In arriving at this conclusion, the working group relied heavily on the results of the Interphone Study, a 13-nation study sponsored by the WHO, and a series of studies conducted by Dr. Lennart Hardell in Sweden.
The journal Bioelectromagnetics recently published a "letter to the editor" which questions the 2B classification (1). Although the letter makes a few valid points — most laypersons don’t understand the meaning of “possibly carcinogenic” or “40% risk increase” — the authors' intent seems to be to undermine the credibility of the IARC working group’s review of the health effects of exposure to radio frequency energy. In his science blog on mobile phone radiation and health, Dr. Dariusz Leszczynski has called this letter, "A travesty of science."
The letter is a polemic which argues that the IARC working group should have been composed of members “who are not involved in the EMF field” to avoid conflicts of interest. The authors recommend that scientific review panels be composed of individuals who have no expertise in the specific field of study under review — a rather odd solution to this age-old problem.
Ironically, the authors cite Dr. Ahlbom’s work to dismiss Dr. Hardell’s research; yet, Dr. Ahlbom was the scientist with the undisclosed conflict of interest. Dr. Ahlbom opted not to attend the IARC working group meeting after WHO informed him he could not chair the epidemiology subgroup after Mona Nilsson, a Swedish investigative journalist “outed” him for his undisclosed associations with the cellular industry.
The authors failed to discuss the results published in Appendix 2 of the major Interphone study paper which finds that after correcting for one of the study biases the 40% risk increase for the heavy cellphone use group becomes an 80% risk increase.
The authors also failed to mention the peer-reviewed research that has been published since the IARC working group was convened in 2011. These more recent studies provide greater evidence of the carcinogenicity of cell phone radiation.
Why are the authors of this paper so motivated to dismiss the science and the consensus of the 30-member IARC working group (not counting the member from our National Cancer Institute who walked out of the meeting in protest)? One must wonder whether the authors disclosed all of their conflicts of interests?
In May 2011, the International Agency on Cancer in Research (IARC) issued an official statement concluding that cell phone usage was “possibly carcinogenic to humans.” There have been considerable doubts that non-experts and experts alike fully understood what IARC’s categorization actually meant, as “possibly carcinogenic” can be interpreted in many ways. The present study is based on an online survey indicating that both the characterization of the probability of carcinogenicity, as well as the description of the risk increase given in the IARC press release, was mostly misunderstood by study participants. Respondents also greatly overestimated the magnitude of the potential risk. Our study results showed that IARC needs to improve their scientific communications.
Using Survey Monkey (Palo Alto, CA), an online survey consisting of 13 questions was conducted in April 2012. Information about this on-going survey and the opportunity to participate was made available to all 27,000 students of the University of Innsbruck in Austria. A total of 2,013 students with a mean age of 24.5 years participated, with 66% of the respondents being female and 34% male. The students were from a wide variety of academic disciplines, and participation was anonymous and voluntary. The survey used parts of the original IARC  press release as stimulus material. Participants were instructed to read the text from the original IARC press release: “The WHO/International Agency for Research on Cancer (IARC) has classified radiofrequency 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. The IARC  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 (using their phones for 30?min per day over a 10-year period).”
… We asked, “What does a 40% risk increase mean?” and “How many additional cases will suffer from cancer?” Respondents could choose between five answers (1) 1 in 4, (2) 4 in 10, (3) 4 in 100, (4) 1 in 40, and (5) a number >0. As shown in Figure 2, the majority of respondents interpreted a 40% risk increase as 4 in 10. The correct answer depends on the baseline, that is, the normal brain cancer incidence in the population studied. Since IARC does not present any baseline information, a number >0, is the only meaningful answer to the information provided from Text 1. Figure 2 shows that only about 10% of the respondents picked the correct category (N?>?0).
…The relative risk statement should be strengthened by information on the incidence rate expressed as the number of new cases per unit of population per year. Given that the incidence of adult glioma is approximately 4.7 per 100,000 persons a year, a 40% increase in risk would mean an additional 1.9 cases of glioma per 100,000 people each year.
… A good 2B narrative should address the issues of who, why and what follows from the 2B classification. The “who” refers to the need to characterize the authors of the classification. The key issue here is that the credibility of the classification of RF fields depends on trust in the process and in the people who conducted the classification. There should be some concern that there are working group members who are the very researchers assessing the quality of their own studies. This would be a reason for people to question the credibility of the classification. A solution to this credibility issue for IARC could be to more thoroughly determine and account for the various potential conflicts of interest and to search for potential working group members without such conflicts. An example could be to select working group members who are not involved in the EMF field to conduct a truly independent review.
… The Interphone Study noted that: “Overall, no increase in risk of glioma or meningioma was observed with use of mobile phones. There were suggestions of an increased risk of glioma at the highest exposure levels, but biases and error prevent a causal interpretation.” IARC claims this is a positive study according to their definition when the study authors do not. This is a credibility issue. This existing ambiguity in the 2B-evidence base opens IARC’s classification to contrasting interpretations and opinions. From a communications standpoint, it is necessary to clearly and transparently inform about the pro and contra arguments for the classification based on the selected evidence. The other positive study  was clearly demonstrated  to be an outlier compared with the majority of other epidemiological studies. While IARC’s definition of 2B was technically complied with, because two epidemiology studies showed positive results, there is considerable doubt about the interpretation of what is a positive effect.
… The central message of the present study is that IARC needs to improve their current scientific communications, and in doing so, keep within its mandate vis-à-vis its parent WHO. We believe that focusing, for example, on adding a quantitative explanation to verbal probability expressions or using comparisons and narratives could help to ensure that everyone understands the state of the scientific findings and their underlying uncertainty. This may also enable all parties to draw the necessary conclusions for future health policy activities.
Conflicts of interest: The Science Forum EMF, founded by Peter Wiedemann, is a project of the Institute for Technology Assessment and Systems Analysis (ITAS) at the Karlsruhe Institute of Technology (KIT), a member of the Helmholtz Association of German Research Centres.