Classification of high-frequency electromagnetic fields by the IARC

In May 2011, the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) analysed the current knowledge of high-frequency electromagnetic fields and cancer illnesses and classified these fields into Group 2B "possibly carcinogenic" on the IARC scale. This classification means that according to the estimation of the IARC, based on current knowledge, there are limited indications that high-frequency electromagnetic fields have a carcinogenic effect on humans. Group 2B also includes pickled vegetables and approximately 250 more substances. Since 2002, low-frequency fields have also been classified as "possibly carcinogenic".

Classification based on limited evidence from epidemiological and animal studies

From the viewpoint of a working group convened by the IARC at the time, high-frequency electromagnetic fields could possibly be carcinogenic. This, however, has not yet been scientifically proven. Rather, the classification is based on limited evidence from epidemiological studies on humans and on limited evidence from laboratory tests on animals.

In relation to humans, studies were rated as informative and taken into consideration only if a localised exposure of the head had actually occurred. The exposure conditions corresponded to those that occur during the use of mobile or cordless telephones. A causal connection between mobile phone exposure and gliomas (malignant brain tumours) as well as acoustic neuromas (tumours of the auditory nerve) has been estimated as possible, evidence for other types of tumour is regarded as insufficient.

In contrast to this, the available epidemiological studies on occupationally exposed persons have been judged by the IARC working group to be methodically limited and their results as inconsistent. The evidence for an association between environmental exposure to high-frequency electromagnetic fields (for example, from base stations) and cancer has been classified as inadequate. Among the numerous studies that were not considered for classification were investigations concerning other brain tumours, leukaemia, lymphomas, choroid tumours, testicular, breast, lung and skin cancer.

In experimental studies on animals, one out of 7 long-term studies showed an increased number of tumours. In genetically altered and/or cancer-sensitive animal models, there was an increased incidence in 2 of 12 studies and a cancer-promoting effect in 1 of 18 studies.

Research by the BfS

Within the framework of the German Mobile Telecommunication Research Programme, and in follow-up studies the BfS has investigated the indications regarding possible carcinogenic effects of radiofrequency electromagnetic fields. The evidence for carcinogenicity could not be confirmed in the studies initiated or partially financed by the BfS. Two recently completed studies are particularly noteworthy.

• The MOBI-Kids study investigated a possible association between wireless phone use of children and adolescents and brain tumours. The MOBI-Kids findings support results of existing studies that there is no robust scientific evidence that mobile phone radiation increases the risk of brain cancer.
• A second study commissioned by the BfS investigated a possible association between the development of mobile phone use over time and the incidence of glioma over time. The results of this study do not support an increase in the risk of glioma from mobile phone use. Due to some limitations of this study, however, the BfS recommends further investigating an association between glioma risk and mobile phone use.

A tumour-promoting effect has been observed in one animal model, but the effect was not evident in others. In addition, the results cannot be directly extrapolated to humans.

The Federal Office for Radiation Protection has ascertained that according to current knowledge, no health impairments are to be expected from high-frequency fields – for example from mobile communications – if limit values are adhered to. There are, however, still uncertainties regarding the possible long-term effects of high-frequency electromagnetic fields on humans. Epidemiological studies published to date do not allow a conclusive statement to be made on the cancer risk for a period of use of more than 15 years, in particular on the risk of brain tumours in "heavy users". So far, there has been no noticeable increase in the incidence rates of head tumours in the national cancer registries.

The Federal Office for Radiation Protection is one of five international scientific WHO collaborating centres, responsible among others for mobile communications. In this function, the BfS advocates continuous and forceful investigation of the remaining open questions related to the health effects of mobile communications.

Until the outstanding issues are finally clarified, the Federal Office for Radiation Protection continues to demand, in addition to the existing legal regulations, more high-quality research and comprehensive information for the population, including possibilities for preventive exposure reduction. The Federal Office for Radiation Protection is active in the fields of research, evaluation and information itself and provides information on possibilities for preventive exposure reduction in the individual handling of mobile phones as well as smartphones and tablets.

Revaluation by the IARC

In April 2019 the "IARC Monographs Advisory Group" published a recommendation for future IARC monographs. The WHO is currently funding ten systematic reviews in which possible health effects of high-frequency electromagnetic fields are examined and in which the BfS is also partially involved. After completing the systematic reviews, the IARC will reassess high-frequency electromagnetic fields with high priority.