Electric and Magnetic Fields

Effect on Human Health

For over 40 years, scientists have been investigating the possible effects of EMFs on human health. Hundreds of epidemiological studies have been conducted on various groups, including electric utility workers and the general public. In addition, numerous laboratory studies have been conducted on the effects of fields on the living cells of various animal species as well as humans.

To date, no studies have been able to show that fields at the levels found in the home or workplace have any clear effect. However, some doubt persists as to whether a relatively weak magnetic field (0.4 µT) could increase the risk of childhood leukemia. Data on the subject remain contradictory.

Research on the effects of 60-Hz electric and magnetic fields on human health

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Research at the cellular level has not revealed any marked effect of magnetic fields at levels of less than 50 µT. Experimental studies on animals have not shown any toxic effect at exposure levels of 5,000 µT, which are between 25,000 and 100,000 times higher than normal household levels.

No adverse effects have been reported on general health or on animal behavior. In humans, short- and mid-term exposure to magnetic fields does not appear to cause symptoms such as headaches, difficulty concentrating, chronic fatigue or dizziness.

Expert opinions on the general health effects of magnetic fields

A number of opinions on the health effects of EMFs have been issued by experts mandated by national public institutions or international agencies, or by specialists acting on their own behalf. Here are the most recent:

Federal Provincial Territorial Radiation Protection Committee (2008)

The Federal Provincial Territorial Radiation Protection Committee is a federal committee under the aegis of Health Canada whose mission is to advance the development and harmonization of practices and standards for radiation protection within Federal, Provincial and Territorial jurisdictions. The Committee has posted on its Web site a response statement to public concerns about EMFs from electrical power transmission and distribution lines. This statement includes the following:

"...there is insufficient scientific evidence showing exposure to EMFs from power lines can cause adverse health effects such as cancer. Therefore, a warning to the public to avoid living near or spending time in proximity to power lines is not required."

Health Canada (2012)

Health Canada is the federal department in charge of health matters in Canada. Its Web site contains a great deal of information on health and safety issues of interest to the general public. One page is dedicated to EMFs at extremely low-frequencies. Part of the site reads as follows:

"Health Canada does not consider that any precautionary measures are needed regarding daily exposures to EMFs at ELFs. There is no conclusive evidence of any harm caused by exposures at levels found in Canadian homes and schools, including those located just outside the boundaries of power line corridors"

World Health Organization (2007)

The World Health Organization (WHO) is a United Nations agency that specializes in health matters. In 1996, it launched the International EMF Project for the purpose of assessing the effect of EMF exposure on health and the environment. The project is being carried out in cooperation with national and international research agencies and institutes. On its Web site, WHO states:

"In October 2005, WHO convened a Task Group of scientific experts to assess any risks to health that might exist from exposure to ELF electric and magnetic fields in the frequency range 0 to 100,000 Hz (100 kHz). (...) Following a standard health risk assessment process, the Task Group concluded that there are no substantive health issues related to ELF electric fields at levels generally encountered by members of the public."

For magnetic field, WHO concludes:

"Regarding long-term effects, given the weakness of the evidence for a link between exposure to ELF magnetic fields and childhood leukaemia, the benefits of exposure reduction on health are unclear."

Video (2013): Electric and magnetic fields: Over 40 years of scientific studies

In 1996, the World Health Organization set up a vast project to study electric and magnetic fields.

Michael Repacholi led this project from 1996 to 2006.

Video (2013): Electric and magnetic fields: A Québec study

In this field, the experimental studies done on animals are very important. Scientists can expose animals to very high magnetic field levels under controlled conditions.

One of the very first studies of this kind was conducted here in Québec. It was led by Dr. Rosemonde Mandeville from the Institut Armand-Frappier, and the results of the study were published in 1997.

In vitro studies have not shown any genetic effects or mechanisms that might explain how magnetic fields could transform a normal cell into a cancerous one; nor have long-term animal studies shown magnetic fields to have any carcinogenic effect. While the findings of epidemiological studies are not as clear-cut, the largest of them have not shown any link between residential or workplace exposure to magnetic fields and the risk of cancer.

Experimental studies on animals

Experimental studies using standard carcinogenicity evaluation protocols have been conducted on rats and mice of both sexes. The maximum exposure levels were as high as 1,000 and even 5,000 µT, and the duration of exposure ranged from 18 to 22 hours a day over periods of up to two years. All these studies included complete histopathological analyses for the purpose of detecting tumors in various organs. None of them showed any evidence that magnetic fields had a significant carcinogenic effect.

Another hypothesis put forward is that magnetic fields do not increase the incidence of cancer themselves, but rather modify the effect of another carcinogen. Over 20 animal studies have been carried out so far to test this hypothesis, subjecting animals to a known carcinogen and then to magnetic fields. As a whole, the results have been negative.

For more information on animal studies investigating the carcinogenicity of magnetic fields

Since 1997, four long-term animal studies involving seven separate investigations of magnetic fields have been published. The first was conducted by the team of Dr. R. Mandeville (Mandeville et al., 1997) at the Institut Armand-Frappier in Québec, Canada. Four groups of female rats were exposed for 20 hours a day for their whole lives to magnetic fields of 2, 20, 200, and 2,000 µT (2,000 µT is about 13,000 times the ambient magnetic field inside a home). These groups of rats were compared to control groups living in the same laboratory conditions but without significant exposure to magnetic fields. At the end of the rats' exposure period, nearly 50 organs and tissue samples were analyzed to look for benign and malignant (i.e., cancerous) tumors. The animals most exposed to magnetic fields were not found to have any more tumors than the unexposed animals.

The second study, also published in 1997, was conducted in Japan by a team from the Mitsubishi Kasei Institute of Toxicological and Environmental Sciences, under the direction of Dr. Y. Otaka. The study involved both male and female rats (Yasui et al., 1997). At 5,000 µT, the maximum exposure level was higher than in the Québec study. Here too, no increase in the number of tumors was observed in the exposed animals compared with the control group.

The two other studies, both published in 1999, were carried out in the United States in cooperation with the National Institute of Environmental Health Sciences and used traditional protocols for evaluating carcinogenicity (Boorman et al., 1999; McCormick et al., 1999). The maximum exposure level was 1,000 µT. One study exposed male and female rats to magnetic fields, while the other used male and female mice. Again, the researchers concluded that there was little or no indication that exposure to magnetic fields increased the incidence of tumors.


Epidemiological studies – Magnetic fields and cancer in children

Regarding magnetic fields and childhood leukemia, certain epidemiological studies have reported a relative risk of 1.5 to 2.5, particularly when children's exposure was estimated based on the presence of power lines near their home. However, other studies whose findings were based on actual measurements of magnetic fields in children's homes, found no such association. Pooled analyses of high-quality epidemiological studies seem to show that the risk of leukemia is greater for children with residential exposure to magnetic fields of over 0.3 or 0.4 µT. However, the authors of these analyses express serious reservations concerning the methods they used to examine the studies and pool their results. In addition, a meta-analysis has demonstrated that exposure to magnetic fields does not increase the risk of brain cancer in children.

For more information about these analyses

Analysis of A. Ahlbom
In 2000, a pooled analysis regarding a possible association between childhood leukemia and exposure to magnetic fields was carried out by researcher Anders Ahlbom. It was based on nine epidemiological studies where exposure to magnetic fields had been measured or calculated, and it included data from the three largest studies published so far (Linet et al., 1997; McBride et al., 1999; Cheng et al., 1999). The nine studies covered a number of countries (the United States, Canada, the United Kingdom, Sweden, Denmark, Finland, Norway, Germany and New Zealand), all of which had unique exposure profiles. By pooling these analyses and their subjects, the study was able to compare the exposure levels of 3,203 children with leukemia and those of 10,338 children in good health. The findings show that exposure to magnetic fields of less than 0.4 µT does not increase children's risk of developing leukemia, whereas exposure to fields of 0.4 µT and more doubles the risk. However, the authors do not exclude the possibility of selection bias for children with leukemia and control children in at least one of the nine studies—which could provide a partial explanation for the results of this pooled analysis.

Analysis of S. Greenland
The same year, researcher Sander Greenland directed another pooled analysis on the same subject. This second analysis looked at data from 12 epidemiological studies, including Linet et al. (1997) and McBride et al. (1999). The studies were conducted in the same countries as those in Ahlbom's analysis, and in this case the levels of exposure of 2,656 children with leukemia were compared with those of 7,084 children in good health. According to the analysis, exposure to magnetic fields weaker than 0.3 µT does not increase children's risk of developing leukemia, whereas exposure to fields of 0.3 µT and more leads to increased risk. Here too, the authors do not exclude the possibility that the results could be affected by arbitrary selections and differences in magnetic field measurement techniques.

Analysis of G. Mezei
In 2008, researcher Gabor Mezei directed a meta-analysis of the possible link between childhood brain cancer and magnetic field exposure. Results from 13 epidemiological studies in which magnetic field exposure was either measured or calculated were analyzed. The studies covered a number of countries (the United States, the United Kingdom, Norway, Sweden, Denmark, Finland, Taiwan and Japan), all of which had unique exposure profiles. Pooling the subjects of these 13 studies made it possible to compare exposure levels of 9,196 children with brain cancer and 12,348 children in good health. The findings show that exposure to magnetic fields does not increase the risk of childhood brain cancer.

For more information about epidemiological studies on cancer in children and exposure to magnetic fields

A total of 26 epidemiological studies on exposure to magnetic fields and childhood cancer have been conducted. They are not all of the same quality, but the most recent ones used the best methodologies available and looked at very large populations in order to produce more accurate results. The studies looked primarily at leukemia and brain cancer. In children, these are among the most common forms of cancer.

None of the largest studies, carried out in the United States, Canada and Great Britain, demonstrated a higher risk of leukemia in children with the greatest exposure to magnetic fields. The studies that reported a greater risk were chiefly those in which exposure was estimated on the basis of the presence of power lines near the children's homes, whereas the studies that used real measurements of magnetic fields in the children's homes showed no such association.

The U.S. study was conducted in nine states under the direction of Martha Linet of the National Cancer Institute (Linet et al., 1997). It looked at 638 cases of lymphoblastic leukemia, the type most common in children. The researchers used two approaches to gauge exposure to magnetic fields. The first was to compare magnetic field levels measured in the children's homes. The second was to compare the density of power lines (the proximity, number and size of conductors) near children's homes, as in the studies mentioned above. It used the wire-coding system developed by Nancy Wertheimer, the author of the first study on the subject, published in 1979 (Wertheimer and Leeper, 1979). Contrary to several previous studies, this study showed no association between power line density near the children's homes and the risk of leukemia [relative risk (RR) = 0.88; confidence interval (CI) = 0.48–1.63, for the highest-density category]. Based on fields measured in the homes, no statistically significant association was observed between the risk of leukemia and the children's weighted average exposure to magnetic fields for the initial exposure categories defined in the study. For children exposed to fields of over 0.2 µT, the relative risk was 1.24 (CI = 0.86–1.79). A significant increase in risk was noted at a higher exposure level (0.4–5 µT), but the risk decreased at still higher exposure levels. The authors conclude that their results provide little support for the hypothesis that exposure to 60-Hz residential magnetic fields increases the risk of childhood leukemia.

The Canadian study, directed by Mary McBride of the British Columbia Cancer Agency, is a similar study that looked at 399 cases of childhood leukemia in five Canadian provinces, including Québec (McBride et al., 1999). The researchers used the same two approaches (power line density around the home and real magnetic field measurements) as the previous study to estimate the exposure of cases and controls, but this time they had each child wear a measuring device for 48 hours. The results do not show any link with leukemia: the direct measurements indicate that the risk of developing leukemia does not increase with magnetic field strength (RR = 0.95; CI = 0.72–1.26), nor does it increase as the density of the power distribution system increases (RR = 1.16; CI = 0.58–2.3).

The British study, also published in 1999, was conducted by a large group of researchers brought together for the occasion under the banner of the UK Childhood Cancer Study Investigators (UKCCSI). It examined 995 cases of childhood leukemia in England, Wales and Scotland (Cheng et al., 1999). The researchers used the same approaches as in Linet's study to estimate the exposure of both cases and controls. The study's findings are similar to those of the U.S. and Canadian studies.

It is interesting to note that as a whole, the seven available studies which examined the risk of childhood leukemia and its relationship to real magnetic field measurements in the home offer little evidence that magnetic fields are a risk factor for the disease (Feychting and Ahlbom, 1993; Green et al., 1999; Linet et al., 1997; London et al., 1991; McBride et al., 1999; Michaelis et al., 1997; Savitz et al., 1988). Since magnetic field measurements inside the home take account not only of power lines outside the home but also all the sources inside the home, the risks calculated on that basis are probably more accurate than those which take only the presence of power lines near the house into account.

A few studies have investigated the relationship between household appliances and the risk of leukemia. As a whole, the results are negative. However, since this sort of exposure is usually minimal, the studies cannot really rule out an effect associated with long-term use. Their findings are not nearly as significant as those of the studies mentioned above.

The effect of exposure to magnetic fields on the risk of childhood brain cancer has also been the subject of a great deal of research. While earlier work led to rather contradictory results, more recent studies show no effect on the incidence of this disease.


Epidemiological studies – Magnetic fields and cancer in adults

Over a hundred epidemiological studies have been published on magnetic fields and cancer in adults. On the whole, the studies did not report any increase that could be attributed to occupational magnetic-field exposure. Nevertheless, a few studies did suggest that workers with the most exposure appeared to be at greater risk for leukemia and brain cancer. However, the findings are inconsistent, and the presumed risk appears to be relatively low. With respect to the relationship between cancer in adults and exposure to magnetic fields in residential environments, research published to date generally reports that the risk of cancer is no greater for adults living near high-voltage lines.

For more information about epidemiological studies on cancer in adults and exposure to magnetic fields

Data gathered from electric utility workers show that average magnetic field exposure levels for exposed workers are 10 to 15 times higher than at home. Dozens of studies have been conducted on these populations. Leukemia and brain cancer have received special attention because of possible links suggested by studies from the 1980s and studies involving children.

The vast majority of these studies were exploratory in nature and simply used workers' job titles to determine their level of exposure. However, six of them used high-quality methodologies, including field measurements made with specially designed dosimeters and the selection of a relatively homogeneous population of electric utility workers (Floderus et al., 1993; Sahl et al., 1993; Thériault et al., 1994; Savitz and Loomis, 1995; Harrington et al., 1997; Johansen and Olsen, 1998). The four most recent studies are particularly important because of the large number of cases. They looked at utility workers in Canada, France, the United States, Great Britain and Denmark.

Researcher Gilles Thériault, from McGill University's Department of Occupational Health, was scientific coordinator of the joint France-Canada study. It dealt with workers from Hydro-Québec, Ontario Hydro and Électricité de France. Professor David A. Savitz, of the University of North Carolina, coordinated the U.S. study on workers in five companies. The British study, directed by James M. Harrington, looked at employees of the CEGB, Great Britain's national electricity generating company (now dissolved and privatized). Researcher C. Johansen of the Danish Cancer Society directed the study of 99 electricity companies in Denmark. Despite their considerable scope and a distinct improvement in gauging levels of exposure, these studies did not provide any definitive answers to the questions asked.

In relation to brain cancer, only Savitz's study reported a statistically significant relative risk risk for workers with the greatest exposure (RR = 2.29), with a confidence interval (CI) of 1.15 to 4.56. This is similar to Thériault's findings (RR = 1.95; CI = 0.76–5.00) but does not agree with those of Sahl (RR = 0.84; CI = 0.54–1.33), Harrington (RR = 0.95; CI = 0.54–1.69) or Johansen (RR = 0.79; CI = 0.6–1.0,), who observed no increased risk.

In regard to leukemia, the findings are also conflicting. Thériault reports a non-significant risk of 1.75 (CI = 0.77–3.96) for the most exposed group of workers for all types of leukemia, and a statistically significant risk of 3.15 (CI = 1.20–8.27) for acute myeloid leukemia in workers whose exposure is greater than the median. However, Sahl and Savitz report no significant increase.

A few studies have also been carried out among adults living near HV lines. One study reported an increase in the incidence of leukemia (RR = 1.4; IC = 1.0–1.9) and no risk of brain or breast cancer in a population in Taiwan (Li et al., 1997). Most other studies do not show any significant risk. The main weakness in these studies is the method used to estimate the subjects' exposure to magnetic fields.


Expert opinions on magnetic fields and cancer

In Québec and Canada, the question of EMFs and the risk of cancer has caught the attention of public health authorities. Here are their opinions:

Federal Provincial Territorial Radiation Protection Committee (2008)

The Federal Provincial Territorial Radiation Protection Committee is a federal committee under the aegis of Health Canada Health whose mission is to advance the development and harmonization of practices and standards for radiation protection within Federal, Provincial and Territorial jurisdictions. The Committee has posted on its Web site a response statement to public concerns about EMFs from electric power transmission and distribution lines. This statement includes the following:

"...there is insufficient scientific evidence showing exposure to EMFs from power lines can cause adverse health effects such as cancer. Therefore, a warning to the public to avoid living near or spending time in proximity to power lines is not required."

Institut national de santé publique du Québec (2000)

The Institut national de santé publique du Québec (INSPQ) is an agency of the Ministère de la Santé et des Services sociaux du Québec (MSSS) whose mission is to provide specialized advice and assistance (including laboratory services), to conduct research and develop new knowledge, and to disseminate training and information. In 2001, the MSSS mandated the INSPQ to update scientific information on the risks associated with EMFs and to draw a conclusion. It also asked the agency to recommend maximum exposure levels for very-low-frequency EMFs and to prepare prudent management scenarios. To carry out this mandate, the INSPQ formed a group of experts. The report they presented reads in part as follows [translation]:

"[...] the risk of health effects from chronic exposure remains uncertain. After analyzing the scientific evidence, the task force considers that a causal link between chronic exposure to EMFs and the incidence of cancer (childhood and adult leukemia) has not been established. Nevertheless, given the absence of any clear explanations of inconsistencies in the findings of epidemiological studies, the existence of such a risk cannot be excluded."

Health Canada (2004)

Health Canada is the federal department in charge of health matters in Canada. Its Web site contains a great deal of information on health and safety issues that concern the general public. One page is dedicated to EMFs at extremely low frequencies. Part of the site reads as follows:

"There have been many studies about the effects of exposure to electric and magnetic fields at extremely low frequencies. Scientists at Health Canada are aware that some studies have suggested a possible link between exposure to ELF [extremely low frequency] fields and certain types of childhood cancer. […] [However,] when all of the studies are evaluated, the evidence suggesting that EMFs may contribute to an increased risk of cancer is very weak."

World Health Organization (2004)

The World Health Organization (WHO) is a United Nations agency specialized in health matters. In 1996, it launched the International EMF Project for the purpose of assessing the effect of EMF exposure on health and the environment. The project is being carried out in cooperation with national and international research agencies and institutes. On its Web site, the WHO states:

"Despite many studies, the evidence for any effect remains highly controversial. However, it is clear that if electromagnetic fields do have an effect on cancer, then any increase in risk will be extremely small. The results to date contain many inconsistencies, but no large increases in risk have been found for any cancer in children or adults. [...] A number of epidemiological studies suggest small increases in risk of childhood leukemia with exposure to low frequency magnetic fields in the home. However, scientists have not generally concluded that these results indicate a cause-effect relation between exposure to the fields and disease (as opposed to artifacts in the study or effects unrelated to field exposure). In part, this conclusion has been reached because animal and laboratory studies fail to demonstrate any reproducible effects that are consistent with the hypothesis that fields cause or promote cancer. Large-scale studies are currently underway in several countries and may help resolve these issues."

International Agency for Research on Cancer (2002)

The International Agency for Research on Cancer (IARC) is part of the WHO. Its mandate is to coordinate and conduct experimental and epidemiological studies on the causes of cancer. The agency's objectives are to track the worldwide incidence of cancer, to determine the causes, to elucidate the mechanisms of carcinogenesis and to develop scientific strategies for cancer control. In 2001, the IARC reviewed the available studies on cancer and 50- and 60-Hz EMFs, as well as static EMFs. The IARC concluded by classifying both static EMFs and 50- and 60-Hz AC electric fields as "not classifiable as to their carcinogenicity to humans." The IARC classified 50- and 60-Hz magnetic fields as Group 2B, "possibly carcinogenic to humans."

International Commission on Non-Ionizing Radiation Protection (1998)

The International Commission on Non-Ionizing Radiation Protection (ICNIRP) is a non-governmental organization that works in partnership with the WHO. Its mission is to analyze the risks of non-ionizing radiation for human health and to recommend exposure limits for workers and the general public. Its guidelines must be approved by the International Radiation Protection Association. In 1998, the ICNIRP updated its guidelines on 50- and 60-Hz EMF exposure limits. In its new guidelines, the ICNIRP states:

"In the case of potential long-term effects of exposure, such as an increased risk of cancer, ICNIRP concluded that available data are insufficient to provide a basis for setting exposure restrictions, although epidemiological research has provided suggestive, but unconvincing, evidence of an association between possible carcinogenic effects and exposure at levels of 50/60 Hz magnetic flux densities substantially lower than those recommended in these guidelines."

European Commission (2001)

The European Commission (EC) represents the common interests of European Union (EU) member states and is the main driving force behind its institutional system. Health is a major priority for the EC. The EC's public health program aims to prevent illness and disease as well as dangers to human health in the EU. The program identified the environment, including the presence of EMFs, as one of the key factors determining human health. In early 2001, the EC asked the Scientific Committee on Toxicity, Ecotoxicity and the Environment to update its evaluation of the health risks posed by EMF exposure. Late the same year, the Committee released its opinion on the subject:

"Combined analyses of the epidemiological studies on the association between exposure to ELF [extremely low-frequency electromagnetic fields] and childhood leukaemia have strengthened the evidence of an association. However, given some inconsistencies in exposure measurements and the absence of other criteria commonly used in assessing causality (particularly a plausible explanation of underlying biological mechanisms […]), the association does not meet adequate criteria for being considered causal. Thus the overall evidence for 50/60 Hz magnetic fields to produce childhood leukaemia must be regarded as being limited […] There is no convincing suggestion of any other carcinogenic effect of ELF on either children or adults."

Various countries have also mandated groups of specialists to look at this question. Here are some of their opinions:

National Institute of Environmental Health Sciences (1999)

The National Institute of Environmental Health Sciences (NIEHS) is part of the National Institutes of Health, an agency of the U.S. Department of Health and Human Services. In 1992, as part of the Electric and Magnetic Fields Research and Public Information Dissemination Program (EMF-RAPID), the U.S. Congress asked the NIEHS to clarify the potential for health risks from exposure to extremely low-frequency EMFs. In 1999, the NIEHS released its official report. One of its conclusions reads as follows:

"The scientific evidence suggesting that ELF-EMF [extremely low-frequency electromagnetic fields] exposure poses any health risk is weak. The strongest evidence for health effects comes from associations observed in human populations with two forms of cancer: childhood leukemia and chronic lymphocytic leukemia in occupationally exposed adults. While the support from individual studies is weak, the epidemiological studies demonstrate, for some methods of measuring exposure, a fairly consistent pattern of a small, increased risk with increasing exposure that is somewhat weaker for chronic lymphocytic leukemia than for childhood leukemia. In contrast, the mechanistic studies and the animal toxicology literature fail to demonstrate any consistent pattern across studies although sporadic findings of biological effects have been reported. No indication of increased leukemias in experimental animals has been observed."

Health Protection Agency (2005)

The Health Protection Agency (HPA) is an independent body reporting to the United Kingdom Department of Health. The HPA's mission is to protect the public from infectious diseases and dangers to health, such as hazardous chemicals, poisons or radiation. Initially, the agency's influence was limited to England and Wales. Following its merger with the National Radiological Protection Board (NRPB) in 2005, the HPA now serves the entire United Kingdom. The mission of its Radiation Protection Division is to conduct research to advance knowledge about protection from ionizing and non-ionizing radiation, to provide laboratory and technical services, to run training courses and to provide expert information. It also plays an important advisory role in the United Kingdom. On its Web site, the report on the association between the risk of cancer and extremely low-frequency EMFs (drafted in 2001 under the aegis of the NRPB) reads as follows:

"Laboratory experiments have provided no good evidence that extremely low frequency electromagnetic fields are capable of producing cancer, nor do human epidemiological studies suggest that they cause cancer in general. There is, however, some epidemiological evidence that prolonged exposure to higher levels of power frequency magnetic fields is associated with a small risk of leukaemia in children. […] In the absence of clear evidence of a carcinogenic effect in adults, or of a plausible explanation from experiments on animals or isolated cells, the epidemiological evidence is currently not strong enough to justify a firm conclusion that such fields cause leukaemia in children."


The findings of in vitro experimental studies and animal studies are largely negative. The epidemiological studies for which results are currently available have not demonstrated that magnetic fields have a significant effect on reproduction or pregnancy at typical levels to which the public is exposed. Some studies do show a few effects on pregnancy, but a number of these have serious methodological flaws.

Forty or so animal studies and thirty-odd epidemiological studies have dealt with the effects of extremely low-frequency magnetic fields on pregnancy and development of the foetus.

Generally speaking, the results of in vitro experimental studies and animal studies do not show any toxic effects at very high magnetic field exposure levels. In addition, conventional carcinogenesis studies on rodents exposed for their whole lives to magnetic field intensities of up to 5,000 µT have all been negative. This suggests that magnetic fields do not interfere in any substantial way with the systems regulating cell division (mitosis), a mechanism involved in both normal tissue maintenance and the development of tumors.

The few epidemiological studies that have looked into the effects of magnetic fields on pregnancy have reported certain statistical associations. However, these observations are not consistent from one study to the next and often reflect methodological weaknesses related to the selection or participation rate of subjects, or poor control of factors influencing how the pregnancy proceeds during data analysis. Moreover, they do not agree with the findings of experimental studies, which reported nothing of significance at much higher exposure levels. Finally, our current understanding of the mutagenic or genotoxic effects of extremely low-frequency EMFs suggests that they do not have any effect on germ cells, an additional factor that makes the effects observed in certain epidemiological studies even less plausible. Thus, although some epidemiological studies have found an association between the risk of childhood leukemia and the father's occupational exposure to magnetic fields, these data are difficult to reconcile with the negative results of carcinogenicity studies in mice whose parents had been exposed before and during their mating—in other words, during the males' spermatogenesis period—to field levels of up to 5,000 µT, or with the results of genotoxicity tests on mammals in which the exposure of male mice to levels of 10,000 µT or 20 kV/m had no mutagenic effect on their progeny.

Expert opinions on electric and magnetic fields and reproduction
World Health Organization (2004)

The World Health Organization (WHO) is a United Nations agency specialized in health matters. In 1996, it launched the International EMF Project for the purpose of assessing the effect of EMF exposure on health and the environment, carried out in cooperation with national and international research agencies and institutes. On its Web site, WHO states:

"Many different sources and exposures to electromagnetic fields in the living and working environment, including computer screens, water beds and electric blankets, radiofrequency welding machines, diathermy equipment and radar, have been evaluated by the WHO and other organizations. The overall weight of evidence shows that exposure to fields at typical environmental levels does not increase the risk of any adverse outcome such as spontaneous abortions, malformations, low birth weight, and congenital diseases. There have been occasional reports of associations between health problems and presumed exposure to electromagnetic fields, such as reports of prematurity and low birth weight of children of workers in the electronics industry, but these have not been regarded by the scientific community as being necessarily caused by the field exposures (as opposed to factors such as exposure to solvents)."


As a whole, epidemiological studies have not shown any association between exposure to magnetic fields and an increased risk of depression or suicide.

Most epidemiological studies carried out in either residential or occupational settings did not reveal any link between the proximity of power lines or exposure to magnetic fields and the risk of suicide. The few studies that reported such an association had methodological flaws, in particular a failure to take account of factors recognized as leading to suicide, such as depression, addiction, a difficult family life or a dysfunction of the serotonin system.

The most frequent cause of suicide is depression. At this time, the possible association between depression and exposure to magnetic fields has been the subject of very few studies, and the findings are mixed.

One synthesis of several studies concluded that any link between exposure to magnetic fields and the risk of suicide or depression was small.

For more information about this meta-analysis

Analysis of A. Ahlbom
In 2001, researcher Anders Ahlbom carried out several meta-analyses to determine if there was any link between exposure to EMFs and neurodegenerative diseases or psychological disorders. His analyses dealt with amyotrophic lateral sclerosis (seven studies), Alzheimer's disease (five studies), depression (six studies) and suicide (seven studies), and were carried out in a number of countries (United States, Canada, Great Britain, Sweden, Denmark and Finland). In the case of neurodegenerative diseases, the populations studied were mainly workers with occupational exposure to EMFs, whereas for depression and suicide, the population was made up of the general public as well as workers with occupational exposure.

The meta-analysis of seven studies dealing with amyotrophic lateral sclerosis (ALS, commonly called “Lou Gehrig's disease”) involved a total of 1,803 subjects with the disease. The findings revealed that working in an electric utility increased one's chances of developing ALS. The researcher concluded that exposure to EMFs could be one of several possible explanations. The meta-analysis of five studies on Alzheimer's disease (AD) looked at a total of 1,039 cases of people with the disease. According to the author, however, the results do not show any clear effect of EMFs on the incidence of AD.

With regard to depression and suicide, Anders Ahlbom believed that pooling the studies in question was not relevant because of the significant differences in their experimental protocols. As a result, he conducted a global analysis of the findings, and concluded that the association between exposure to EMFs and the risk of depression or suicide was rather tenuous.


Expert opinions on magnetic fields, depression and suicide
World Health Organization (2004)

The World Health Organization (WHO) is a United Nations agency specialized in health matters. In 1996, it launched the International EMF Project for the purpose of assessing the effect of EMF exposure on health and the environment, in cooperation with national and international research agencies and institutes. On its Web site, WHO states:

"Some members of the public have attributed a diffuse collection of symptoms to low levels of exposure to electromagnetic fields at home. Reported symptoms include headaches, anxiety, suicide and depression, nausea, fatigue and loss of libido. To date, scientific evidence does not support a link between these symptoms and exposure to electromagnetic fields. At least some of these health problems may be caused by noise or other factors in the environment, or by anxiety related to the presence of new technologies."



Certain epidemiological studies suggest a link between exposure to magnetic fields and the risk of developing amyotrophic lateral sclerosis, multiple sclerosis, Alzheimer's disease and Parkinson's disease. However, a review of the findings offers little support for the hypothesis that exposure leads to increased risk.

Epidemiological studies on the possible association between exposure to magnetic fields and the risk of developing amyotrophic lateral sclerosis (ALS) were carried out mainly among electric utility workers. Most magnetic field measurements made in these studies were indirect measurements, generally using job exposure matrices. As a whole, the results of these studies were inconclusive. Most of the studies that report increased risk were retrospective studies, whereas those which report no such increase were almost always prospective studies. The latter studies involved tracking large cohorts of up to 5 million individuals.

Like the studies on ALS, epidemiological studies on a possible link between magnetic field exposure and the risk of developing Alzheimer’s disease (AD) looked chiefly at workers with occupational exposure to magnetic fields. Workers’ exposure to magnetic fields was measured either directly, using measuring devices, or indirectly, generally using job exposure matrices. Here too, despite these considerable resources, the studies offer few conclusive findings as a whole.

Epidemiological studies investigating the possible association between exposure to magnetic fields and the risk of developing Parkinson’s disease or multiple sclerosis have not shown any such association to date.

On the other hand, one meta-analysis concluded that working in an electric utility increases an individual’s risk of developing ALS, and that exposure to magnetic fields is one possible cause among many. Another meta-analysis suggests an association between occupational exposure to EMFs and the risk of developing AD—though this is not very plausible given that the incidence of AD does not systematically increase with increased exposure.

For more information about these meta-analyses

Analysis of A. Ahlbom
In 2001, researcher Anders Ahlbom carried out several meta-analyses to determine if there was any link between exposure to EMFs and neurodegenerative diseases or psychological disorders. His analyses dealt with amyotrophic lateral sclerosis (seven studies), Alzheimer's disease (five studies), depression (six studies) and suicide (seven studies), and were carried out in a number of countries (United States, Canada, Great Britain, Sweden, Denmark and Finland). In the case of neurodegenerative diseases, the populations studied were mainly workers with occupational exposure to EMFs, whereas for depression and suicide, the population was made up of the general public as well as workers with occupational exposure.

The meta-analysis of seven studies dealing with amyotrophic lateral sclerosis (ALS, commonly called “Lou Gehrig's disease”) involved a total of 1,803 subjects with the disease. The findings revealed that working in an electric utility increased one's chances of developing ALS. The researcher concluded that exposure to EMFs could be one of several possible explanations. The meta-analysis of five studies on Alzheimer's disease (AD) looked at a total of 1,039 cases of people with the disease. According to the author, however, the results do not show any clear effect of EMFs on the incidence of AD.

With regard to depression and suicide, Anders Ahlbom believed that pooling the studies in question was not relevant because of the significant differences in their experimental protocols. As a result, he conducted a global analysis of the findings, and concluded that the association between exposure to EMFs and the risk of depression or suicide was rather tenuous.

Analysis of A. Garcia
A meta-analysis was carried out in 2008 by Ana M. Garcia to investigate the possible association between EMF exposure and Alzheimer’s disease (AD). The analysis covered a total of 14 studies (nine retrospective studies and five prospective studies) conducted in a number of countries (the United States, Sweden, Denmark, Finland and Turkey). The populations studied were mainly people with occupational exposure to EMFs.

The meta-analysis looked at a total of 2,748 cases of AD in the retrospective studies and 2,352 in the prospective studies. The results of the analysis of the retrospective as well as the prospective studies suggest that working in an electric utility increases the risk of developing AD. However, when the EMF exposures are stratified by class (≥ 0.2 µT, ≥ 0.3 µT, ≥ 0.5 µT, ≥ 1 µT), the risk of developing AD is not statistically significant.



As a whole, epidemiological studies have not found any link between exposure to magnetic fields and an increased risk of cardiovascular disease.

Most epidemiological studies have found that exposure to magnetic fields does not increase the number of deaths attributed to cardiovascular disease. While a few have shown the opposite, the reported increase in risk was not significant from a purely statistical point of view, and the resulting risk was low and quite comparable to that of the control group.

Other studies have looked at the risk of myocardial infarction and severe arrhythmia among workers with occupational exposure to magnetic fields. Although relatively few in number, such studies show that exposure to magnetic fields does not increase the risk of cardiovascular accident.

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