The World Health Organization (WHO) bases its recommendations to adopt a precautionary approach on demographic studies of childhood leukaemia. The reason why researchers and WHO distinguish between adult and childhood leukaemia is that research has demonstrated that the causes of adult and childhood leukaemia very probably are completely different.

Research findings do not indicate a cancer risk for adults, neither in connection with magnetic fields in homes nor in the workplace. Where breast cancer is concerned, for example, research findings point direct to a possible risk. This view is also supported by Danish studies of cancer incidence and causes of death (related to occupational exposure to magnetic fields) conducted among 30,000 employees in the electricity supply industry. The studies did not point to any cancer risk associated with magnetic fields.

Fields in the workplace are stronger than fields in the home
Magnetic fields in the workplace are often much stronger than the ones found in homes close to power lines. It would therefore be quite natural to expect that possible health risks manifested themselves more clearly in such studies than in studies solely dealing with people that live or used to live near power lines.

The studies of Danish employees in the electricity supply sector are part of a doctoral dissertation by consultant doctor, MD and PhD Christoffer Johansen from the Danish Cancer Society (2004), and they were most recently updated and expanded in 2007. The expanded study covers a longer period of time than the first study from 1998. In the most recent study, researchers have also used a further improved model to assess the strength of the fields to which the study participants have been exposed.