Cancer is one of the most common causes of disease and death globally. The causes for initiation and tumor progression of malignant tumors (carcinogenesis) are known in some cases (e.g., asbestos or smoking for lung cancer), however they are not yet often discovered despite intensive research.
In the lower range of the electromagnetic spectrum, Wertheimer and Leeper observed an increased incidence of childhood leukemia in the vicinity to 50/60 Hz magnetic fields of power transmission lines in 1979. This finding initiated several studies in different countries for further investigation of the possible association by applying different methods of exposure assessment. The overall conclusion based on the results of the partly contradicting studies was that the risk for childhood leukemia was possibly twice as high for exposure to a magnetic field with a long-time average of 0.4 microTesla. In 1999 the International Agency for Research on Cancer (IARC) classified extremely low frequency magnetic fields as "possible human carcinogen" (Group 2B) in the same group as caffeine although there was no known biological mechanism despite intensive laboratory research.
The carcinogenic effects of ionizing radiation such as UV, X-rays and gamma radiation ranging in the upper part of the electromagnetic spectrum were investigated and verified in experimental and epidemiological studies. Based on the evidence of these findings, the IARC classified ionizing radiation as "carcinogenic to humans" (Group 1).
The exponentially increasing use of mobile phones in the past 15 years and the undisclosed effects of extremely low frequency magnetic fields led to the investigation of possible effects of the waves in the middle part of the electromagnetic spectrum used in mobile communication. If the use of a mobile phone would increase the risk for cancer, then a large number of humans worldwide would be affected. Therefore, a large number of studies were initiated: 1. medical/biological studies to disclose the possible action mechanism of mobile communication exposure on organisms under standardized laboratory conditions and to supply proven results concerning a possible association, and 2. epidemiological studies to investigate the possible association between mobile phone use and cancer incidence within the population.
The aim of the CEFALO study is to investigate whether the use of mobile phones increases the risk of developing brain tumors in children and adolescents in the age group 7-19 years. The multinational case-control studies were conducted in Denmark, Sweden, Norway and Switzerland in the time period 2004 to 2008. The results will be published at the end of 2009.
In 2008, the international cohort study of mobile phone use and health (COSMOS) was initiated as a long-term project to investigate the possible association between long-term mobile phone use and adverse health effects. The five European countries of the UK, Denmark, Sweden, Finland, and the Netherlands participated in study.
The international multi-centre MOBI-KIDS study was initiated in 2009 to investigate the relationship between communication technologies including mobile phones factors and brain cancer in young people. Over a study period of five years, nearly 2000 young people between 10 to 24 years with brain tumours and a similar number of young people without a brain tumour will be invited to participate in the study. Research groups of following countries are involved from the start: Australia, Austria, Canada, France, Germany, Greece, Israel, Italy, New Zealand, Spain, Taiwan, and the Netherlands.