature and found that phone-industry-funded research tended to find no effect, compared to non-industry-funded research. This does make reports backed by mobile phone companies questionable.’ He cites reports published in the journals Environmental Health Perspectives and Comptes Rendus Physique to support his unofficial data.
'No clear evidence' say health officials
Despite the IARC reclassification, the government is not set to make any immediate change to its advice on mobile phone use. A DoH spokesperson said its position had always been ‘to adopt a precautionary approach’ and warned that children should only use mobile phones for essential purposes and keep calls short.
Any change will depend on advice given by the Health Protection Agency (HPA), whose Advisory Group on Non-Ionising Radiation is currently engaged in its own review of radiofrequencies, which will be published within the next 12 months.
A spokesperson for the HPA said while there is ‘no clear scientific evidence’ of a link between mobile phones and brain cancer, ‘the possibility remains’, adding that the advisory group had been asked to take the IARC classification into account.
‘If one worries about the possible brain cancer-causing effect of cell phone use, one should try to decrease one’s exposure by keeping the phone away from the body and head, using a wired headset or texting rather than calling,’ says Henry Lai.
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