10. Conclusions on electromagnetic fields
- 10.1 Conclusions on Radio Frequency (RF) fields
- 10.2 Conclusions on Intermediate Frequency (IF) fields
- 10.3 Conclusions on Extremely low frequency (ELF) fields
- 10.4 Conclusions on static magnetic fields
- 10.5 Conclusions on environmental effects
- 10.6 Research recommendations
10.1 Conclusions on Radio Frequency (RF) fields
Radio frequency fields (100 kHz - 300 GHz) are for instance generated by mobile telephony and wireless networks.
The question receiving most attention is whether radio frequency field exposure causes cancer.
The balance of epidemiologic evidence still indicates that mobile phone use of less than 10 years does not pose any increased risk of cancer. Regarding longer use, it is still difficult to make an estimate since few persons had used mobile phones for more than ten years.
New improved studies looking into a possible link between radio frequency fields from broadcast transmitters and childhood leukaemia provide evidence against such a link.
Laboratory studies on animals show that radio frequency fields similar to those from mobile phones, alone or in combination with known carcinogens, do not increase the number of cancers in laboratory rodents. Certain studies have also employed higher exposure levels (up to 4 W/kg), still with no apparent effects on tumour development. Furthermore, the in vitro studies on cell cultures found no evidence that radio frequency field exposure could contribute to DNA-damage.
Evidence from studies on humans, animals and cell cultures concur that exposure to radio frequency fields is unlikely to lead to an increase in cancer in humans. However, as the widespread exposure of humans from mobile phones has been shorter than the time needed to induce some forms of cancers, further studies are required to identify whether human exposures to such phones well beyond ten years might pose some cancer risk.
Present scientific knowledge suggests that self-reported symptoms such as headaches, fatigue, dizziness or concentration difficulties affecting some individuals are not linked to exposure to radio frequency fields. These results suggest a “nocebo” effect, an effect caused by the expectation or belief that something is harmful. There is no evidence that individuals are able to perceive radio frequency fields.
There is some evidence that radio frequency fields can influence brain activity and sleep in humans. However, the health relevance is uncertain and how this may occur is not yet explained. Further investigation of these effects is needed. Other studies focusing on different aspects of the nervous system show no or no consistent effects. More...
10.2 Conclusions on Intermediate Frequency (IF) fields
Intermediate frequency fields (300 Hz – 100 kHz) are generated by sources like computer screens and anti-theft devices.
Exposure to intermediate frequency fields at the work place is in some cases considerably higher than exposure to the general public. However, very little research on intermediate frequency fields and health risks in occupational settings or for the general public has been published and the data are still too limited for an appropriate risk assessment.
In view of the increasing exposure to intermediate frequency fields at the work place, for instance in shops and certain industries, it is important that research in this area is given priority. More...
10.3 Conclusions on Extremely low frequency (ELF) fields
Extremely low frequency fields (below 300 kHz) are generated by sources like power lines, and electric appliances.
The conclusion that extremely low frequency magnetic fields are a possible carcinogen, chiefly based on childhood leukaemia results, is still valid. Laboratory studies on cell tissues have not yet provided an explanation of how exactly these fields might cause leukaemia.
No consistent relationship between extremely low frequency fields and self-reported symptoms such as fatigue, headache, and concentration difficulties has been demonstrated.
For some other diseases, notably breast cancer and cardiovascular diseases, recent research indicates that a link with extremely low frequency fields is unlikely. For yet other diseases, such as those affecting the brain and spinal cord, the issue of a link to ELF fields remains open and more research is called for.
New epidemiological studies indicate a possible increase in Alzheimer's disease arising from exposure to extremely low frequency fields. Further epidemiological and laboratory investigations of this observation are needed.
Recent animal studies suggested effects on the nervous system for relatively strong fields of 0.10-1.0 mT. However, there are still inconsistencies in the data, and no definite conclusions can be drawn concerning potential effects on human health.
Very few recent in vitro studies on cell cultures have investigated effects from extremely low frequency fields on diseases other than cancer and those available have very little relevance. There is a need for hypothesis-based studies on cell tissues (in vitro studies) to examine specific diseases. More...
10.4 Conclusions on static magnetic fields
Although a fair number of studies have recently been published there is still a lack of adequate data for a proper risk assessment of static magnetic fields. More research is needed, especially to clarify the many mixed and sometimes contradictory results.
Short term effects have been observed primarily on sensory functions for acute exposure. However, there is no consistent evidence for lasting adverse health effects from short term exposure up to several teslas. More...
10.5 Conclusions on environmental effects
The current database is inadequate for the purposes of the assessment of possible risks due to environmental exposure to radio frequency, intermediate frequency and extremely low frequency fields. More...
10.6 Research recommendations
To fill the important gaps in knowledge the following research efforts are recommended.
Radio frequency (RF) fields (100 kHz – 300 GHz)
- To study potential cancer risks, a long term cohort study is needed that would follow the health of a large population group and overcome problems of previous assessments, limited to short periods or head tumours.
- Health effects on children of exposure to radio frequency fields should be studied, taking into consideration the fact that the amount and distribution of energy absorbed in children may differ from that in adults.
- The total exposure of individuals to radio frequency fields should be assessed using high quality personal exposimeters, devices carried by individuals to measure their exposure to electromagnetic energy over time.
- Important findings such as those on damage to genetic material or on effects on the nervous system need to be confirmed by additional studies.
Intermediate frequency (IF) fields (300 Hz – 100 kHz)
Data on possible health effects from intermediate frequency fields are sparse. This issue should be addressed both through epidemiological and experimental studies.
Extremely low frequency (ELF) fields (less than 300 Hz)
- Epidemiological studies indicate an increased risk of leukaemia in children exposed to ELF fields. However, there is a lack of supporting evidence for such an effect either in animal models or in vitro studies or mechanistic investigations. This discrepancy must be resolved.
- Epidemiological and experimental investigations of the apparent association between ELF and the development of Alzheimer's disease should be given priority.
- Laboratory studies on animals and cell cultures are needed to determine possible effects at low exposures and establish dose-response relationships.
Static fields (0 Hz)
- A cohort study is recommended that would follow the health personnel dealing with equipment, such as MRI scanners, that generates strong static magnetic fields.
- Experimental studies are also needed on other potential effects, including cancer, damage to genetic material as well as developmental and neurobehavioural effects.
Studies of mechanisms of action in cells and tissues are needed at exposure levels lower than those causing tissue heating for radio frequencies and nerve and muscle excitation for extremely low frequencies, since there is still no generally accepted model of action of electromagnetic fields at those levels.