Context

After the introduction of digital mobile phone systems in the 1990s, a growing number of people were using these devices that raised concerns about possible health consequences because even small risks could be of public health relevance if the number of exposed were large. A surge of controversy about possible health effects of radio frequency electromagnetic fields occurred and, although the majority of scientists maintained the view that mobile phone use was safe, possible health effects began to be studied in epidemiological, animal experimental and in vitro investigations. In this context the Danish cohort study was initiated in the mid-1990s.