電磁場與公共衛生

附註︰另一份英國HPA的相關文件(網址如下)請參考。

http://www.hpa.org.uk/radiation/publications/hpa_rpd_reports/2005/hpa_rpd_010.pdf

世界衛生組織 296號文件發表日期：2005年12月

電磁場與公共衛生

電磁場過敏症

隨著社會工業化和技術革命演進，電磁場來源的數量和多樣性方面已急遽增加。這些來源包括電腦、行動電話及其基地台等設備。雖然這些裝置使我們的生活更豐富、更安全和更便利，但是伴隨它們而來的，是對其所可能產生電磁場健康風險之的關切。

~~近期許多個案指出~~近年來有些人，他們認為他們的許多~~個人的多種~~健康問題與電磁場暴露有關。一有些個案指出，在~~盡可能~~儘可能避免這些磁場暴露時，~~會有較輕度的~~過敏反應會減輕，~~其他人則會~~另外有些個案則受到嚴重影響，以致必須停止工作或和改變其全部生活方式。這種~~被認為~~對電磁場產生敏感反應的情形，一般稱為“電磁場過敏症”。

本報告描述關於這種狀況的已知知識，並提供資訊以幫助有此類症狀的人。提供的資訊以世衛組織電磁場過敏症工作坊（捷克布拉格, 2004年）、電磁場與非特異性健康症狀國際會議（COST244bis，1998年）、歐盟報告（Bergqvist和Vogel, 1997年)以及近期文獻回顧為基礎。

什麼是電磁場過敏症?

電磁場過敏症的表徵是多種重非特異性症狀，可歸因於電磁場暴露而使個人遭受痛苦。這些常見的症狀包括皮膚症狀（發紅、刺痛感和燒灼感）以及神經衰弱和其他不適症狀（疲乏、勞累、不專心、眩暈、噁心、心悸和消化障礙）。這些症狀候的聚集並非任何已知症狀候群的一部分。

電磁場過敏症很像多種化學物質過敏症—另一種與化學物質低量環境暴露有關的病症。以上兩者的特點均為一系列非特異性症狀，缺乏明顯的毒理學或生理學基礎或獨立的驗證。對環境因素過敏的狀況一般稱為突發性環境不相容（Idiopathic Environmental Intolerance (IEI)），這個新名辭源自世衛組織國際化學品安全規劃1996年在柏林舉辦的工作坊。突發性環境不相容是一個描述詞，沒有涉及任何化學病因學、免疫過敏症或電磁場易感性的含意。突發性環境不相容包括許多普遍對人們產生不適感覺，在醫學上不易解釋的相似而非特異性症狀。但是，鑒於電磁場過敏症這一術語已普遍使用，此處將繼續使用這一術語。

盛行率

一般人群中的電磁場過敏症盛行率已有非常廣泛的估計。一項職業醫學中心調查估計，電磁場過敏症為每百萬人口有幾人。但是另一項(病人)互助自助團體的調查，卻有高出甚多的估計值，而其中約10%電磁場過敏症的報告個案被認為是嚴重個案。

電磁場過敏症盛行率和症狀方面，也存在著相當大的地域差異。在瑞典、德國和丹麥報告的電磁場過敏症發生率比英國、奧地利和法國高。終端顯示螢幕(VDU)相關的症狀在北歐各國比較普遍，而且，它們比歐洲其他地方更常見到皮膚病症有關之表徵。與電磁場過敏症個案所報告相類似的症狀，在一般人口中也是相當常見的。

關於電磁場過敏症個案的研究

已有若干研究正進行電磁場過敏症個體暴露於電磁場之探討，目的是在控制的實驗室條件下誘發症狀。

大多數研究指出，電磁場過敏症個體不能比非電磁場過敏症個體更準確地發現電磁場暴露。精心控制和雙盲研究已顯示症狀與電磁場暴露無關。

有人表示，某些電磁場過敏症個體感受的症狀可由與電磁場無關的環境因素引起。例子包括螢光燈的“閃爍”，強烈刺眼的光和視頻顯示單位的其他視覺問題，以及電腦工作站的人機因工程設計不佳。可起作用的其他因素包括工作場所或生活環境的室內空氣~~質量差~~品質或壓力。

還有一些研究指出，這些症狀可能由已存在的精神病症以及因擔憂電磁場健康效應而引起，而不是電磁場暴露本身引起。

結論

電磁場過敏症的特點是因個體案而異的多種非特異性症狀。這些症狀當然是真實的，並且其嚴重程度可有很大差別。無論其原因如何，電磁場過敏症對受影響的個體而言，~~是一個使人喪失能力~~足以導致失能~~的問題~~。電磁場過敏症沒有明確的診斷標準，也沒有科學根據將電磁場過敏症症狀與電磁場暴露聯繫在一起。此外，電磁場過敏症不是醫學診斷，~~也不明確它~~是否是為一個單一的醫學問題也不明確。

醫生： 對受影響個體案的治療應注重健康症狀和臨床表徵，而不是依據病人的主觀感覺受需要減少或消除工作場所或家中的電磁場。需以下評估：

· 醫學評價估，以查明和治療可能造成這些症狀的任何特定殊狀況，

· 心理評價估，以查明可能造成這些症狀的其他精神/心理狀況，

· 評估工作場所和家中可能造成這些症狀的原因，包括室內空氣污染、噪音過高噪音、不良照明品質（閃爍的燈光）或人因工程因素等。可適當的舒解壓力舒解和進行工作環境的其他改善措施。

對於有長期持續症狀和嚴重障礙的電磁場過敏症個體案，治療應主要集中於減少症狀和功能障礙。這應與合格醫學專科醫師（處理症狀的醫學和心理方面）和公衛學者（查明並在必要時控制環境中已知對患者不良健康影響有關的因素）密切合作進行。

治療的目的應是建立有效的醫病關係，幫助制定策略應付當前情況，並鼓勵患者恢復工作和過正常的社會生活。

電磁場過敏症個案： 除由專業人員治療外，(自病人)互助團體可以成為電磁場過敏症個體的寶貴資源。

政府：政府應就電磁場的潛在健康危害向電磁場過敏症個案、衛生醫療專業人員和雇主提供適當的平衡的資訊。這些資訊應包括明確聲明，目前不存在電磁場過敏症與電磁場暴露之間關聯的科學根據。

研究人員：一些研究表明，電磁場過敏症個體的某些生理反應往往超出正常範圍。特別是，有必要在臨床調查中進一步研究中樞神經系統的過度反應和自主神經系統的不平衡，並將這些神經系統反應當作可能治療的考量因素。

世衛組織正在開展哪些工作

世衛組織透過國際電磁場計畫，正在確定研究需求和協調跨國的電磁場研究計畫，使我們能更瞭解與電磁場暴露有關的任何健康風險。重點特別放在低頻電磁場的可能健康後果。關於國際電磁場計畫和電磁場效應的資訊在一系列文件(fact sheets)中以數種語言提供www.who.int/emf/.

進一步讀物：

WHO workshop on electromagnetic hypersensitivity (2004), October 25 -27, Prague, Czech Republic, www.who.int/peh-emf/meetings/hypersensitivity_prague2004/en/index.html

COST244bis (1998) Proceedings from Cost 244bis International Workshop on Electromagnetic Fields and Non-Specific Health Symptoms. Sept 19-20, 1998, Graz, Austria

Bergqvist U and Vogel E (1997) Possible health implications of subjective symptoms and electromagnetic field. A report prepared by a European group of experts for the European Commission, DGV. Arbete och Hälsa, 1997:19. Swedish National Institute for Working Life, Stockholm, Sweden. ISBN 91-7045-438-8.

Rubin GJ, Das Munshi J, Wessely S. (2005) Electromagnetic hypersensitivity: a systematic review of provocation studies. Psychosom Med. 2005 Mar-Apr;67(2):224-32

Seitz H, Stinner D, Eikmann Th, Herr C, Roosli M. (2005) Electromagnetic hypersensitivity (EHS) and subjective health complaints associated with electromagnetic fields of mobile phone communication---a literature review published between 2000 and 2004. Science of the Total Environment, June 20 (Epub ahead of print).

Staudenmayer H. (1999) Environmental Illness, Lewis Publishers, Washington D.C. 1999, ISBN 1-56670-305-0.

WHO296號報告原文網址：

http://www.who.int/mediacentre/factsheets/fs296/en/index.html

Fact sheet N°296
December 2005

Electromagnetic fields and public health

Electromagnetic Hypersensitivity

As societies industrialize and the technological revolution continues, there has been an unprecedented increase in the number and diversity of electromagnetic field (EMF) sources. These sources include video display units (VDUs) associated with computers, mobile phones and their base stations. While these devices have made our life richer, safer and easier, they have been accompanied by concerns about possible health risks due to their EMF emissions.

For some time a number of individuals have reported a variety of health problems that they relate to exposure to EMF. While some individuals report mild symptoms and react by avoiding the fields as best they can, others are so severely affected that they cease work and change their entire lifestyle. This reputed sensitivity to EMF has been generally termed “electromagnetic hypersensitivity” or EHS.

This fact sheet describes what is known about the condition and provides information for helping people with such symptoms. Information provided is based on a WHO Workshop on Electrical Hypersensitivity (Prague, Czech Republic, 2004), an international conference on EMF and non-specific health symptoms (COST244bis, 1998), a European Commission report (Bergqvist and Vogel, 1997) and recent reviews of the literature.

What is EHS?

EHS is characterized by a variety of non-specific symptoms, which afflicted individuals attribute to exposure to EMF. The symptoms most commonly experienced include dermatological symptoms (redness, tingling, and burning sensations) as well as neurasthenic and vegetative symptoms (fatigue, tiredness, concentration difficulties, dizziness, nausea, heart palpitation, and digestive disturbances). The collection of symptoms is not part of any recognized syndrome.

EHS resembles multiple chemical sensitivities (MCS), another disorder associated with low-level environmental exposures to chemicals. Both EHS and MCS are characterized by a range of non-specific symptoms that lack apparent toxicological or physiological basis or independent verification. A more general term for sensitivity to environmental factors is Idiopathic Environmental Intolerance (IEI), which originated from a workshop convened by the International Program on Chemical Safety (IPCS) of the WHO in 1996 in Berlin. IEI is a descriptor without any implication of chemical etiology, immunological sensitivity or EMF susceptibility. IEI incorporates a number of disorders sharing similar non-specific medically unexplained symptoms that adversely affect people. However since the term EHS is in common usage it will continue to be used here.

Prevalence

There is a very wide range of estimates of the prevalence of EHS in the general population. A survey of occupational medical centres estimated the prevalence of EHS to be a few individuals per million in the population. However, a survey of self-help groups yielded much higher estimates. Approximately 10% of reported cases of EHS were considered severe.

There is also considerable geographical variability in prevalence of EHS and in the reported symptoms. The reported incidence of EHS has been higher in Sweden, Germany, and Denmark, than in the United Kingdom, Austria, and France. VDU-related symptoms were more prevalent in Scandinavian countries, and they were more commonly related to skin disorders than elsewhere in Europe. Symptoms similar to those reported by EHS individuals are common in the general population.

Studies on EHS individuals

A number of studies have been conducted where EHS individuals were exposed to EMF similar to those that they attributed to the cause of their symptoms. The aim was to elicit symptoms under controlled laboratory conditions.

The majority of studies indicate that EHS individuals cannot detect EMF exposure any more accurately than non-EHS individuals. Well controlled and conducted double-blind studies have shown that symptoms were not correlated with EMF exposure.

It has been suggested that symptoms experienced by some EHS individuals might arise from environmental factors unrelated to EMF. Examples may include “flicker” from fluorescent lights, glare and other visual problems with VDUs, and poor ergonomic design of computer workstations. Other factors that may play a role include poor indoor air quality or stress in the workplace or living environment.

There are also some indications that these symptoms may be due to pre-existing psychiatric conditions as well as stress reactions as a result of worrying about EMF health effects, rather than the EMF exposure itself.

Conclusions

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.

Physicians: Treatment of affected individuals should focus on the health symptoms and the clinical picture, and not on the person's perceived need for reducing or eliminating EMF in the workplace or home. This requires:

· a medical evaluation to identify and treat any specific conditions that may be responsible for the symptoms,

· a psychological evaluation to identify alternative psychiatric/psychological conditions that may be responsible for the symptoms,

· 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. A reduction of stress and other improvements in the work situation might be appropriate.

For EHS individuals with long lasting symptoms and severe handicaps, 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 medical and psychological aspects of the symptoms) and a hygienist (to identify and, if necessary, control factors in the environment that are known to have adverse health effects of relevance to the patient).

Treatment should aim to establish an effective physician-patient relationship, help develop strategies for coping with the situation and encourage patients to return to work and lead a normal social life.

EHS individuals: Apart from treatment by professionals, self help groups can be a valuable resource for the EHS individual.

Governments: Governments should provide appropriately targeted and balanced information about potential health hazards of EMF to EHS individuals, health-care professionals and employers. The information should include a clear statement that no scientific basis currently exists for a connection between EHS and exposure to EMF.

Researchers: Some studies suggest that certain physiological responses of EHS 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.

What WHO is doing

WHO, through its International EMF Project, is identifying research needs and co-ordinating a world-wide program of EMF studies to allow a better understanding of any health risk associated with EMF exposure. Particular emphasis is placed on possible health consequences of low-level EMF. Information about the EMF Project and EMF effects is provided in a series of fact sheets in several languages www.who.int/emf/.