From Wikipedia, the free encyclopedia - View original article
Idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) is a descriptive term for symptoms purportedly caused by exposure to electromagnetic fields. Other terms for IEI-EMF include electromagnetic hypersensitivity (EHS), electrohypersensitivity, electro-sensitivity, and electrical sensitivity (ES).
Although the thermal effects of electromagnetic fields on the body are established, self-described sufferers of electromagnetic hypersensitivity report responding to non-ionizing electromagnetic fields (or electromagnetic radiation) at intensities well below the limits permitted by international radiation safety standards.
The reported symptoms of EHS include headache, fatigue, stress, sleep disturbances, skin symptoms like prickling, burning sensations and rashes, pain and ache in muscles and many other health problems. Whatever their cause, EHS symptoms are a real and sometimes disabling problem for the affected person.
The majority of provocation trials to date have found that self-described sufferers of electromagnetic hypersensitivity are unable to distinguish between exposure to real and fake electromagnetic fields, and it is not recognized as a medical condition by the medical or scientific communities. Since a systematic review in 2005 showing no convincing scientific evidence for it being caused by electromagnetic fields, several double-blind experiments have been published, each of which has suggested that people who report electromagnetic hypersensitivity are unable to detect the presence of electromagnetic fields and are as likely to report ill health following a sham exposure, as they are following exposure to genuine electromagnetic fields.
A 2001 survey found that people related their symptoms most frequently to mobile phone base stations (74%), followed by mobile phones (36%), cordless phones (29%) and power lines (27%). The survey was not designed to find any causal connection between electromagnetic field exposure and ill health.
A report from the UK Health Protection Agency said that self-described "electrical sensitivity" sufferers have symptoms that can be grouped into two broad categories: facial skin symptoms and more general, non-specific symptoms across a range of body systems. The facial skin symptoms and their attribution to visual display units was mostly a Nordic phenomenon. The report pointed out that it did not "imply the acceptance of a causal relationship between symptoms and attributed exposure".
Recently a smaller group of people in Europe as a whole and in the USA have reported general and severe symptoms such as headache, fatigue, tinnitus, dizziness, memory deficits, irregular heart beat, and whole-body skin symptoms. A 2005 Health Protection Agency report noted the overlap in many sufferers with other syndromes known as symptom-based conditions, FSS (functional somatic syndromes) and IEI (idiopathic environmental intolerance). Levitt proposed ties between electromagnetic fields and some of these 20th-century maladies, including chronic fatigue syndrome, Gulf War syndrome, and autism.
Figures from Carlsson et al. show that 1.9% of people report much annoyance from visual displays and fluorescent lighting. 2.4% report much or some annoyance with both any electrical factor and also chemicals or smells. A 1991 study by William J. Rea concluded that there is "strong evidence that electromagnetic field sensitivity exists".
Those reporting electromagnetic hypersensitivity will usually describe different levels of susceptibility to electric fields, magnetic fields and various frequencies of electromagnetic waves (including fluorescent and low-energy lights, and microwaves from mobile, cordless/portable phones), and Wifi with no consistency in the severity of symptoms between sufferers. Other surveys of electromagnetic hypersensitivity sufferers have not been able to find any consistent pattern to these symptoms. Instead symptoms reflecting almost every part of the body have been attributed to electromagnetic field exposure.
A minority of people who report electromagnetic hypersensitivity claim to be severely affected by it. For instance, one survey has estimated that approximately 10% of electromagnetic hypersensitivity sufferers in Sweden were on sick leave or have taken early retirement or a disability pension, compared to 5% of the general population, while a second survey has reported that of 3046 people who experienced 'annoyance' from electrical equipment, 340 (11%) reported 'much' annoyance. For those who report being severely affected, their symptoms can have a significant impact on their quality of life; with sufferers reporting physical, mental and social impairment and psychological distress.
The prevalence of claimed electromagnetic hypersensitivity has been estimated as being between a few cases per million to 5% of the population depending on the location and definition of the condition.
In 2002, a questionnaire survey of 2,072 people in California found that the prevalence of self-reported electromagnetic hypersensitivity within the sample group was 3% (95% CI 2.8–3.68%), with electromagnetic hypersensitivity being defined as "being allergic or very sensitive to getting near electrical appliances, computers, or power lines" (response rate 58.3%).
A similar questionnaire survey from the same year in Stockholm County (Sweden), found a 1.5% prevalence of self-reported electromagnetic hypersensitivity within the sample group, with electromagnetic hypersensitivity being defined as "hypersensitivity or allergy to electric or magnetic fields" (response rate 73%).
A 2004 survey in Switzerland found a 5% prevalence of claimed electromagnetic hypersensitivity in the sample group of 2,048.
In 2007, a UK survey aimed at a randomly selected group of 20,000 people found a prevalence of 4% for symptoms self-attributed to electromagnetic exposure.
A group of scientists also attempted to estimate the number of people reporting "subjective symptoms" from electromagnetic fields for the European Commission. In the words of a HPA review, they concluded that "the differences in prevalence were at least partly due to the differences in available information and media attention around electromagnetic hypersensitivity that exist in different countries. Similar views have been expressed by other commentators."
Following a study conducted in 2005, the World Health Organization(WHO) concluded that:
EHS is characterized by a variety of non-specific symptoms that differ from individual to individual. The symptoms are certainly real and can vary widely in their severity. Whatever its cause, EHS can be a disabling problem for the affected individual. EHS has no clear diagnostic criteria and there is no scientific basis to link EHS symptoms to EMF exposure. Further, EHS is not a medical diagnosis, nor is it clear that it represents a single medical problem.
Although individuals who report electromagnetic hypersensitivity believe that electromagnetic fields from common electrical devices trigger or exacerbate their symptoms, it has not been established that these fields play any role in the cause of these symptoms. Exposures are to intensity levels below those generally accepted to cause physiological effects, and the diverse physiological effects reported are not what would be expected from high intensity electromagnetic fields. Sufferers and their support groups are convinced of a causal relationship with electromagnetic fields, but presently the scientific literature does not support such a link. Some professionals consider electromagnetic hypersensitivity to be a physical condition with an unclear cause, while others suggest that some aspects may be psychological. Reviews have suggested that psychological mechanisms may play a role in causing or exacerbating EHS symptoms. Research has also shown neurophysiological differences between sensitive individuals and controls. This may reflect either a psychophysiological stress response to participating in the study or a more general imbalance in autonomic nervous system regulation.
In 2005, a systematic review looked at the results of 31 experiments testing the role of electromagnetic fields in causing ES. Each of these experiments exposed people who reported electromagnetic hypersensitivity to genuine and sham electromagnetic fields under single- or double-blind conditions. The review concluded that:
The symptoms described by 'electromagnetic hypersensitivity' sufferers can be severe and are sometimes disabling. However, it has proved difficult to show under blind conditions that exposure to electromagnetic fields can trigger these symptoms. This suggests that 'electromagnetic hypersensitivity' is unrelated to the presence of electromagnetic fields, although more research into this phenomenon is required.
Seven studies were found which did report an association, while 24 could not find any association with electromagnetic fields. However, of the seven positive studies, two could not be replicated even by the original authors, three had serious methodological shortcomings, and the final two presented contradictory results. Since then, several more double-blind experiments have been published, each of which has suggested that people who report electromagnetic hypersensitivity are unable to detect the presence of electromagnetic fields and are as likely to report ill health following a sham exposure, as they are following exposure to genuine electromagnetic fields.
One of the studies which Rubin et al. reviewed, known as the Essex study, received some criticism for its methodology and analysis, and the authors responded in full to these initial criticisms. The authors noted that their study says nothing about the long-term effects of exposure to electromagnetic fields, but those affected generally claimed to respond to the fields within a few minutes.
In January, 2010 Rubin et al. published a follow up to their original review which included 15 experiments done since the last original review, bringing the totals up to 46 double-blind experiments and 1175 individuals with claimed hypersensitivity. The study confirmed the results of the original, claiming "no robust evidence could be found" to support the hypothesis that electromagnetic exposure causes EHS. The review also found that the studies included did support the role of the nocebo effect in triggering acute symptoms in those with EHS.
In 2008, another systematic review reached the same conclusion as Rubin et al.
A 2005 report by the UK Health Protection Agency concluded that electromagnetic hypersensitivity needs to be considered in ways other than its etiology; that is, the suffering is real, even if the underlying cause is not thought to be related to electromagnetic fields. They also wrote that considering only whether electromagnetic radiation was a causative factor was not meeting the needs of sufferers, although continued research on etiology was essential.
In 2002, some controversy over the causal relationship was demonstrated by the Freiburger Appeal, a petition originated by the German environmental medical lobby group IGUMED, which stated that "we can see a clear temporal and spatial correlation between the appearance of [certain] disease and exposure to pulsed high-frequency microwave radiation", and demanding radical restrictions on mobile phone use. To address some of these concerns, and others, Hocking advised in a 2006 WHO proceedings that the test type and duration should be tailored to the individual, and that washout times are needed to prevent a carry-over effect of previous exposure. However, in 2005 the World Health Organization concluded that there is no known scientific basis for the belief that electromagnetic hypersensitivity is caused by exposure to electromagnetic fields.
Electromagnetic hypersensitivity is not currently an accepted diagnosis. At present there are no accepted research criteria other than 'self-reported symptoms', and for clinicians there is no case definition or clinical practice guideline. There is no specific test that can identify sufferers, as symptoms other than skin disorders tend to be subjective or non-specific. It is important firstly to exclude all other possible causes of the symptoms. Researchers and the WHO have stressed the need for a careful investigation. For some, complaints of electromagnetic hypersensitivity may mask organic or psychiatric illness and requires both a thorough medical evaluation to identify and treat any specific conditions that may be responsible for the symptoms, and a psychological evaluation to identify alternative psychiatric/psychological conditions that may be responsible or contribute to the symptoms.
A WHO factsheet also recommends an assessment of the workplace and home for factors that might contribute to the presented symptoms. These could include indoor air pollution, excessive noise, poor lighting (flickering light) or ergonomic factors. They also point out that "[s]ome studies suggest that certain physiological responses of [electromagnetic hypersensitivity] individuals tend to be outside the normal range. In particular, hyper reactivity in the central nervous system and imbalance in the autonomic nervous system need to be followed up in clinical investigations and the results for the individuals taken as input for possible treatment."
For individuals reporting electromagnetic hypersensitivity with long lasting symptoms and severe handicaps, treatment therapy should be directed principally at reducing symptoms and functional handicaps. This should be done in close co-operation with a qualified medical specialist to address the symptoms and a hygienist (to identify and, if necessary, control factors in the environment that have adverse health effects of relevance to the patient).
Those who feel they are sensitive to electromagnetic fields generally try to reduce their exposure to electromagnetic sources as much as is practical. Complete avoidance of electromagnetic fields presents major practical difficulties in modern society. Methods often employed by sufferers include: avoiding sources of exposure; disconnecting or removing electrical devices; shielding or screening of self or residence; medication; and complementary and alternative therapy.
The UK Health Protection Agency reviewed treatments for electromagnetic hypersensitivity, and success was reported with "neutralizing chemical dilution, antioxidant treatment, Cognitive Behavioural Therapy, Acupuncture and Shiatsu". It was noted that:
The studies reviewed suffer from a combination of the small numbers of subjects included and the potential variation both within and between study populations. Little information is given as to the attributed exposures of the subjects. These factors limit their general applicability outside the immediate study group. For those studies where detail was available, only two were placebo controlled [Acupunture and nutrition intervention].
It was also noted in the review that success may have more to do with offering a caring environment as opposed to a specific treatment.
A 2006 systematic review identified nine clinical trials testing different treatments for ES: four studies tested cognitive behavioural therapy, two tested visual display unit filters, one tested a device emitting 'shielding' electromagnetic fields, one tested acupuncture, and one tested daily intake of tablets containing vitamin C, vitamin E, and selenium. The authors of the review concluded that:
The evidence base concerning treatment options for electromagnetic hypersensitivity is limited and more research is needed before any definitive clinical recommendations can be made. However, the best evidence currently available suggests that cognitive behavioural therapy is effective for patients who report being hypersensitive to weak electromagnetic fields.
In 2004 the World Health Organization (WHO) conducted a workshop on electromagnetic hypersensitivity. The aim of the conference was to review the current state of knowledge and opinions of the conference participants and propose ways forward on this issue. The meeting was conducted by the WHO International EMF Project as part of the scientific review process to determine biological and health effects from exposure to EMF. The purpose of these workshops is to bring together expert scientists so that established health effects and gaps in knowledge requiring further research can be identified. EHS has been a particularly contentious issue for a number of years.