Dear Friends – Because the issue has been raised as to the effects of CORONA FIELDS that are created by high voltage devices and power lines, I am posting the information below for posterity’s sake. The information has been wiped from the internet but can still be seen by plugging in this link at http://web.archive.org.
Original Source of this Information Can be Seen Here
Current evidence on health
There are some effects that EMFs have, usually at relatively high levels, where there is little doubt about the effects – they are regarded as established. We have a whole section on these effects: induced currents, microshocks, effects on equipment, etc.
In this section we address the possibility of effects at lower levels – effects which are not established, but where there is some evidence suggesting the possibility of effects.
Childhood leukaemia
Of all the possible effects of EMFs, the evidence is strongest for childhood leukaemia and we summarise the evidence here.
Other human health effects
These evidence for EMFs causing these is weaker and we summarise it here: other cancers, neurodegenerative disorders, suicide and depression, and many others.
What the experts say
Many review bodies have surveyed this evidence and reported on it, and we summarise all their conclusions.
Electric fields and ions
There is a whole set of theories that power lines may affect health not through the magnetic fields they produce but through electric fields and ions – see the evidence here.
Comparing EMFs to other issues
Here we compare the evidence for health effects from EMFs to smoking, coffee, etc, and provide some information on comparative risks.
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Electric fields and ions
The suggestions
In 1996 and in 1999, the Bristol University Human Radiation Effects Group published papers suggesting that the electric fields from high-voltage overhead power lines might influence the behaviour of airborne particles in such a way as to be harmful to human health. The main example given was radon daughter products.
The suggestions made were:
- That electric fields make harmful particles from the atmosphere more likely to stick to the skin
- That electric fields increase the concentration of harmful particles in the atmosphere near the source of the field
- That power lines produce “corona ions” which make particles in the atmosphere more likely to stick in the lungs
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Neurodegenerative disorders
The main neurodegenerative disorders are Alzheimer’s disease, Parkinson’s disease, and Amyotrophic Lateral Sclerosis (ALS, known in the USA as Lou Gehrig’s disease). For Alzheimer’s disease, see also a compilation of the abstracts of the epidemiological studies dealing with this and information on a new study in 2008 by Huss et al further down this page.
Conclusions of review bodies on neurodegenrative disorders generally
View of NRPB
In November 2001 the NRPB’s Advisory Group published a Report on electromagnetic fields and neurodegenerative disease. The conclusion was:
There is no good ground for thinking that exposure to extremely low frequency electromagnetic fields can cause Parkinson’s disease and only very weak evidence to suggest it could cause Alzheimer’s disease. The evidence that people employed in electrical occupations have an increased risk of developing amyotrophic lateral sclerosis is substantially stronger, but this could be because they run an increased risk of having an electric shock rather than any effect of long-term exposure to the fields per se. More on NRPB
In its new advice on exposure guidelines in 2004, the NRPB stated:
Studies of occupational exposure to ELF EMFs do not provide strong evidence of associations with neurodegenerative diseases. The only possible exception concerns people employed in electrical occupations who appear to have an increased risk of developing amyotrophic lateral sclerosis; however, this may be due to effects of electric shocks rather than any effect of long-term exposure to the fields per se. More on NRPB
View of ICNIRP
A major review published by ICNIRP in 2002 concluded:
For reasons discussed in the preceding sections, the ALS [amyotrophic Lateral sclerosis] results are intriguing and point toward a possible risk increase in subjects with EMF exposure. However, confirmatory studies are needed, as is an appropriate consideration of confounding, for example, from electric shocks, as a conceivable explanation. As for AD [Alzheimer’s disease], it appears the excess risk is constrained to studies with weaker designs; thus support for the hypothesis of a link between EMF and AD is weak. More on ICNIRP
View of SCENIHR
SCENIHR is the European Commission’s Scientific Committee on Emerging and Newly Identified Health Risks. In their opinion on EMFs in 2007 they stated:
For several of the other outcomes the support was never strong. Nevertheless, several neurodegenerative diseases are still considered worthy of study in this respect, and this refers particularly to ALS (amyotrophic lateral sclerosis) and Alzheimer disease.
In a 2009 update they said:
New epidemiological studies indicate a possible increase in Alzheimer’s disease arising from exposure to ELF. Further epidemiological and laboratory investigations of this observation are needed.
In their latest 2015 update they say in the main text:
Only few new studies have been published since the previous Opinion. Although the new studies in some cases have methodological weaknesses, they do not provide support for the previous conclusion that ELF MF exposure increases the risk for Alzheimer’s disease.
Epidemiological studies do not provide convincing evidence of an increased risk of neurodegenerative diseases, including dementia, related to power frequency MF exposure.
View of WHO
The WHO Environmental Helath Criteria Monograph published in 2007 concluded:
It has been hypothesized that exposure to ELF fields is associated with several neurodegenerative diseases. For Parkinson’s disease and multiple sclerosis the number of studies has been small and there is no evidence for an association with these diseases. For Alzheimer’s disease and amyotrophic lateral sclerosis (ALS) more studies have been published. Some of these reports suggest that people employed in electrical occupations might have an increased risk of ALS. So far, no biological mechanism has been established which can explain this association, although it could have arisen because of confounders related to electrical occupations, such as electric shocks. Overall, the evidence for the association between ELF exposure and ALS is considered to be inadequate.
The few studies investigating the association between ELF exposure and Alzheimer’s disease are inconsistent. However, the higher quality studies that focused on Alzheimer morbidity rather than mortality do not indicate an association. Altogether, the evidence for an association between ELF exposure and Alzheimer’s disease is inadequate.
The Huss et al study from Switzerland
We give here more information on one important study that was published in the American Journal of Epidemiology in 2008, of neurodegenerative disorders in Switzerland in relation to proximity to power lines. See the press release by the university concerned.
It reports an association between living within 50 m of a power line (particularly for longer periods) and Alzheimer’s disease but not ALS, Parkinson’s disease or multiple sclerosis.
Results for Alzheimer’s disease
The relative risks for subjects living at various distances from the power lines are shown here (for the subjects who had lived there at least 15 years):
And the relative risks for various durations of residence are shown here, for subjects living within 50 m:
Abstract
Residence Near Power Lines and Mortality From Neurodegenerative Diseases: Longitudinal Study of the Swiss Population.
Huss A, Spoerri A, Egger M, Röösli M; for the Swiss National Cohort Study.The relation between residential magnetic field exposure from power lines and mortality from neurodegenerative conditions was analyzed among 4.7 million persons of the Swiss National Cohort (linking mortality and census data), covering the period 2000-2005. Cox proportional hazard models were used to analyze the relation of living in the proximity of 220-380 kV power lines and the risk of death from neurodegenerative diseases, with adjustment for a range of potential confounders. Overall, the adjusted hazard ratio for Alzheimer’s disease in persons living within 50 m of a 220-380 kV power line was 1.24 (95% confidence interval (CI): 0.80, 1.92) compared with persons who lived at a distance of 600 m or more. There was a dose-response relation with respect to years of residence in the immediate vicinity of power lines and Alzheimer’s disease: Persons living at least 5 years within 50 m had an adjusted hazard ratio of 1.51 (95% CI: 0.91, 2.51), increasing to 1.78 (95% CI: 1.07, 2.96) with at least 10 years and to 2.00 (95% CI: 1.21, 3.33) with at least 15 years. The pattern was similar for senile dementia. There was little evidence for an increased risk of amyotrophic lateral sclerosis, Parkinson’s disease, or multiple sclerosis.
Replication
Frei et al published a study from Denmark, designed to test the Huss et al finding, which failed to replicate the finding. This was one of the studies that led SCENIHR to conclude in their 2015 Opinion that
Only few new studies have been published since the previous Opinion. Although the new studies in some cases have methodological weaknesses, they do not provide support for the previous conclusion that ELF MF exposure increases the risk for Alzheimer’s disease.
Am J Epidemiol. 2013 May 1;177(9):970-8.
Residential distance to high-voltage power lines and risk of neurodegenerative diseases: a Danish population-based case-control study.
Frei P, Poulsen AH, Mezei G, Pedersen C, Cronberg Salem L, Johansen C, Röösli M, Schüz J.
The aim of this study was to investigate the possible association between residential distance to high-voltage power lines and neurodegenerative diseases, especially Alzheimer’s disease. A Swiss study previously found increased risk of Alzheimer’s disease for people living within 50 m of a power line. A register-based case-control study including all patients diagnosed with neurodegenerative diseases during the years 1994-2010 was conducted among the entire adult population of Denmark. Using conditional logistic regression models, hazard ratios for ever living close to a power line in the time period 5-20 years before diagnosis were computed. The risks for developing dementia, Parkinson’s disease, multiple sclerosis, and motor neuron disease were not increased in persons living within close vicinity of a power line. The risk of Alzheimer’s disease was not increased for ever living within 50 m of a power line (hazard ratio = 1.04, 95% confidence interval: 0.69, 1.56). No dose-response according to number of years of living within 50 m of a power line was observed, but there were weak indications of an increased risk for persons diagnosed by the age of 75 years. Overall, there was little support for an association between neurodegenerative disease and living close to power lines.
Multiple Sclerosis
Multiple sclerosis has not been looked at as much as the other neurodegenrative disorders. We are aware of just one paper which concludes it found “no support” for an association with EMFs.
Neurology. 1999 Apr 12;52(6):1279-82.
Multiple sclerosis among utility workers
Johansen C, Koch-Henriksen N, Rasmussen S, Olsen JH.
Institute of Cancer Epidemiology, The Danish Cancer Society, Copenhagen. christof@cancer.dk
The incidence of MS was assessed in a nationwide cohort study of 31,990 employees of Danish utility companies between 1900 and 1993. Overall, 32 cases of MS were diagnosed, as compared with 23.7 expected from national incidence rates, to yield a standardized incidence ratio of 1.35 (95% confidence interval, 0.92 to 1.91). We found no support for the hypothesis of an association between occupational exposure to electromagnetic fields and the risk of MS.
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Suicide and depression
View of ICNIRP
A major review published by ICNIRP in 2001 concluded:
“When assessing the overall literature on EMF and suicide, it is necessary to consider the relative weights of the available studies together with their results. In doing so the original study must be given a relatively light weight in relation to later studies because of methodological limitations. Nevertheless, the latest study also suggests that an excess risk may indeed exist.
The literature on depressive symptoms and EMF is difficult to interpret because the findings are not consistent. This complexity cannot easily be resolved by suggesting that one type of result can be confined to a group of studies with methodological problems or some other limitation.” More on ICNIRP
View of NRPB
In its new advice on exposure guidelines in 2004, NRPB stated:
“Studies of suicide and depressive illness have given inconsistent results in relation to ELF EMF exposure…” More on NRPB
The key papers
We give here the abstracts from the key epidemiological papers on suicide and depression.
Suicide and depression abstracts
Epidemiological studies of suicide and depression and magnetic fields
We provide here the abstracts for the major epidemiological studies of magnetic fields or power lines and suicide and depression. See also a summary of the evidence.
| Baris and Armstrong 1990 | Suicide, occupational |
| Baris, Armstrong, Deadman and Theriault 1996 | Suicide, occupational |
| Beale, Pearce, Conroy, Henning and Murrell 1997 | Psychological effects, power lines |
| Dowson, Lewith, Campbell, Mullee and Brewster 1988 | Headaches and depression, power lines |
| McDowall 1986 | Mortality (including suicide), power lines |
| McMahan, Ericson and Meyer 1994 | Depression, power lines |
| Perry, Pearl and Binns 1989 | Depression, residential magnetic field |
| Perry, Reichmanis, Marino and Becker 1981 | Suicide, residential magnetic field |
| Poole, Kavet, Funch, Donelan, Charry and Dreyer 1993 | Headaches and depression power lines |
| Reichmanis, Perry, Marino and Becker 1979 | Suicide, power lines |
| Savitz, Boyle and Holmgreen 1994 | Depression, occupation |
| van Wijngaarden, Savitz, Kleckner, Cai and Loomis 2000 | Suicide, occupation |
| van Wijngaarden, Savitz, Kleckner, Cai and Loomis 2000 | Suicide, occupation |
| Verkasalo, Kaprio, Varjonen, Romanov, Heikkila and Koskenvuo 1997 | Depression, power lines |
| Zyss, Dobrowolski and Krawczyk 1997 | Depression, power lines |
| Zyss 1999 | Depression, power lines |
Suicide among electric utility workers in England and Wales.Baris D, Armstrong B.
[letter – no abstract]
Occup Environ Med 1996 Jan;53(1):17-24
A case cohort study of suicide in relation to exposure to electric and magnetic fields among electrical utility workers.
Baris D, Armstrong BG, Deadman J, Theriault G.
Department of Occupational Health, Faculty of Medicine, McGill University, Montreal, Canada.
OBJECTIVES–This case cohort study examines whether there is an association between exposure to electric and magnetic fields and suicide in a population of 21,744 male electrical utility workers from the Canadian Province of Quebec. METHODS–49 deaths from suicide were identified between 1970 and 1988 and a subcohort was selected comprising a 1% random sample from this cohort as a basis for risk estimation. Cumulative and current exposures to electric fields, magnetic fields, and pulsed electromagnetic fields (as recorded by the POSITRON meter) were estimated for the subcohort and cases through a job exposure matrix. Two versions of each of these six indices were calculated, one based on the arithmetic mean (AM), and one on the geometric mean (GM) of field strengths. RESULTS–For cumulative exposure, rate ratios (RR) for all three fields showed mostly small non-significant increases in the medium and high exposure groups. The most increased risk was found in the medium exposure group for the GM of the electric field (RR = 2.76, 95% CI 1.15-6.62). The results did not differ after adjustment for socioeconomic state, alcohol use, marital state, and mental disorders. There was a little evidence for an association of risk with exposure immediately before the suicide. CONCLUSION–Some evidence for an association between suicide and cumulative exposure to the GM of the electric fields was found. This specific index was not initially identified as the most relevant index, but rather emerged afterwards as showing the most positive association with suicide among the 10 indices studied. Thus the evidence from this study for a causal association between exposure to electric fields and suicide is weak. Small sample size (deaths from suicide) and inability to control for all potential confounding factors were the main limitations of this study.
Bioelectromagnetics 1997;18(8):584-94
Psychological effects of chronic exposure to 50 Hz magnetic fields in humans living near extra-high-voltage transmission lines.
Beale IL, Pearce NE, Conroy DM, Henning MA, Murrell KA.
Department of Psychology, University of Auckland, New Zealand.
The validity of several published investigations of the possibility that residential exposures to 50 Hz or 60 Hz electromagnetic fields might cause adverse psychological effects, such as suicide and depression, may have been limited by inadequate controlling for confounders or inadequate measurement of exposures. We investigated the relationships between magnetic field exposure and psychological and mental health variables while controlling for potential confounders and careful characterising individual magnetic field exposures. Five-hundred-and-forty adults living near transmission lines completed neuropsychological tests in major domains of memory and attentional functioning, mental health rating scales and other questionnaires. Magnetic field measurements were taken in each room occupied for at least one hour per day to provide an estimate of total-time-integrated exposure. The data were subjected to joint multivariate multiple regression analysis to test for a linear relation between field exposure and dependent variables, while controlling for effects of possible confounders. Performance on most memory and attention measures was unrelated to exposure, but significant linear dose-response relationships were found between exposure and some psychological and mental health variables. In particular, higher time-integrated exposure was associated with poorer coding-test performance and more adverse psychiatric symptomatology. These associations were found to be independent of participants’ beliefs about effects of electromagnetic fields.
Practitioner 1988 Apr 22;232(1447):435-6
Overhead high-voltage cables and recurrent headache and depressions.
Dowson DI, Lewith GT, Campbell M, Mullee MA, Brewster LA.
[No abstract in PubMed]
Br J Cancer 1986 Feb;53(2):271-9
Mortality of persons resident in the vicinity of electricity transmission facilities.
McDowall ME.
Several studies have raised the possibility that exposure to electrical and/or magnetic fields may be injurious to health in particular by the promotion or initiation of cancer. To investigate whether the electricity transmission system presents a long term hazard to public health, the mortality of nearly 8,000 persons, identified as living in the vicinity of electrical transmission facilities at the time of the 1971 Population Census, has been followed to the end of 1983. All identified transmission installations within pre-defined areas were included in the study with the result that the greater part of the study group were believed to be resident near relatively low voltage sub-stations. Overall mortality was lower than expected and no evidence of major health hazards emerged. The only statistically significant excess mortality was for lung cancer (in women overall, and in persons living closest to the installations); this result is difficult to interpret in the absence of smoking data, and is not supported by other evidence but does not appear to be due to the social class distribution of the study group. The study did not support previously reported associations of exposure to electro-magnetic fields with acute myeloid leukaemia, other lymphatic cancers and suicide.
Am J Epidemiol 1994 Jan 1;139(1):58-63
Depressive symptomatology in women and residential proximity to high-voltage transmission lines.
McMahan S, Ericson J, Meyer J.
Department of Environmental Health, School of Social Ecology, University of California, Irvine 92717.
A number of epidemiologic studies indicate an association between depression and proximity to high-voltage transmission lines. These studies have been criticized, however, for using surrogate measures of electromagnetic fields and unstandardized measures of depression. In an effort to overcome these limitations, the authors administered the Center for Epidemiological Studies Depression scale (CES-D) in 1992 to 152 women in Orange County, California, who lived either adjacent to a transmission line or one block away. The results indicated that the average magnetic field level is 4.86 mG at the front door of homes adjacent to transmission lines and 0.68 mG at the front door of homes one block away. There was no significant difference in CES-D scores between the groups when demographic variables were controlled for. The homogeneity of the study population may limit the generalizability of findings.
Public Health 1989 May;103(3):177-80
Power frequency magnetic field; depressive illness and myocardial infarction.
Perry S, Pearl L, Binns R.
Surveys were made to determine whether susceptibility to depressive illness and to myocardial infarction of people living in Wolverhampton was related to the intensity of 50 Hz magnetic field outside their homes. Comparing case with control addresses it was found that the field strength was significantly higher for depressive illness (P = 0.033) but not for myocardial infarction.
Health Phys 1981 Aug;41(2):267-77
Environmental power-frequency magnetic fields and suicide.
Perry FS, Reichmanis M, Marino AA, Becker RO.
[no abstract in PubMed]
Am J Epidemiol 1993 Feb 1;137(3):318-30
Depressive symptoms and headaches in relation to proximity of residence to an alternating-current transmission line right-of-way.
Poole C, Kavet R, Funch DP, Donelan K, Charry JM, Dreyer NA.
Epidemiology Resources Inc., Newton Lower Falls, MA 02162.
Electric power transmission lines have become objects of public controversy. Hypotheses have linked neurobehavioral effects to the electric and magnetic fields that these lines produce. The authors conducted a telephone interview survey in November 1987 to assess the prevalence of depressive symptoms and headache in relation to proximity of residence to an alternating-current transmission line in the United States. Proximity to the line, defined as residing on a property abutting the right-of-way or being able to see the towers from one’s house or yard, was positively associated with a measure of depressive symptoms. The association was not explained by demographic variables associated with depression or by attitudes about power lines or other environmental issues. The estimated prevalence odds ratio was 2.8 (95% confidence interval (CI) 1.6-5.1). The estimate did not change appreciably when the definitions of depressive symptoms or of proximity to the line were altered. Nonmigraine headaches had a weaker association with proximity to the line (odds ratio = 1.5, 95% CI 0.76-2.8), and self-reported migraine headaches exhibited no association (odds ratio = 0.99, 95% CI 0.29-3.4). Additional studies of psychological and behavioral measures should be conducted in relation to electric and magnetic fields, with a strong emphasis on improved exposure assessment.
Physiol Chem Phys 1979;11(5):395-403
Relation between suicide and the electromagnetic field of overhead power lines.
Reichmanis M, Perry FS, Marino AA, Becker RO.
Laboratory studies have shown that electromagnetic fields similar to those from high-voltage transmission lines can produce biological effects. Surveys of the actual effects of such lines on exposed individuals usually have been hampered by complicating factors tending to blur the data. By means of a new approach, however, correlation has been established between the presence of transmission-line fields and the occurrence of suicides in part of the Midlands of England.
Am J Ind Med 1994 Feb;25(2):165-76
Prevalence of depression among electrical workers.
Savitz DA, Boyle CA, Holmgreen P.
Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill 27599-7400.
To address the possible association between electric and magnetic field exposure and depression, we analyzed data from the Vietnam Experience Study. In order to compare the risk of diagnosed depression, depressive symptoms, and elevations in personality scales indicative of depression, we classified employed participants as electrical workers (N = 183) and nonelectrical workers (N = 3,861) and compared their scores on the Diagnostic Interview Survey (DIS) and the Minnesota Multiphasic Personality Inventory (MMPI). Electrical workers in the aggregate showed little evidence of increased risk, with the possible exception of an increase in elevated MMPI depression scores among short-term workers. Data on electricians yielded indications of increased risk for several markers of depression. Despite the limited number of electrical workers, uncertainty regarding exposure, and our inability to address other workplace exposures, these results suggest that electrical workers in general are not at increased risk for depression. However, our results encourage further evaluation of depression among electricians.
Occup Environ Med 2000 Apr;57(4):258-63
Exposure to electromagnetic fields and suicide among electric utility workers: a nested case-control study.
van Wijngaarden E, Savitz DA, Kleckner RC, Cai J, Loomis D.
Department of Epidemiology, School of Public Health, The University of North Carolina, Chapel Hill, NC, USA.
OBJECTIVES: This nested case-control study examines mortality from suicide in relation to estimated exposure to extremely low frequency electromagnetic fields (EMFs) in a cohort of 138,905 male electric utility workers. METHODS: Case-control sampling included 536 deaths from suicide and 5348 eligible controls. Exposure was classified based on work in the most common jobs with increased exposure to magnetic fields and indices of cumulative exposure to magnetic fields based on a measurement survey. RESULTS: Suicide mortality was increased relative to work in exposed jobs and with indices of exposure to magnetic fields. Increased odds ratios (ORs) were found for years of employment as an electrician (OR 2.18; 95% confidence interval (95% CI) 1.25 to 3.80) or lineman (OR 1.59; 95% CI 1.18 to 2.14), whereas a decreased OR was found for power plant operators (OR 0.67; 95% CI 0.33 to 1.40). A dose response gradient with exposure to magnetic fields was found for exposure in the previous year, with a mortality OR of 1.70 (95% CI 1.00 to 2.90) in the highest exposure category. Stronger associations, with ORs in the range of 2.12-3.62, were found for men <50 years of age. CONCLUSION: These data provide evidence for an association between occupational electromagnetic fields and suicide that warrants further evaluation. A plausible mechanism related to melatonin and depression provides a direction for additional laboratory research as well as epidemiological evaluation.
West J Med 2000 Aug;173(2):94-100
Exposure to electromagnetic fields and suicide among electric utility workers: a nested case-control study.
van Wijngaarden E, Savitz DA, Kleckner RC, Cai J, Loomis D.
Department of Epidemiology, University of North Carolina, School of Public Health CB 7400, Chapel Hill, NC 27599-7400, USA.
OBJECTIVE: To examine mortality from suicide in relation to estimated exposure to extremely low-frequency electromagnetic fields in a cohort of 138,905 male electric utility workers. METHODS: Case-control sampling, which included 536 deaths from suicide and 5, 348 eligible controls. Exposure was classified based on work in the most common jobs with increased exposure to magnetic fields and indices of cumulative exposure to magnetic fields based on a measurement survey. RESULTS: Suicide mortality was increased relative to work in exposed jobs and with indices of exposure to magnetic fields. Increased odds ratios (ORs) were found for years of employment as an electrician (OR, 2.18; 95% confidence interval [CI], 1.25-3.80) or line worker (OR, 1.59; 95% CI, 1.18-2.14), whereas a decreased OR was found for power plant operators (OR, 0.67; 95% CI, 0.33-1.40). A dose-response gradient with exposure to magnetic fields was found for exposure in the previous year, with a mortality OR of 1.70 (95% CI, 1.00-2.90) in the highest exposure category. Stronger associations, with ORs in the range of 2.12 to 3.62, were found for men younger than 50 years. CONCLUSIONS: These data provide evidence for an association between occupational electromagnetic fields and suicide that warrants further evaluation. A plausible mechanism related to melatonin and depression provides a direction for additional laboratory research and epidemiologic evaluation.
Am J Epidemiol 1997 Dec 15;146(12):1037-45
Magnetic fields of transmission lines and depression.
Verkasalo PK, Kaprio J, Varjonen J, Romanov K, Heikkila K, Koskenvuo M.
Department of Public Health, University of Helsinki, Finland.
Electromagnetic fields have been suggested to contribute to the risk of depression by causing pineal dysfunction. Some epidemiologic studies have supported this possibility but have generally reported crude methods of exposure assessment and nonsystematic evaluation of depression. Using two available nationwide data sets, the authors identified from the Finnish Twin Cohort Study 12,063 persons who had answered the 21-item Beck Depression Inventory of self-rated depressive symptoms in 1990. The personal 20-year histories of exposure (i.e., distance and calculated annual average magnetic fields) before 1990 to overhead 110- to 400-kv power lines were obtained from the Finnish Transmission Line Cohort Study. The adjusted mean Beck Depression Inventory scores did not differ by exposure, providing some assurance that proximity to high-voltage transmission lines is not associated with changes within the common range of depressive symptoms. However, the risk of severe depression was increased 4.7-fold (95% confidence interval 1.70-13.3) among subjects living within 100 m of a high-voltage power line. This finding was based on small numbers. The authors recommend that attempts be made to strive for a better understanding of the exposure characteristics in relation to the onset and course of depression.
Med Pr 1997;48(5):495-505
Neurotic disturbances, depression and anxiety disorders in the population living in the vicinity of overhead high-voltage transmission line 400 kV. Epidemiological pilot study [Article in Polish]
Zyss T, Dobrowolski JW, Krawczyk K.
Katedry Psychiatrii, Collegium Medicum Uniwersytetu Jagiellonskiego w Krakowie.
Numerous reports suggest a relationship between the increased incidence of depressive and neurotic symptoms in humans and the exposure to extremely low frequency electromagnetic field (EMF) at the place of residence. Our study was conducted in one of the Cracow suburbs with low socio-economic status, adjacent to an easement containing two 400 kV high-voltage transmission lines (distance up to 50 m from the line). The population investigated comprised 70 persons (35 males and 35 females). This group was exposed to EMF from 1986. A control group (n = 37), non-exposed to EMF, was also tested. The EMF intensity was measured by special devices. The following assessments instruments were used: Anamnestic Data Questionnaire, Neurotic Symptoms Questionnaire “O” Spielberger Self-Rating Questionnaire, and Beck-Self-Rating Scale. The measurements of the electric field levels taken at the front walls of investigated buildings averaged much higher than normal values of safety exposure. Our investigation showed the increased psychopathological values in all clinical tests. The difference between the group exposed to EMF and the control population was statistically significant. The results of our study did not support a possible cause-and-effect relationship between EMF and psychopathology observed. Some other factors (noise) can be responsible for the data obtained. The hypothesis that EMF produced by external electric power lines may enhance the occurrence of neurotic symptoms and depression, requires further clinical and experimental investigations.
Psychiatr Pol 1999 Jul-Aug;33(4):535-51
Epidemiological studies on neurotic disturbances, anxiety and depression disorders in a population living near an overhead high voltage transmission line (400 kV) [Article in Polish]
Zyss T.
Katedry Psychiatrii Collegium Medicum UJ w Krakowie. mzzyss@cyf-kr.edu.pl
Epidemiological studies indicate an increased incidence of depression and neurotic disorders in persons long exposed to influence of electromagnetic fields. The examinations covered a selected population of several suburban neighborhoods of Cracow living not farther than 50 m from a 400 kV high-voltage transmission line. A group of 70 persons (35 men and 35 women) living near the transmission line for longer than 10 years was examined. A control group consisted of 37 persons not subjected to an influence of similar transmission line. Instruments used in the examination included: Symptom Checklist “0”, Spielberge’s Self-assessment Questionnaire and Beck’s Inventory. Also, a modified life-history questionnaire was applied. In the examined households we found significantly increased values of intensity of the electric component (by the so-called “ecological” Swedish norms). The population resident in the closest neighborhood of the examined transmission-line manifested high level of psychopathology, significantly different than that in the control group. However, the obtained results do not allow us to state univocally whether the observed psychopathology remains in causal nexus with the exposure to electromagnetic field. Other factors, like noise, may also be responsible for these results. The hypothesis that electromagnetic fields generated by high-voltage transmission lines may evoke depressive disorders and depression requires further clinical and experimental studies.
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Childhood leukaemia
Around 20 epidemiological studies have now been performed looking just at a possible link between childhood leukaemia and EMFs. Scientific papers have an abstract and you can read the abstracts of the more important epidemiological studies here. Some of those studies found no association with magnetic fields, but most have found associations. Overall there is clearly a statistical association within the studies that have been performed between unusually high magnetic fields and childhood leukaemia.
By contrast, the evidence from the laboratory is that low level EMFs of the type experienced by the public do not seem to have the harmful effects that have been claimed, and we have not identified a mechanism:
Overall, the evidence is strong enough for the official classification (by IARC and WHO) to be “possibly” a cause of cancer, the middle of 5 categories more on the IARC categories.
Most review groups agree the evidence for EMFs causing diseases other than childhood leukaemia is weaker – WHO described it as “much weaker”.
Summarising the epidemiological evidence
There have been at least twenty epidemiological studies of childhood leukaemia. See the abstracts of the dozen or so most important studies on childhood leukaemia.
We have more details on some of the important studies:
- the UKCCS, a UK study that measured fields in the home
- the CCRG or “Draper” study, a UK study that looked at proximity to power lines and calculated fields from those power lines
- Geocap, a French study
These individual studies of childhood leukaemia are best summed up in the various pooled analyses, notably the Ahlbom study from 2000 and the Kheifets et al follow-up in 2010. Pooled analyses (as the name suggests) pool the results from all the individual studies to calculate a single overall result. This graph is a summary of the results from the 2000 Ahlbom pooled analysis:
This suggests little or no evidence of risk in the intermediate exposure categories, but a doubling of risk – a relative risk of 2 – for fields in the home above 0.4 µT.
See more detail on pooled analyses – alternative interpretations of this result, and the update to it in 2010.
Two important UK studies
The Childhood Cancer Research Group Study
This study published in 2005 (also known as the “Draper” study) is a collaboration between the CCRG at the University of Oxford and National Grid. It looks at whether children who get cancer were born near power lines or not. It found:
“While few children in England and Wales live close to high voltage power lines at birth, there is a slight tendency for the birth addresses of children with leukaemia to be closer to these lines than those of matched controls.”
The strange thing about this result is that it seems to extend much further from power lines – up to 600 m – than magnetic fields do. The authors say:
“…our results do not seem to be compatible with the existing data on the relation between magnetic fields and risk.”
and
“We have no satisfactory explanation for our results in terms of causation by magnetic fields or association with other factors.”
more detail on the CCRG study.
The United Kingdom Childhood Cancer Study
The biggest of all the epidemiological studies of EMFs and childhood cancer until the Draper study was conducted during the 1990s, called the United Kingdom Childhood Cancer Study (UKCCS). It looked at a number of suggested causes of childhood cancer including EMFs. Its particularly large study population – over 2000 cases of cancer in total, three times larger than the next largest study before it – makes it very powerful. It was conducted by an eminent group of scientists, led by Sir Richard Doll, who first identified the link between smoking and lung cancer.
The UKCCS was designed to look at every case of childhood leukaemia occurring in the UK over roughly a four-year period. It is hard to envisage a study better able to give comprehensive answers about childhood cancer in the UK, and if a link with EMFs exists, this study was expected to find it.
In December 1999, the UKCCS published its report on exposure to magnetic fields and concluded:“This study provides no evidence that exposure to magnetic fields associated with the electricity supply in the UK increases risk for childhood leukaemia, cancers of the nervous system, or any other childhood cancer.”
Nonetheless, even though the UKCCS on its own provides “no evidence” of a risk, the pooled analysis, which included the UKCCS, still found a statistical association.
more detail on the UKCCS including further publications on electric fields and proximity to power lines.
What could the other explanations for the evidence be?
Associations from epidemiological studies on their own do not establish causation (More on what epidemiology can or cannot show). The associations could be caused by two other things:
- Bias in the study. If the children chosen to take part in the study were not properly representative of the population as a whole, the association that was found in the study might not exist in the rest of the population. We know that this problem (often called “control selection bias”) exists in most of the studies; what we don’t yet know is exactly how significant it is. More on bias.
- Other factors which were not properly controlled for. Something which does actually cause childhood cancer might be associated with magnetic fields so that children are exposed to both at once. Then the association that the study found would be caused by the other factor and not by EMFs. This is known as a “confounding factor”. We list here some of the other factors which vary with magnetic fields.
Some specific alternative explanations that have been looked at:
- the corona ion hypothesis – that effects near high-voltage power lines are caused not by the magnetic field but by the corona ions emitted by those lines
- the contact current hypothesis – that effects might be caused by contact voltages in homes producing effects in bone marrow