Commentary: Call me on my mobile phone … or better not?—a look at the INTERPHONE study results

Mobile phone (cell phone) use is increasing extraordinarily rapidly worldwide. There are now 4.6 billion mobile phone subscribers worldwide. In many lowand middle-income countries use of cell phones has made communications possible in vast areas lacking cable connections. Increasingly, in high-income countries, cell phones have replaced ‘land lines’ for personal telecommunications. Users of mobile phones are exposed to electromagnetic radiation, which has long been hypothesized to have adverse health effects, including increased risk of cancer. Research on biological mechanisms of cellular and tissue injury by electromagnetic radiation has been inconclusive, and consequently epidemiological studies have been the principal source of evidence on potential health risks of mobile phone use. Brain tumours have been of particular concern because the electromagnetic radiation generated by mobile phones passes through the brain when the phones are used without a hands-free device. To date, findings of diverse studies on mobile phone use and brain tumour risk have been reported with mixed findings, but with no clear indication of increased risk for cancer. To provide needed evidence on the potential risk of brain cancer associated with mobile phone use, the International Agency for Research on Cancer (IARC) initiated a multi-centre case–control study, the INTERPHONE study, in 1998–99. A much awaited report from this large international study on mobile phone use and brain tumours is published in this issue of the IJE. A number of previous papers cited in the article reported only partial findings from components of the multicentre study, heightening expectations on what the full data set would eventually show. The component studies were relatively underpowered, but they exhibited a rather consistent and baffling reduced risk among cell phone users. We now have the complete results and the researchers’ interpretation of them. The INTERPHONE investigators conclude that ‘There were suggestions of an increased risk of glioma, and much less of meningioma, at the highest exposure levels, for ipsilateral exposures and, for glioma, for tumours in the temporal lobe. However, biases and errors limit the strength of the conclusion we can draw from these analyses and prevent a causal interpretation’. This statement, as with a similar one (‘. . .these biases and errors prevent a causal interpretation of the results.’) at the end of the Appendix 2 of the article added during the editorial process of revision, is both elegant and oracular. Similar to any oracle it tolerates diametrically opposite readings. If more weight is given to the first sentence, a conclusion is reached in favour of an increased risk, albeit not definitively manifest yet, from intensive use of mobile phones. Giving more weight to the second sentence leads to the conclusion that there are enough sources of errors in the study to dismiss the apparent elevated risks as not real. With equal weight to the two sentences, any conclusion hangs in the balance. Is there any way out of this ambivalence? INTERPHONE is the largest study yet carried out and published on mobile phone use and cancer. It includes 2409 cases of meningioma, 2708 cases of glioma and two series of, respectively, 2662 and 2972 controls matched by age, sex and region of residence. With the coordination of IARC it has mobilized investigators in multiple centres within 13 countries ‘ . . . to determine whether mobile phone use increases the risk of [brain] tumours and, specifically, whether radiofrequency energy emitted by mobile phones is tumorigenic’. Certainly this is the question that scientists, people and public health decision-makers have in mind, as This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/