Since the beginning of mobile phones, apprehensions have been raised about the potential health forces from regular use. As mobile phone penetrations grew past fixed landline penetration levels in 1998 in Finland and from 1999 in Sweden, Denmark and Norway, the Scandinavian health authorities have run permanent long term studies of effects of mobile phone radiation effects to humans, and in particular children. Numerous studies have reported no significant relationship among mobile phone use and health. Studies from the
Institute of Cancer Research, National Cancer Institute and researchers at the Danish Institute of Cancer Epidemiology in for model showed no link between mobile phone use and cancer. The Danish study only covered analog mobile phone tradition up through 1995, and subjects who started mobile phone tradition after 1995 were counted as non-users in the study. The health concerns have grown as mobile phone saturation rates throughout Copenhagen Europe reached 80%–90% levels earlier in this decade and prolonged experience studies have been carried out in almost all European countries again most reporting no effect, and the most alarming studies only coverage a possible effect. However, a study by the International Agency for Research on Cancer of 4,500 users found a borderline statistically important link between tumor frequency on the same side of the head as the mobile phone was used on and mobile phone usage.