commentary Last week's press release from the World Health Organisation (WHO) set alarm bells ringing and had many mobile phone users reaching for their hands-free headsets, but is there really cause for concern? A 40 per cent increase in the risk of cancer for phone owners is a terrifying prospect, especially in a country like Australia where phone subscriptions outnumber our population. But is this really what the WHO is suggesting?
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Before we continue, this article needs a major disclaimer. We have no credentials that qualify us to either approve or criticise the findings of any of the professionals who have collected and analysed the data referred to by the WHO, and articles that we refer to express the opinions of individuals and publications who, while being experts in their fields, give only a personal analysis of the information.
What is the WHO actually saying about phones and cancer?
On 31 May, the WHO released a statement titled "IARC classifies radiofrequency electromagnetic fields as possibly carcinogenic to humans". The statement highlighted some of the latest findings of the Interphone research group, which included one study that suggested "a 40 per cent increased risk for gliomas in the highest category of heavy users"; that is, users who made at least 30 minutes of mobile phone calls per day for a period of 10 years. In response to these findings, the WHO has now included mobile phone use in its category 2B, the third of five categories of agents observed by the WHO that could be carcinogenic, graded by the severity of the risk that each poses.
The conclusions drawn by the WHO after the recent meeting of the international working group on the carcinogenicity of phone use, Interphone, are similarly inconclusive. The group's chairman, Dr Jonathan Samet, says that "the evidence, while still accumulating, is strong enough to support a conclusion and the 2B classification. The conclusion means that there could be some risk, and therefore we need to keep a close watch for a link between cell phones and cancer risk".
The 2B classification is defined by the WHO as "possibly carcinogenic to humans", and currently includes 266 other possibly carcinogenic agents in the list, including coffee, gasoline, pickled vegetables and various agents exposed to fire-fighters, dry cleaners and those working in textile manufacturing.
"This category is used for agents for which there is limited evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals ... In some instances, an agent for which there is inadequate evidence of carcinogenicity in humans ... together with supporting evidence from mechanistic and other relevant data may be placed in this group".
This is two steps below category 1, which includes well-known cancer causing nasties such as cigarette smoke and gamma radiation.
The press release has sparked a strong response from the scientific medical community, most of whom object to the mainstream media's interpretation of the statement rather than the findings themselves. Science Blog contributor Orac published an excellent analysis, not only explaining what the re-categorisation of phone use by the WHO means, but also putting the spotlight on some of the more outrageous claims in the media. Orac also highlights the difficulties faced by the working group in collecting data for the study.
This is all a bit confusing, but with the information at hand we intend to continue using our phones as we always have. The WHO's decision to re-categorise phone use to its 2B classification appears to indicate its intention to pursue the issue, that it won't rule out any possibilities, but it doesn't recommend that we toss our phones in the bin. If you're really cautious, using the hands-free headphones that came with your phone should be sufficient to minimise any risk.