Commentary Mobile Phones, Brain Tumors, and the Interphone Study: Where Are We Now? Anthony J. Swerdlow,1 Maria Feychting,2 Adele C. Green,3,4 Leeka Kheifets,5 and David A. Savitz6,7; International Commission for Non-Ionizing Radiation Protection Standing Committee on Epidemiology 1Section of Epidemiology, Institute of Cancer Research, Sutton, United Kingdom; 2Karolinska Institutet, Institute of Environmental Medicine, Stockholm, Sweden; 3Cancer and Population Studies Unit, Queensland Institute of Medical Research, Brisbane, Australia, 4School of Translational Medicine, University of Manchester, Manchester, United Kingdom; 5Department of Epidemiology, University of California at Los Angeles, Los Angeles, California, USA; 6Department of Community Health, and 7Department of Obstetrics and Gynecology, Brown University, Providence, Rhode Island, USA Background : In the past 15 years, mobile telephone use has evolved from an uncommon activity to one with > 4.6 billion subscriptions worldwide. However, there is public concern about the pos- sibility that mobile phones might cause cancer, especially brain tumors. o Bjectivs : We reviewed the evidence on whether mobile phone use raises the risk of the main types of brain tumor—glioma and meningioma—with a particular focus on the recent publication of the largest epidemiologic study yet: the 13-country Interphone Study. d iscuon : Methodological deficits limit the conclusions that can be drawn from the Interphone study, but its results, along with those from other epidemiologic, biological, and animal studies and brain tumor incidence trends, suggest that within about 10–15 years after first use of mobile phones there is unlikely to be a material increase in the risk of brain tumors in adults. Data for childhood tumors and for periods beyond 15 years are currently lacking. : Although there remains some uncertainty, the trend in the accumulating evidence is increasingly against the hypothesis that mobile phone use can cause brain tumors in adults. : brain cancer, cancer and radiation, epidemiology. Environ Health Perspect 119:1534–1538 (2011). http://dx.doi.org/10.1289/ehp.1103693 [Online 1 July 2011] c onclusi k ye sdrow In just 15 years the mobile phone has evolved from an uncommon, expensive, brick-shaped object used in restricted areas of Western countries to a convenient and ubiquitous part of modern life, with > 4.6 billion subscriptions worldwide (International Telecommunication Union 2010). The arrival of this mass tech- nology has been accompanied by some pub- lic and media concern about the possibility that the radiofrequency (RF) fields emitted by the phones might cause cancer, especially brain tumors. Numerous committees have considered the evidence and recommended more research (Independent Expert Group on Mobile Phones 2000; Scientific Committee on Emerging and Newly Identified Health Risks 2009). Since 1999, a series of epidemi- ologic studies of mobile phone use and can- cer have been published, mainly focused on brain tumor risks. Collectively, they have not provided evidence of a relationship, but they have had sufficient limitations to leave the question unresolved (Ahlbom et al. 2009). The Interphone study was launched in 2000 to provide a more powerful and methodologically rigorous investigation of this issue by collecting data in 13 countries. Now, 10 years and €19 million later, after much anticipation and a lengthy delay, the key results on brain tumors have been pub- lished (Interphone Study Group 2010). What should be made of them, considered along with the rest of the literature? Do we now know whether mobile phones cause brain tumors? If not, how much closer are we to knowing? 1534 The Interphone Study The Interphone study was an international, coordinated interview case–control study inves- tigating the potential effect of mobile phone use on the risk of the two most common types of brain tumor, glioma and meningioma (and, although not yet published, also acoustic neu- romas and parotid gland tumors). The study used a common core questionnaire and to some extent a common core protocol, but deviations and additions were allowed; for instance, cases were population based in most countries but hospital based in Japan and France, and controls were pair matched at nine centers but stratum matched in the other seven. These methodo- logical inconsistencies add to the difficulty of interpreting the overall results. Nevertheless, the multicenter structure enabled a study of exceptional size: > 5,000 patients with these relatively uncommon tumors were interviewed in a 5-year period—a considerable feat. The study questionnaire asked in detail about the type and pattern of use of each mobile phone the respondent had used and about other RF exposures and brain tumor risk factors. The questionnaire was adminis- tered by an interviewer using a computerized laptop data entry system (except in Finland), with practical advantages but with the disad- vantage that no original paper records were available to check the fidelity of data entry for apparently erroneous values. The questionnaire collected information on hands-free phone use, which was excluded from analyses because head exposure would then be negligible. It is unknown, however, how well subjects can recall past use of hands-free devices or whether recall differed between cases and controls. The analyses employed post hoc matching of one control per case (two for Germany) for the centers that had used a stratified control selection. The individual matching was then used for the analyses. This resulted in loss of data: 70 cases and > 2,000 interviewed con- trols were not included in the final analyses. Furthermore, most of the national studies that contributed to Interphone covered a wider age range (as low as 18 and/or up to 69 years) Address correspondence to A.J. Swerdlow, Section of Epidemiology, Institute of Cancer Research, 15 Cotswold Rd., Sutton, Surrey SM2 5NG, UK. Telephone: 44-2087224012. Fax: 44-2087224019. E-mail: anthony.swerdlow@icr.ac.uk Supplemental Material is available online (http:// dx.doi.org/10.1289/ehp.1103693). We thank S. Squires for secretarial help. This report was prepared under the auspices of the International Commission for Non-Ionizing Radiation Protection. The Institute of Cancer Research and Royal Marsden Hospital acknowledge funding to the National Institute for Health Research Biomedical Research Centre. A.C.G. is partly supported by UK Medical Research Council fellowship 89912. Funding for research undertaken by M.F. and A.J.S. has been pro- vided by a number of sources, including the European Fifth Framework Program; the International Union against Cancer, which receives funds from the Mobile Manufacturers’ Forum and the GSM Association; the Mobile Telecommunications Health and Research Programme; the Swedish Research Council; AFA Insurance; and VINNOVA (Swedish Governmental Agency for Innovation Systems). VINNOVA received funds from TeliaSonera, Ericsson, and Telenor. All funds from commercial sources were provided via firewalls. The authors certify that their freedom to design, conduct, interpret, and publish research was not compromised by any sponsor. A.J.S. holds shares in the telecom companies Cable and Wireless Worldwide and Cable and Wireless Communications. A.J.S.’s wife holds shares in the BT group, a global telecommunications services company. M.F., A.C.G., and A.J.S. are members of the International Commission on Non-Ionizing Radiation Protection, an independent body setting guidelines for nonionizing radiation protection. M.F. and A.J.S. serve as advisers to a number of public advisory and research steering groups concerning the potential health effects of exposure to nonionizing radiation. L.K. has advised electric utilities as well as regulatory and governmental bodies on the potential health effects of exposure to RF exposure. The other authors declare they have no actual or potential com- peting financial interest. Received 18 March 2011; accepted 29 June 2011. ovlume 119 | number 11 | November 2011 • Environmental Health Perspectives