There are billions of mobile phone users worldwide. In the first quarter alone, 427.8 million mobile phone units were sold, according to market researcher Gartner. During the period, Nokia sold 107.6 million mobile devices, the largest brand, with a 25.1% market share worldwide. Apple is fourth, selling 16.9 million iPhones in the quarter. Gartner expects that more than 1.790 billion mobile phone units will be sold this year.

The World Health Organization's International Agency for Research on Cancer (IARC) has classified radio-frequency electromagnetic fields as possibly carcinogenic to humans (Group 2B), based on an increased risk for glioma, a malignant type of brain cancer, associated with wireless phone use.

According to WHO report, over the last few years, there has been mounting concern about the possibility of adverse health effects resulting from exposure to radio-frequency electromagnetic fields, such as those emitted by wireless communication devices. The number of mobile phone subscriptions is estimated at 5 billion globally.

From May 24 to 31, 2011, a Working Group of 31 scientists from 14 countries met meeting at IARC in Lyon, France, to assess the potential carcinogenic hazards from exposure to radio-frequency electromagnetic fields.

The IARC Monograph Working Group discussed and evaluated the available literature on the following exposure categories involving radiofrequency electromagnetic fields:

* 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.

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 mentioned above was similarly judged inadequate. The Working Group did not quantitate the risk; however, 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).

Dr Jonathan Samet of the University of Southern California, USA, overall Chairman of the Working Group, said "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."

"Given the potential consequences for public health of this classification and findings," said IARC Director Christopher Wild, "it is important that additional research be conducted into the long-term, heavy use of mobile phones. Pending the availability of such information, it is important to take pragmatic measures to reduce exposure such as hands-free devices or texting."

The Working Group considered hundreds of scientific articles; the complete list will be published in the Monograph. It is noteworthy to mention that several recent in-press scientific articles resulting from the Interphone study were made available to the working group shortly before it was due to convene, reflecting their acceptance for publication at that time, and were included in the evaluation.