Decision against a German COSMOS study

The COSMOS study

COSMOS (Cohort Study of Mobile Phone Use and Health) is an international population-based cohort study. The study investigates the possible health effects of the long-term use of mobile phones and other wireless devices that use high-frequency electromagnetic fields (HF-EMF). The COSMOS study was launched in 2007 and is currently being carried out by an international consortium of six European countries: Denmark, Finland, France, the Netherlands, Sweden, and the United Kingdom. In the study, data on the telecommunications behaviour, lifestyle, and health of the participants is collected and collated via questionnaire and from other sources. With regard to mobile phone use, most epidemiological studies to date show no increased risk for the occurrence of tumours in general or for tumours in the head, neck, and throat area in particular. However, the study situation does not yet allow a conclusive statement on the risk of brain tumours in frequent users of mobile communications. A conclusive statement on the cancer risk after more than 15 years of mobile phone use is also not possible because of the still comparatively short period of use of this technology.

Examination of German participation in the COSMOS study

Even before the start of the international study, the Federal Office for Radiation Protection (BfS) was considering German participation. After completing a feasibility study in 2005, the BfS decided against participation in 2006 because of the low level of willingness among the general population and the resulting recruitment effort and costs. The German NAKO health study (formerly the National Cohort), which has been running for several years now, has provided a new, more efficient way of recruiting participants and collecting data for the German COSMOS study. The BfS therefore re-examined whether German participation in co-operation with the NAKO would make sense. After a detailed examination, the BfS concluded that the objectives and topics of the study are still relevant. However, especially because of the late start of a German study and the resulting problems with regard to recording exposure and necessary exposure contrasts, which are explained in more detail below, it is unlikely that a German COSMOS study will be able to make a substantial contribution determining whether the exposure to mobile end devices investigated has negative health consequences.

Problems in assessing exposure

Through the current mobile communications technology, it is no longer possible to determine the exposure from mobile communications devices with sufficient accuracy in order to be able to investigate a causal relationship between this and possible health effects. At the beginning of the international COSMOS study, it was possible to reliably estimate exposure because the duration of use of the mobile phone provided a reliable measure of the exposure to the head. However, with the newer generations of mobile communications (UMTS (3G), LTE (4G), and 5G) and the various applications such as voice and video telephony, chat programmes, social media, and data traffic, the correlation between period of use and individual exposure is considerably weaker because many factors influence personal exposure. Using the measurement methods currently available, it would not be possible to assess current and future exposure in a sufficiently meaningful way within the framework of a cohort study. There is also no known model that can be used to calculate a suitable measure of the dose from the various use parameters. In addition, the lack of reliable information on the exposure of the participants before the start of the study would be problematic.

Problems with lack of exposure contrasts

In addition to exposure assessment, another problem is that the exposure contrasts at the head (i.e. the differences in exposure between frequent and infrequent users) have decreased considerably compared with the early days of mobile telephony. And a further decrease is to be expected. This is due to the increased use of mobile end devices and the associated lack of a non-exposed comparison group as well as the decreased frequency of high exposures to the head as a result of introducing newer mobile phone standards, expanding the networks, and modifying usage behaviour (e.g. through the increased use of headphones, loudspeakers, and chat programs).

Click on the following link for the full BfS assessment.

Expert discussion

In order to have the assessment of the BfS reviewed by external scientists, the BfS organised a meeting of experts on 1 December 2022.

Participants (external):

Dr M. Blettner (formerly IMBEI, University Medical Center of the Johannes Gutenberg University Mainz)
Dr A. Enders (TU Braunschweig)
G. Schmid (Seibersdorf Laboratories)
Dr J. Schüz (International Agency for Research on Cancer: Environment and Radiation)
J. Vogel (Federal Minister for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection)
Dr D. Wollschläger (IMBEI, University Medical Center of the Johannes Gutenberg University Mainz)
Dr H. Zeeb (Leibniz Institute for Prevention Research and Epidemiology – BIPS)

Participants (BfS):

Dr P. Scholz-Kreisel (WR3, Radiation epidemiology and risk assessment)
T. de las Heras Gala (WR3, Radiation epidemiology and risk assessment)
Dr C. Enzenbach (KEMF, Competence Centre for Electromagnetic Fields)
Dr M. Kreuzer (WR, Effects and risks of ionising and non-ionising radiation)
Dr J. Kuhne (KEMF, Competence Centre for Electromagnetic Fields)
Dr E. Saathoff (WR3, Radiation epidemiology and risk assessment)
Dr M. Schnelzer (WR3, Radiation epidemiology and risk assessment)
Dr G. Ziegelberger (KEMF, Competence Centre for Electromagnetic Fields)

Overall, the experts thought that, despite the great importance of the ongoing COSMOS study, the additional scientific benefit of a German COSMOS study starting now is rather uncertain because of the problems discussed. Overall, they were opposed to conducting the study, thereby confirming the assessment of the BfS. However, the investigation of the health effects of mobile communications was still considered to be highly relevant. In addition to radiation effect aspects, social and cognitive aspects (e.g. concentration disorders, sleep disorders, and psychological stress caused by media), which do not fall within the scope of radiation protection, are also becoming more important. Exposure assessment and dosimetry are also to be improved. The EU is already funding several projects in this area.

Conclusion

Following a thorough internal and external review, the BfS will not conduct a German COSMOS study. Nevertheless, the BfS will continue to actively research the possible health effects of HF-EMF. Among other things, the focus will be on improving exposure assessment and developing new ways to monitor changes in exposure over time.