We're still no closer to determining if mobile phone use increases your chances of getting brain cancer, say experts.
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LYON: Radiofrequency electromagnetic fields associated with wireless phone use have been classified as possibly carcinogenic by the World Health Organisation (WHO), however experts say the evidence is limited.
Over the last few years, there has been mounting concern about the possibility of adverse health effects resulting from exposure to radiofrequency electromagnetic fields, such as those emitted by wireless communication devices. The number of mobile phone subscriptions is estimated at five billion globally.
From 24-31 May 2011 a working group of 31 scientists from 14 countries met at the International Agency for Research on Cancer (IARC) - a part of the WHO - in Lyon, France, to assess the potential carcinogenic hazards from exposure to radiofrequency electromagnetic fields.
They considered hundreds of scientific articles to assess occupational exposures to radar and to microwaves; environmental exposures associated with transmission of signals for radio, television and wireless telecommunication; and personal exposures associated with the use of wireless telephones.
Jonathan Samet from the University of Southern California and chairman of the working group indicated 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."
Additional research needed
The evidence was reviewed critically, and overall evaluated as being limited among users of wireless telephones for glioma and acoustic neuroma, and inadequate to draw conclusions for other types of cancers. The evidence from the occupational and environmental exposures was similarly judged inadequate.
The working group did not quantitate the risk; however the WHO pointed to one study of past cell phone use (up to the year 2004), showed a 40% increased risk for gliomas in the highest category of heavy users (reported average: 30 minutes per day over a 10‐year period).
"Given the potential consequences for public health of this classification and finding, it is important that additional research be conducted into the long‐ term, heavy use of mobile phones," said IARC Director Christopher Wild. "Pending the availability of such information, it is important to take pragmatic measures to reduce exposure such as hands‐free devices or texting. "
Need studies on dose response
The study used three types of data - human observation, animal experimentation and mechanistic studies in the laboratory. While the mechanistic studies can show a change in the cells in action, they are limited in that they cannot show whether this change will affect health.
By combining mechanistic studies with human studies the scientists can overcome this problem, yet human studies are susceptible to different kinds of bias. The IARC committee worked mostly with the same set of information that was released last year, when glioma was identified as the only outcome with an increased risk from cell phone use.
