Assesing the effect of electromagnetic fields on the self-perceived Electromagnetic Hypersensitivity Syndrome

In this work we have measured the high-frequency electromagnetic fields (EMF) present in the rehabilitation areas of several public hospitals in the Balearic Islands. The maximum values of these measurements are all below the recommended maximum values. In addition, we have also passed a questionnaire to assess the prevalence of the self-perceived Electromagnetic Hypersensitivity Syndrome (EHS) among the hospital workers. Around a 5% of the workers reported to consider themselves as presenting the EHS. We have also correlated the values of the measured EMF with the responses to the questionnaire, and no statistically significant correlation has been found.
Keywords: 
Electromagnetic Fields; EHS; Hospital Occupational Health; ORP Conference
Main Author: 
Francesca
Garcias
Universitat de les Illes Balears
España
Co-authors: 
Rodrigo
Picos
Universitat de les Illes Balears
España
Alberto
Caldés
Servei de Salut de les Illes Balears - Hospital Son Espases
España
Carlos
Campillo
Servei de Salut de les Illes Balears
España

Introduction

The technological development applied to healthcare improves the quality of life of citizens. The increasing development of devices and communications media within the healthcare system increases flexibility and mobility that could improve the quality of care, reduce costs of care per patient, and increase efficiency of health services delivered. It also entails the use of artificial electromagnetic radiation devices which causes a constant exposure to ionizing and non-ionizing radiations of both health care professionals and patients.

Short-term electromagnetic radiation safety has been the focus of different studies. Although virtually ignored in the field of clinical safety, it is in fact another cornerstone of the legal basis of the regulations of exposure to these fields, restricted to frequencies between 0 and 300 GHz (non-ionizing radiation). These limits are based on short-term or immediate effects, like muscle stimulation by induced currents, tissue heating due to energy absorption, or burns caused by electric discharges [1].

Regarding its long-term health effects, risk of cancer of exposed individuals is one of the most important. There is consistent data showing a slightly higher risk of leukemia among children living close to power lines. Moreover, the International Agency for Research on Cancer [2] has recently classified radiofrequency electromagnetic fields as possibly being carcinogenic to humans (Group 2B), based on an increased risk for glioma, a malignant type of brain cancer, associated with wireless phone use [3], as well as other effects on short-term wellness [4].

On the other hand, in a large study of the risk of brain tumors in relation to mobile phones, which included substantial numbers of subjects who had used mobile phones for 5-10 years, no increase in the risk of either glioma or meningioma was found to be associated with them. However, biases and methodological pitfalls limit the strength of the conclusions that can be drawn from these analyses and prevent to establish causal relationships [3]. These inconclusive results are a central tenet of virtually all of the studies that have been carried out in this field.

ICNIRP international limits have been taken up in Europe by two regulations: The Council Recommendation 1999/519/EC [5], focusing on the environment, and the Directive 40/2004/EC [6], devoted to the working environment. This Directive applies only to workers, and excludes long-term effects because, according to current scientific evidence, it is still not considered sufficient to cause harm. In Spain, the applicable legislation [7] makes no distinction between occupational and general public limits of exposure to EMF. It also sets the limit values at the ICNIRP Guidelines [1] for general public (Figure 1).

Known effects of EMF include short-term or immediate effects, like muscle stimulation by induced currents, tissue heating due to energy absorption, or burns caused by electrical discharges [1]. Nevertheless, there is still some uncertainty about some effects, including Electromagnetic Hypersensitivity (EHS). The most usual definition of EHS is “a phenomenon where individuals experience adverse health effects while using or being in the vicinity of devices emanating electric, magnetic or electromagnetic fields (EMF)” [8].

The reported sensitivity reactions include a wide range of non-specific symptoms, which afflicted individuals attribute to exposure to EMF. The symptoms most commonly reported 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). Some individuals are so severely affected that they cease work and change their entire lifestyle, while others report mild symptoms and react by avoiding the fields as best they can [9].

In this paper we report some of the results of the study carried out under the coordination of the Health Services Evaluation Unit of the Balearic Health Service to identify and quantify the risks to which workers and patients may be exposed in connection to non-ionizing radiations. Specifically, we present the results of the measurements of the electric field in the most relevant areas of the hospitals in that region.

Fig1

Figure 1: ICNIRP Limits for the electrical field (E) [1].

Methodology

In this work we present two different kinds of field data. First, we have experimentally measured the values of the high frequency electromagnetic fields in the relevant areas of all the public hospitals of the Balearic Islands (Spain). These measurements were performed during 2012.

Electromagnetic Field Measurements

The first step is to gather information on which radiation sources (medical equipment, antennas and mobile phones,...) need to be evaluated. This information was obtained both by visual examination of the area and by analyzing the radio-electric spectrum. Another factor to be considered is the environment: areas where the general public and hospital personnel are exposed have to be selected. Some authors analyzed the exposure of healthcare workers to low-frequency radiation [10-12]. In our case, we are aiming at high-frequency radiation, so their results in terms of the more exposed areas are not directly applicable. We have to ensure that, when measurements are performed, the different radiation sources reach emission levels that can be considered representative of their normal operation.

Before making any measurement, it is necessary to keep in mind the type of radiation and the frequency range within the area being evaluated. In this project we used different devices:

· Spectrum analyzer: the Rohde & Schwarz FSH3 (Munich, Germany) is a device that displays characteristics of each spectral component in a specific range of frequencies (100 kHz-3 GHz). It is used to identify the type of radiation to which someone is exposed (microwave, radio,...) at a particular point.

· Radiation meter: this device measures a medium-high range of frequencies and stores electric field strength and/or magnetic values. The measurements were performed using a Broadband Field Meter Narda Safety Test Solutions (New York, USA) NBM-550, with an EF0391 probe (100 kHz-3 GHz).

The measurements were carried out with the antenna at a height of 1.5 m from the floor with a non-conducting tripod. A first fast exploration of the area was performed by measuring instantaneous samples in order to identify hot (high radiation levels) points. Then, effective field strength measurements were made over a period of 6 minutes at these points of increased radiation. Broadband devices with isotropic probes were used to characterize the environment quickly, measuring the total field. This work has focused on the following public hospitals in the Province of the Balearic Islands (Spain):

  • Son Dureta University Hospital (Palma) (SD), the former referral hospital of the Balearic Islands, is located in the city of Palma, in the island of Mallorca and attends the largest influx of island population (330,000 inhabitants approximately).

· Son Espases University Hospital (Palma) (SE), the new referral hospital of the Balearic Islands, is also located in Palma, serving the same population than Son Dureta.

· Son Llàtzer Hospital (Palma) (SLL) is another hospital close to Palma. It contains all the services (radiology, rehabilitation, emergency, outpatient areas, MRI …).

· Manacor Hospital (Manacor) (MH) is a regional hospital, covering the eastern part of Mallorca, and serving around 150,000 persons. It provides all the services, but MRI.

· Inca Regional Hospital (Inca) (IH) is just outside the center of Inca population in the island of Mallorca and it takes care for providing health service to more than 115,000 people. The hospital consists of a single building, where it was measured radiology, rehabilitation, emergency and outpatient areas.

· Can Misses Hospital (Ibiza) (CMH) is a regional hospital located on the outskirts of Eivissa’s city in the island of Ibiza and serves more than 140,000 inhabitants. Can Misses Hospital has a main building with different zones (emergency, rehabilitation, outpatient areas ...) and an annex which contains nephrology and hemodialysis units.

· Formentera Hospital (FH) is a small hospital in the island of Formentera. This health center serves a population of more than 10,000 people and it has only a main building with different zones (emergency, rehabilitation, outpatient areas …).

· Mateu Orfila Hospital (Maó) (MOH) is a hospital serving the whole population of the island of Menorca, which is around 100,000 people, and is a full-featured hospital, containing all the services (radiology, rehabilitation, emergency, outpatient areas, MRI …).

Questionnaires

Secondly, we have passed a questionnaire based on the work by Eltiti et al [13]. This questionnaire is aimed to determine the degree of electromagnetic hypersensitivity of the subjects. It includes questions to determine the general state of health, as well as the self perception of the subject on his/her response to the presence of electromagnetic fields and what symptoms arise. The responses were offered using a Likert scale graduated from 1 (not at all) to 5 (a great deal). It was passed electronically using Limesurvey [14] installed in a server located in one of our institutions. We also offered the option to complete it in paper, for those workers who did not have access to a computer during work hours. It was launched on January 2012, and a reminder was sent every three months during that year. The survey closed at the end of the year.

Results

                A total of 1,290 measurements were made, distributed in different areas of all hospitals. The median of the electric field measurements was 0.31 V/m (1st quartile: 0.16 V/m; 3rd quartile: 0.67 V/m).

Related to the types of radiation sources measured, telecommunications infrastructure was located mainly in areas where general public was exposed (Hall, Patient Care Point, Waiting rooms ...) and administrative services, while medical devices were located mostly in areas where health workers were exposed. An excerpt of the results is shown in Table 1.

R.A.

Ext.

Halls

Inp.

Inf.

Rad.

Reh.

ICU

Emg.

SD/SE

0.23

0.16

0.25

0.23

0.42

-

2.36

0.19

0.19

SLL

-

0.12

0.79

0.79

-

-

3.24

-

0.16

MH

0.33

0.24

0.26

0.16

2.79

0.29

2.70

0.10

0.27

IH

0.20

0.19

0.14

0.17

0.16

0.07

3.59

0.11

0.47

CMH

0.10

0.22

0.12

0.21

0.34

0.81

5.57

0.10

0.15

FH

0.07

0.16

0.30

0.30

-

0.78

4.44

0.19

0.21

MOH

-

0.35

0.17

0.22

0.16

0.40

3.20

0.29

0.18

Average

0.18

0.21

0.29

0.20

0.77

0.50

3.89

0.16

0.24

Table 1: Root mean squared (rms) values (in V/m) for the high frequency electromagnetic fields in different services for the hospitals. (R.A.: repose areas for staff, Ext: roundabouts of the Hospital, Halls: main halls of the Hospital, Inp.: Inpatient area, Inf.: Informatics department, Rad: Radiology units, Reh: Rehabilitation units, ICU: Intensive care unit, Emg..: Emergency area). The acronyms for the hospitals are explained in the main text.

Concerning the questionnaires, we received a total of 1,502 fully answered questionnaires, from a possible maximum of 9,000 counting all the workers in public hospitals. From these, 1127 (75%) responses were from women. The full demographic distribution of the respondents is shown in Tables 2 and 3.

All

Male

Female

20 - 29

8/194

2/47

6/97

30 - 39

30/546

4/137

26/409

40 - 49

22/452

1/106

21/346

50 - 59

23/262

2/64

21/198

> 59

3/48

0/21

3/27

TOTAL

86/1502

9/375

77/1127

Table 2:  Gender and age distribution of the EHS (first number in each column) and non-EHS groups (second number after the slash).

20 - 29

30 - 39

40 - 49

50 - 59

>59

Directive

0/0

0/0

0/8

1/4

0/2

O&M

0/2

0/9

0/4

0/5

0/0

Midwives

0/1

1/10

1/1

0/2

0/0

Auxiliary

0/4

2/15

0/19

1/12

0/1

Nurse

3/79

13/192

3/109

7/77

1/6

Auxiliary nurse

0/20

5/45

6/55

4/35

1/11

Physiotherapist

4/8

2/21

0/2

0/2

0/0

Services personnel

0/4

0/11

1/37

1/19

0/3

Helpdesk

0/0

0/0

0/1

0/3

0/0

Specialist Auxiliary (Labs, Radiology, etc.)

1/18

2/41

0/14

0/5

0/1

Other

0/17

0/18

0/4

0/2

0/0

Administrative Staff

0/20

4/85

10/100

6/36

1/7

Physician

0/21

1/99

1/98

3/60

0/17

Table 3: Workplace and age distribution of the EHS (first number in each column) and non-EHS groups (second number after the slash).

Discussion

We considered a first division between EHS and non-EHS using one of the criteria proposed by Eltiti et al [13]. That is, we consider the EHS group being those who answered with 4 or 5 to the question whether they consider themselves to be EHS (1-not at all, 5-a great deal). The number of people in this category is 86 (5.7%), in line with other similar reports [13]. From these 86 self-perceived EHS individuals, 77 (89%) were women. The age and gender distributions for each group are outlined in table 2, while in table 3 we show the age distributions considering the workplace.

As a first test, we check the distribution of EHS against age with a c2 test, and we conclude that EHS is independent of age (p-value of 0.25, a=0.05). Anyway, considering the gender distribution, the c2 test provides a p-value of 0.001 so we can assert that, in fact, there is a relation between gender and self-perception of EHS. In this case, data show that men are less prone to consider themselves EHS than women.

The values of the EMF in Table 1 were correlated with the answers to the questionnaire. Specifically, we have correlated these rms values with the perceived symptoms for both the non-EHS and the self-perceived EHS groups. We have found no significant statistical correlation between the values of the EMF and the mean values of the symptoms neither for the EHS group (r<0.00001) nor for the EHS group (r=-0.141, p(a=0.05)=0.193). It has to be noted that the correlation coefficient for the latter is negative, implying that being exposed to higher values of the EMF would reduce the perceived symptoms, but the high value of p hints to a purely random effect. We have also studied these correlations segregating by gender. The results hint that there is no correlations in the control group (r=0.001 for women, r=-0.02 for men). The analysis of the EHS group shows that in the case of women the correlation is very low and probably due to random chances (r=-0.133, p(a=0.05)=0.89), while men show a notable correlation (r=-0.367, p(a=0.05)=0.90), but also due to purely random effects, which are worsened by the small size of the set (there are only 9 men considering themselves as EHS).

Conclusion

In this study we have found no experimental evidence of an actual correlation between the exposure to high frequency electromagnetic fields and the presence of symptoms associated with EHS in the scientific literature. In addition, it has been found that the EHS group present a higher sensitivity to their own symptoms, which may be hinting to a nocebo effect.

We have determined that the prevalence of self-perceived EHS is a 5.7% in the hospitals workforce. We have also found a clear difference between the incidence of EHS in the masculine and feminine populations, the latter being more prone to consider themselves as EHS. We suppose that the difference is due to psychosocial factors. Age has not been found to play any significant role in the self-perception as EHS.

Acknowledgment

A preliminary versión of this paper was presented in ORP Conference’2014. Part of this work has been supported by the Fundación Mapfre. We also wish to thank Dr. Ángel Arturo López for his help with the questionnaire design.

References

  • 1. Ahlbom A, Bergqvist U, Bernhardt J, Césarini JP, Court LA, Grandolfo M, et al. International Commission on NonIonizing Radiation Protection. Guidelines for limiting exposure to timevarying electric, magnetic, and electromagnetic fields (up to 300 GHz). Health Phys 1998; 74(4):494522.
  • 2. International Agency for Research on Cancer. Press release 208 [Internet]. Lyon. Available from: http://www.iarc.fr/en/mediacentre/pr/2011/pdfs/pr208_E.pdf
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  • 6. Directive 40/2004/EC of the European Parliament and of the Council of 29 April 2004 on the minimum health and safety requirements regarding the exposure of workers to the risks arising from physical agents (electromagnetic fields). (Official Journal of the European Communities, L159/1, 30/04/2004).
  • 7. Real Decreto 1066/2001, de 28 de septiembre, del Ministerio de la Presidencia, por el que se aprueba el Reglamento que establece condiciones de protección del dominio público radioeléctrico, restricciones a las emisiones radioeléctricas y medidas de protección sanitaria frente a emisiones radioeléctricas. (BOE, núm. 234, 29/09/2001).
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  • 9. World Health Organization. 2004. WHO international seminar and working group meeting on EMF hypersensitivity.
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