Schüz J, Elliott P, Auvinen A, Kromhout H, Poulsen AH, Johansen C, Olsen JH, Hillert L, Feychting M, Fremling K, Toledano M, Heinävaara S, Slottje P, Vermeulen R, Ahlbom A. An international prospective cohort study of mobile phone users and health (Cosmos): Design considerations and enrolment. Cancer Epidemiol. Aug 30, 2010. Ahead of print.
There is a significant public and scientific interest in possible health effects of exposure to radiofrequency electromagnetic fields (RF EMFs) emitted from wireless communication devices. In a recent risk assessment based on epidemiological, experimental animal and in vitro studies, the European Commission has concluded that exposure to RF below the current guidelines is unlikely to increase the risk of cancer. However, there is no certainty as to whether longer-term RF exposure (over 10 years) can pose any cancer risk. Data for non cancer diseases are scarce and inconclusive.
To overcome limitations of existing case-control studies on RF and disease risk (in particular the INTERPHONE study on RF and intracranial tumors), a large prospective cohort study (“Cosmos” study) of mobile phone users has been designed with participation of five European countries – Denmark, Finland, Sweden, The Netherlands, and the UK.
The aim of the Cosmos study is to recruit 250,000 men and women aged 18 years and over and follow them for more than 25 years. Information on mobile phone use will be collected at baseline and then periodically using questionnaires and traffic data provided by network operators. Traffic data will be collected for a 3-month period each year for each participant. Information on occurrence of diseases (cancer, neurological and cerebro-vascular diseases) will be collected from disease registries that exist in the participating countries. Medical history, potential confounders and health outcomes that are not collected by registries (symptoms, physical and mental well-being) will be assessed from baseline and follow-up questionnaires.
Results, Interpretation and Conclusion
Pilot studies were conducted to optimize the study protocol. Different approaches resulted in response rates ranging from 5.1% to 25.6%. Because in a prospective cohort study exposure is assessed before the occurrence of a health outcome, the participation is unlikely to influence exposure disease-association and is less of a concern for the study validity than in a case-control study. The main Cosmos study was launched in Denmark in November 2007. Regular meetings of principal investigators allow adaptation of the protocol to changing conditions. The study is open to further partnership under the condition that minimum requirements to data availability are met.