Content uploaded by Enrique A. Navarro
Author content
All content in this area was uploaded by Enrique A. Navarro on Nov 29, 2014
Content may be subject to copyright.
3rd INTERNATIONAL WORKSHOP
ON
BIOLOGICAL EFFECTS OF ELECTROMAGNETIC FIELDS
4 - 8 October 2004, Kos, Greece
PAPER PROFILE FORM
Paper Title: The Microwave Syndrom – further Aspects of a Spanish Study
Keywords: Mobile Phone Basestations, Health survey, exposure assessment, risk assessment,
public health
Authors: Oberfeld Gerd, Navarro A. Enrique, Portoles Manuel, Maestu Ceferino,
Gomez-Perretta Claudio
Short C.V. for the Presenting Author:
oMedical doctor
osince 1992 in the permanent staff of the Public Health Department of the Government of
Salzburg, Austria
oTrained in: public health, environmental health, environmental epidemiology, health risk
assessment, exposure assessment
osince 1994 head of the environmental health unit of the Austrian Medical Association
Equipment available for presentation: Overhead projector, slide projector, video projector, laser
pointer.
Sponsored by:
Electronics - Telecom &
Applications Laboratory
Physics Department
University of Ioannina
Dept. of Applied Technologies
and Mobile Communication Lab.
Institute of Informatics and
Telecommunications
N
CSR “Demokritos”
THE MICROWAVE SYNDROME - FURTHER ASPECTS OF A SPANISH STUDY
3
THE MICROWAVE SYNDROME –
FURTHER ASPECTS OF A SPANISH STUDY
Oberfeld Gerd1, Navarro A. Enrique3,
Portoles Manuel2, Maestu Ceferino4, Gomez-Perretta Claudio2
1) Public Health Department Salzburg, Austria
2) University Hospital La Fe, Valencia, Spain
3) Department of Applied Physics, University Valencia, Spain
4) Foundation European Bioelectromagnetism (FEB) Madrid, Spain
Adress Corresponding author: Dr. Gerd Oberfeld, Public Health Department Salzburg,
PO Box 527, 5010 Salzburg, Phone 0043 662 8042-2969, Fax 0043 66 8042-3056,
gerd.oberfeld@salzburg.gv.at
Abstract
A health survey was carried out in La Ñora, Murcia, Spain, in the vicinity of two GSM 900/1800 MHz cellular
phone base stations. The E-field (~ 400 MHz – 3 GHz) measured in the bedroom was divided in tertiles (0.02 –
0.04 / 0.05 – 0.22 / 0.25 – 1.29 V/m). Spectrum analysis revealed the main contribution and variation for the E-
field from the GSM base station. The adjusted (sex, age, distance) logistic regression model showed statistically
significant positive exposure-response associations between the E-field and the following variables: fatigue,
irritability, headaches, nausea, loss of appetite, sleeping disorder, depressive tendency, feeling of discomfort,
difficulty in concentration, loss of memory, visual disorder, dizziness and cardiovascular problems. The
inclusion of the distance, which might be a proxy for the sometimes raised “concerns explanation”, did not alter
the model substantially. These results support the first statistical analysis based on two groups (arithmetic mean
0,65 V/m versus 0,2 V/m) as well as the correlation coefficients between the E-field and the symptoms (Navarro
et al, “The Microwave Syndrome: A preliminary Study in Spain”, Electromagnetic Biology and Medicine,
Volume 22, Issue 2, (2003): 161 – 169). Based on the data of this study the advice would be to strive for levels
not higher than 0.02 V/m for the sum total, which is equal to a power density of 0.0001 µW/cm² or 1 µW/m²,
which is the indoor exposure value for GSM base stations proposed on empirical evidence by the Public Health
Office of the Government of Salzburg in 2002.
Introduction
The relationship between biological/health effects and electromagnetic exposure has been widely recognized
from epidemiological and experimental studies. Even some institutional consensus has been reached and formal
health risk assessments for exposure to ELF, extremely low frequency fields, e.g. from powerlines and electric
appliances, have recently been scheduled. In 2002 the first IARC review on this topic classified ELF magnetic
fields as “ possibly human carcinogen “ based on epidemiological studies of childhood leukemia [1]. In 2002 the
California Department of Health judged ELF magnetic fields at least possibly related with leukemia in children
and adults, brain tumors in adults, miscarriage and motor neuron disease [2].
With respect to radiofrequency (30 kHz – 300 MHz) and microwave exposure (300 MHz – 300 GHz) the
scientific evidence from in vitro, in vivo and epidemiological studies shows a great spectrum of biological/health
effects at low level exposures [3, 4, 5, 6, 7, 8, 9]. A specific symptomatology in humans linked to radiofrequency
and microwaves, named “microwave sickness” or “radiofrequency syndrome” was described at low level
exposure which include headache, fatigue, irritability, loss of appetite, sleeping disorders, difficulties in
concentration or memory, and depression [10].
The growing use of mobile communication, GSM 900/1800, cordless telephones etc in the last decade has
reintroduced concerns about whether some health risks could derive from microwave exposure, especially from
mobile phones and their basestations. In contrast to the public debate on health risks from mobile phone base
stations, only three epidemiological studies on this issue have been published until now. A study done in France
OBERFELD, GOMEZ-PERRETTA, NAVARRO, PORTOLES, MAESTU
4
by Santini showed significant associations between symptoms fitting to the microwave sickness and the distance
to mobile phone base stations [11]. It should be noted that the health related symptoms were most frequently
reported at a distance of 50 – 100 m, which fits perfectly to the area with the highest microwave exposure in
urban areas, where the main beam of the antennas usually hits the first houses. The second study done in Austria
showed significant positive associations between the frequency selective measured electric field (GSM
900/1800) in the bedroom and cardiovascular symptoms, irrespective of the concerns of the people under study
[12]. The third study was published by our group [13] where we measured the electric field via a broadband
device in the bedroom of 97 participants in La Ñora, Murcia, Spain. The statistical analysis showed significantly
higher symptom scores in 9 out of 16 symptoms in the group having an exposure of 0.65 V/m compared to the
control group having an exposure of 0.2 V/m, both as an average mean. In the same paper we reported also
significant correlation coefficients between the measured electric field and fourteen out of sixteen health related
symptoms.
The aim of this paper is to present additional statistical tests like logistic regression of the La Ñora data set and a
detailed investigation of the EMF spectrum in six bedrooms (8 participants) done on July 3rd, 2004.
Geographical Area and Time Schedule
The study was done in La Ñora, a town in the south-east of Spain, close to Murcia, with 1900 inhabitants,
situated on the slope of a hill. For the mobile phone coverage of La Ñora two masts had been sited on two
different positions near the top of the hill above the village. The start of the transmission of both stations is not
clear. However for the GSM 900 base station the siting is not earlier than 1997/1998, for the GSM 1800 base
station was sited in December 1999. The questionnaires have been distributed in October 2000 and collected in
November 2000. Broad band measurements (~400 MHz – 3 GHz) in 97 bedrooms as well as some frequency
selective measurements have been done in February and March 2001.
In July 2004 frequency selective measurements were done in 6 bedrooms of former study participants.
Questionnaire
We used a questionnaire, translated to Spanish, of the Santini publication [10] which refers to demographic data:
Address, sex, age, distance to mobile phone basestations, exposure time (years, days per week, hours per day).
The questionnaire also collected information about proximity to power lines < 100 m, proximity to transformer
stations < 10 m, use of personal computers > 2 hours per day and the use of cellular phones > 20 minutes per
day. Finally a symptom checklist allowed to know the frequency of 16 health related symptoms: 0 = never, 1 =
sometimes, 2 = often, 3 = very often.
Many of the symptoms were those described as microwave/radiofrequency syndrom/sickness: Fatigue,
irritability, headache, nausea, loss of appetite, sleeping disorders, depression, feeling of discomfort, difficulty in
concentration, loss of memory, skin alterations, visual disorder, auditory disorder, dizziness, gait difficulty and
cardiovascular alterations. The questionnaires were distributed in La Ñora in frequently used locations (hair
dresser, pharmacy) in October/November 2000 and collected in November/December 2000. From 144
questionnaires returned, 97 measurements in the bedrooms were done in 2001. The difference of 47 subjects was
due to the impossibility to read the name or adress in order to get the contact, no interest in the measurements,
not at home at the scheduled measurement time or symptoms of the health questionnaire checked with an “x”
instead of the proposed numbers “0”, “1”, “2”, or “3”. In 2004 the analysis of the La Ñora data set had been done
with n=94 subjects having full information on exposure values from 2001, sex, age and symptoms except for one
subject, where all informations were available except for the “skin disorder question” n=93.
Exposure Assessment
The exposure to mobile phone basestations was assessed in 2001 with a portable broad band measurement
device (~ 400 MHz – 3 GHz) called LX-1435. The electric field meter had been calibrated with a network
analyser HP-8510C inside the anechoic chamber of the University of Valencia, Spain. The electric field probe
was held around 1 meter from the walls and 1.2 meters above the ground, to avoid reflection of the waves in the
walls and metallic structures and moved around a circle of 25 centimeters´ radius, orientating the dipole antenna
to get the maximum electric field strength above the bed.
The measurements were performed from 11:00 h to 19:00 h on February 24th, 2001, and on March 10th, 2001, in
the respondents´ home. The bedroom was chosen because the pineal gland and its hormone melatonine is
considered one of the target organs for EMF, having secretion peaks during the sleep.
THE MICROWAVE SYNDROME - FURTHER ASPECTS OF A SPANISH STUDY
5
To check the intensity of TV and radio channels (ultra short wave range), as well as the number and type of
channels of the GSM 900/1800 base stations, measurements of the spectral power density were performed with a
probe antenna and a portable spectrum analyser. The probe was mounted on a linen phenolic tripod about 1.2
meters above ground. Location of the probe was the same in both days, on a hill next to the town. With the
spectrum analyser we scanned the GSM 900/1800 MHz bands, at the beginning of the journey, taking the
average for a period of 6 minutes. The spectrum was similar in both days, with a difference in the peak
estimation (carriers of the channels) of about 1 dB in radio and TV channels, GSM 900/1800 showed small
differences, around 3 dB, associated to the working channels that were dependent on the traffic of cellular
phones.
On July 3rd, 2004 from 11:00 to 19:00 h the spectrum of the electric field from 80 MHz – 2.5 GHz was measured
in six bedrooms in La Ñora. The points of measurement were randomly selected from the study population
which had been divided in three exposure groups (low, intermediate, high) with respect to the measured electric
field in 2001. The aim was to check the exposure situation inside the houses in several places to validate the
measurements of 2001 and to get the portion of radio, TV and GSM of the electromagnetic spectrum. A
calibrated hand-held spectrum analyzer, FSH3 (100 kHz – 3 GHz) from the manufacturer Rhode & Schwarz,
Germany and calibrated electric-field probes EFS 9218 (9 kHz – 300 MHz) and USLP 9143 (300 MHz – 5 GHz)
from the manufacturer Schwarzbeck, Germany were used. A volume of about one m³ above the surface of the
bed was examined holding the antennas in different polarization directions as well as different directions in order
to pick up the highest signals. The spectrum analyzer was adjusted: detector: max peak, trace: max hold. In order
to differentiate broadcast control channels (BCCH) from traffic channels (TCH) both GSM spectra (GSM
900/1800) had been analysed at the time of measurements. The traces were stored in the spectrum analyzer and
analysed via FSH View Version 7.0 on the PC afterwards.
Results
From n=94 participants under study, 47 were female, 47 male. The age span was 14 to 81 years, with a median
age of 39 years. In the questionnaire the distances to the next GSM 900/1800 base stations were given in six
different categories.
Table 1: Distance to next GSM 900/1800 base stations
Distance Frequency Percent
< 10 m 7 7.4
10 – 50 m 6 6.4
50 – 100 m 9 9.6
100 – 200 m 30 31.9
200 – 300 m 14 14.9
> 300 m 28 29.8
Total 94 100.0
93 % reported to be exposed to the mobile phone base stations for more than one year. The time spent in the
house of the study site, was more than 8 hours per day for at least 6 days in 94 % of the respondents.
17 % reported to be exposed to an electric transformer distance less than 10 m. 43 % reported to live closer than
100 m to a high voltage power line. 40 % reported that they live at a distance of less than 4 km from a radio / TV
transmitter. Using a mobile phone for more than 20 minutes per day was reported by 29 %. Working on a
personal computer more than two hours per day was reported by 14 % of the study participants.
TV and radio channels maintained constant intensity during the 2001 measurements, however the traffic
channels of the mobile phone base stations (GSM 900/1800) showed typical fluctuations. Table 2 shows the
measured broad band electric field in V/m and the corresponding power density in µW/cm² and µW/m² in the
bedroom in 2001.
OBERFELD, GOMEZ-PERRETTA, NAVARRO, PORTOLES, MAESTU
6
Table 2: Broad band measurement in the bedroom 2001
E-field
[V/m] Power density
[µW/cm²] Power density
[µW/m²]
n valid 94 94 94
missing 0 0 0
average 0.27 0.051615 516.15
median 0.11 0.003157 31.57
SD 0.35 0.107775 1077.75
Minimum 0.02 0.000088 0.88
Maximum 1.29 0.442028 4420.28
The frequency selective measurements done in 2004 in six bedrooms showed that the variance of the broad band
signal is mostly due to differences in the strength of the GSM 900/1800 signal. Because the broad band
measurements had an attenuation in the FM frequency range of 15 dB the contribution of the FM signals to the
broad band results are of small influence. The TV signals showed also to be quite small in comparison to the
GSM 900/1800 signal as well. In order to attribute the proportion of different signals to a health outcome a
frequency selective exposure assessment on an individual level is prefered. Figure 1 shows the results of the
frequency selective measurements of 2004.
Figure 1: Exposure distribution (GSM 900/1800, FM, TV) in six bedrooms 2004
Exposure distribution FM / TV / GSM in La Nora (Murcia), Spain, July 3, 2004
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
0,45
0,50
high high intermediate intermediate low low
exposure category
[V/m]
Sum GSM [V/m]
Sum FM [V/m]
Sum TV [V/m]
For the logistic regression model we divided the broad band measured electric field in three exposure categories:
Low exposure 0.02 – 0.04 V/m (1 – 4 µW/m²), intermediate exposure 0.05 – 0.22 V/m (6 – 128 µW/m²) and
high exposure 0.25 – 1.29 V/m (165 – 4400 µW/m²). We calculated a raw model to derive the odds ratio (OR)
and the corresponding 95%-confidence interval (95%-CI) as well as the probability value (p-value) for all 16
health related symptoms for the intermediate and the high exposure category – using the low exposure category
as the reference. In the second model we controlled for sex and age. In the third model we controlled for sex, age
and distance to the next mobile phone base station reported by the study participants. The distance was added in
order to see if there is any significant contribution to the model (which still includes the measured electric field,
sex and age) from this variable. If one assumes the reversed distance as a proxy for concerns from the antennas,
the reversed distance might show up as a variable with a certain amount of explanation of the model. In two out
THE MICROWAVE SYNDROME - FURTHER ASPECTS OF A SPANISH STUDY
7
of 16 symptoms the reversed distance showed a significant contribution to the model in addition to the sex and
age adjusted model. The variables being “sleeping disorders” with OR 1.47 (95%-CI 1.01 – 2.15) and
“dizziness” with OR 1.71 (95%-CI 1.17 – 2.51). In comparison with the explanation of the measured E-field, the
contribution is very small. See table 5, where the symptom “sleeping disorder” was associated with the measured
E-field OR 10.39 (95%-CI 2.43 – 44.42) and OR 10.61 (95%-CI 2.88 – 39.19) and “dizziness” OR 2.98 (95%-CI
0.62 – 14.20) and OR 8.36 (95%-CI 1.95 – 35.82). A relevant influence of the reversed distance would result in a
substantially alteration of the odds ratios associated with the E-field, which is not the case.
We also calculated logistic regression models including other variables like living closer than 100 m to high
voltage power lines or 10 m to a transformer, living closer than 4 km to a radio / TV station, use of a computer >
2h/day or a cell phone > 20 minutes/day. For some of the above mentioned variables we found a significant
contribution to the explanation of the model (data not shown) for few of the symptom variables which did not
alter the overall associations of the models presented in this paper. For future studies we advice that the exposure
to high voltage power lines and transformers as well as to radio / TV stations should be measured on an
individual level in order to reduce exposure misclassification.
In 13 out of the 16 health related symptoms significant exposure-response relationships and very high and
significant odds ratios for the measured electric fields were found which is one of the main findings of this study.
An other important finding is that 10 out of 16 symptoms showed significantly elevated OR between the
reference exposure category (0.02 – 0.04 V/m) and even the intermediate exposure category (0.05 – 0.22 V/m).
In order to derive guideline values for the protection of public health from electromagnetic fields from mobile
phone base stations GSM 900/1800 MHz, one should take into account that epidemiological studies usually
underestimate individual risks, as well as the uncertainty with respect to the reference exposure category, which
could be at a sufficiently low level but that is not known in this study and an open question in this issue as well.
In order to take this arguments into account a provisional reference level of about 0,02 V/m for the sum total of
electric fields from mobile phone base stations GSM 900/1800 MHz is recommended and is in line with the level
recommended in 2002 by the Public Health Office of the Government of Salzburg, based on empirical evidence.
Table 3 shows the raw logistic regression model. Table 4 shows the sex and age adjusted model. Table 5 shows
the sex, age and distance adjusted model.
Table 3: Raw Model
0.05 – 0.22 V/m
(6 – 128 µW/m²) 0.25 – 1.29 V/m
(165 – 4400 µW/m²)
Health Outcome OR 95%-CI p OR 95%-CI p p for the
trend
Fatigue 23.46 2.77 – 198.82 0.0038 33.88 4.16 – 276.04 0.0010 0.0044
Irritability 3.71 1.19 – 11.55 0.0234 10.73 3.48 – 33.13 0.0000 0.0002
Headaches 7.46 2.10 – 26.55 0.0019 6.56 2.14 – 20.05 0.0010 0.0005
N
ausea 7.62 0.83 – 69.89 0.0726 14.67 1.77 – 121.49 0.0128 0.0382
Loss of Appetite 5.82 0.61 – 55.61 0.1263 24.00 2.94 – 195.94 0.0030 0.0028
Sleeping Disorder 7.67 2.36 – 24.86 0.0007 6.64 2.30 – 19.20 0.0005 0.0003
Depressive Tendency 32.00 3.79 – 270.21 0.0015 42.66 5.23 – 348.33 0.0005 0.0021
Feeling of Discomfort 4.80 1.41 – 16.33 0.0121 12.21 3.72 – 40.12 0.0000 0.0002
Difficulty in Concentration 8.46 2.31 – 31.00 0.0013 18.12 5.05 – 64.99 0.0000 0.0000
Loss of Memory 1.65 0.53 – 5.14 0.3844 4.69 1.65 – 13.32 0.0037 0.0108
Skin Disorder 4.50 0.82 – 24.55 0.0825 5.19 1.08 – 26.21 0.0463 0.1278
Visual Disorder 1.65 0.53 – 5.14 0.3844 3.31 1.17 – 9.32 0.0236 0.0707
Hearing Disorder 2.72 0.87 – 8.52 0.0852 1.10 0.35 – 3.47 0.8702 0.1534
Dizziness 5.29 1.26 – 22.25 0.0229 9.44 2.43 – 36.77 0.0012 0.0053
Gait Difficulties 0.74 0.21 – 2.62 0.6454 1.08 0.36 – 3.25 0.8886 0.8321
Cardiovascular Problems 9.60 1.07 – 85.72 0.0429 14.67 1.77 – 121.49 0.0128 0.0442
OBERFELD, GOMEZ-PERRETTA, NAVARRO, PORTOLES, MAESTU
8
Table 4: Age and Sex adjusted model
0.05 – 0.22 V/m
(6 – 128 µW/m²) 0.25 – 1.29 V/m
(165 – 4400 µW/m²)
Health Outcome OR 95%-CI p OR 95%-CI p p for the
trend
Fatigue 25.79 2.94 – 225.85 0.0033 37.72 4.42 – 321.49 0.0009 0.0040
Irritability 3.36 1.06 – 10.66 0.0395 9.60 3.05 – 30.26 0.0001 0.0006
Headaches 8.06 2.14 – 30.31 0.0020 7.29 2.22 – 23.94 0.0011 0.0007
N
ausea 7.53 0.80 – 70.75 0.0774 14.33 1.68 – 122.55 0.0150 0.0445
Loss of Appetite 6.03 0.60 – 60.19 0.1260 25.84 2.98 – 223.80 0.0032 0.0031
Sleeping Disorder 13.982 3.50 – 55.85 0.0002 12.39 3.47 – 44.26 0.0001 0.0001
Depressive Tendency 44.87 4.85 – 414.69 0.0008 64.28 7.05 – 586.27 0.0002 0.0011
Feeling of Discomfort 4.34 1.25 – 15.03 0.0207 10.97 3.27 – 36.77 0.0001 0.0005
Difficulty in Concentration 9.40 2.44 – 36.21 0.0011 20.55 5.35 – 79.00 0.0000 0.0001
Loss of Memory 2.40 0.70 – 8.26 0.1642 7.91 2.37 – 26.35 0.0008 0.0027
Skin Disorder 6.25 1.05 – 37.13 0.0437 7.67 1.36 – 43.44 0.0212 0.0647
Visual Disorder 2.57 0.74 – 9.08 0.1380 5.88 1.75 – 19.74 0.0041 0.0158
Hearing Disorder 4.45 1.23 – 16.13 0.0231 1.75 0.49 – 6.24 0.3859 0.0643
Dizziness 5.37 1.24 – 23.16 0.0243 9.70 2.39 – 39.33 0.0015 0.0063
Gait Difficulties 1.09 0.28 – 4.24 0.8970 1.86 0.54 – 6.41 0.3235 0.5629
Cardiovascular Problems 12.56 1.32 – 118.99 0.0274 20.43 2.26 – 184.95 0.0073 0.0267
Table 5: Age, Sex and distance adjusted model
0.05 – 0.22 V/m
(6 – 128 µW/m²) 0.25 – 1.29 V/m
(165 – 4400 µW/m²)
Health Outcome OR 95%-CI p OR 95%-CI p p for the
trend
Fatigue 28.53 3.03 – 268.78 0.0034 40.11 4.56 – 352.44 0.0009 0.0039
Irritability 3.12 0.91 – 10.68 0.0704 9.22 2.86 – 29.67 0.0002 0.0009
Headaches 5.99 1.50 – 23.93 0.0113 6.10 1.80 – 20.65 0.0037 0.0050
N
ausea 5.92 0.60 – 58.68 0.1288 12.80 1.48 – 110.64 0.0205 0.0499
Loss of Appetite 6.66 0.62 – 71.52 0.1175 27.53 3,07 – 247.03 0.0031 0.0030
Sleeping Disorder 10.39 2.43 – 44.42 0.0016 10.61 2.88 – 39.19 0.0004 0.0008
Depressive Tendency 39.41 4.02 – 386.40 0.0016 59.39 6.41 – 550.11 0.0003 0.0016
Feeling of Discomfort 4.29 1.14 – 16.15 0.0314 10.90 3.16 – 37.56 0.0002 0.0007
Difficulty in Concentration 8.27 2.01 – 34.01 0.0034 19.17 4.91 – 74.77 0.0000 0.0001
Loss of Memory 2.35 0.62 – 8.89 0.2090 7.81 2.27 – 26.82 0.0011 0.0031
Skin Disorder 7.04 1.06 – 46.62 0.0429 8.22 1.39 – 48.51 0.0201 0.0628
Visual Disorder 2.48 0.65 – 9.44 0.1830 5.75 1.68 – 19.75 0.0054 0.0186
Hearing Disorder 3.89 0.99 – 15.21 0.0510 1.63 0.45 – 5.95 0.4572 0.1285
Dizziness 2.98 0.62 – 14.20 0.1712 8.36 1.95 – 35.82 0.0042 0.0117
Gait Difficulties 1.32 0.30 – 5.84 0.7114 2.07 0.57 – 7.50 0.2690 0.5211
Cardiovascular Problems 9.42 0.93 – 95.07 0.0572 17.87 1.96 – 162.76 0.0105 0.0333
THE MICROWAVE SYNDROME - FURTHER ASPECTS OF A SPANISH STUDY
9
Summary
Frequency selective measurements done in July 2004 (n=6) showed that the main contribution and the main
variability of the broad band signal measured in February and March 2001 is due to GSM 900/1800 signals
(n=97). This is further supported by the fact that the dipol antenna used in 2001 is quite insensitive to
frequencies below 400 MHz which is related to FM (80 – 110 MHz) and that the TV channels were quite weak
in comparison to the GSM signals. However we would prefer to have frequency selective personal exposure
values for all important signals of the electromagnetic spectrum in future studies.
For the logistic regression we devided the broad band measurements of the electric field in three exposure
groups, the low exposure group served as the reference category. We calculated the odds ratios and 95% CI for
the raw model, an age and sex adjusted model and an age, sex and distance adjusted model. All models showed
statistical significant associations between the measured electric field (~ 400 MHz – 3 GHz) and 13 out of 16
health related symptoms. The strongest five associations found are depressive tendency, fatigue, sleeping
disorder, difficulty in concentration and cardiovascular problems. The symptoms associated are in line with the
symptoms reported in the literature as “Microwave Syndrom”. The odds ratios are quite high having small p-
values. Some kind of selection bias cannot be ruled out, because of the way the questionnaires were distributed,
but that would affect more or less all cases and therefore affect the odds ratios not substantially. The introduction
of the reversed distance to the nearest base station, which might serve as a surrogat for the sometimes claimed
“concerns explanation” for health related symptoms attributed to mobile phone base stations, did not alter the
odds ratios substantially and the OR associated with the measured electric fields remained at their high level. It
should be noted that the findings of this study might be of great importance for Public Health and should be
taken seriously. Further epidemiological studies are warranted but do not preclude measures to reduce
microwave exposures from GSM 900/1800 base stations now. Based on the data of this study the advice would
be to strive for levels not higher than 0.02 V/m for the sum total, which is equal to a power density of 0.0001
µW/cm² or 1 µW/m², which is the indoor exposure value for GSM base stations proposed on empirical evidence
by the Public Health Office of the Government of Salzburg in 2002 [14].
Acknowledgements
We would like to thank Mrs. Angeles Martinez Gomez for her great support during the field work in La Ñora as
well as the Spanish Ministry of Science and Technology for the grant FIT Number 070000-2002-58.
References
[1] Non-Ionizing Radiation, Part 1: Static and Extremely Low-Frequency (ELF) Electric and Magnetic Fields,
IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, VOLUME 80 (2002), World Health
Organization, International Agency for Research on Cancer (IARC), Lyon.
[2] An Evaluation of the Possible Risks From Electric and Magnetic Fields (EMFs) From Power Lines, Internal
Wiring, Electrical Occupations and Appliance; California department of health;
www.dhs.ca.gov/ehib/emf/RiskEvaluation/riskeval.html
[3] Lai, H.; Horita, A.; Chou, C.K.; Guy, A.W.. “Effects of low-level microwave irradiation on amphetamine
hyperthermia are blockable by naloxone and classically conditionable”. Psychopharmacology. 1984, 88:354-61.
[4] Dutta, S.K.; Ghosh, B.; Blackman, C.F. “Radiofrequency radiation-induced calcium ion efflux enhancement
from human and other neuroblastoma cells in culture”. Bioelectromagnetics. 1989, 10:197-202.
[5] Lai, H.; Singh, N.P. “Single- and double-strand DNA breaks in rat brain cells after acute exposure to
radiofrequency electromagnetic radiation”. Int. J. Radiat. Biol. 1996, 69:513-21.
[6] Goldsmith, J.R. "Epidemiologic evidence relevant to radar (microwave) effects". Environmental Health
Perspectives. 1997, 105 (Suppl 6):1579-87.
[7] de Pomerai, D.; Daniells, C.; David, H.; Allan, J.; Duce, I.; Mutwakil, M.; Thomas, D.; Sewell, P.; Tattersall,
J.; Jones, D.; Candido, P. “Non-thermal heat-shock response to microwaves”. Nature. 2000, 405:417-8.
OBERFELD, GOMEZ-PERRETTA, NAVARRO, PORTOLES, MAESTU
10
[8] Hardell, L.; Hallquist, A.; Hansson Mild, K.; Carlberg, M.; Pahlson, A.; Lilja, A.: Cellular and cordless
Telephones and the risk for brain tumours; European Journal of Cancer Prevention 2002, 11, S. 377 – 386
[9] Salford L. G.; Brun A. E.; Eberhard J. L.; Malmgren L.; Perrson B. R. R.: Nerve Cell Damage in Mammalian
Brain after Exposure to Microwaves from GSM Mobile Phones; in: Environ Health Perspect 111, S. 881-883
(2003); http://ehp.niehs.nih.gov/docs/2003/6039/abstract.html
[10] Johnson-Liakouris, A.J. "Radiofrequency (RF) Sickness in the Lilienfeld Study: an effect of modulated
microwaves?". Arch. Environ. Health. 1998, 53:236-238.
[11] Santini, R.; Santini, P.; Danze, J.M.; Le Ruz, P.; Seigne, M.: Study of the health of people living in the
vicinity of mobile phone base stations: 1st Influence of distance and sex; Pathol Biol 2002; 50; S. 369 - 373.
[12] Hutter, H-P.; Moshammer,H.; Kundi, K.: Mobile Telephone Base-Stations: Effects on Health and Well-
beeing; Presented at the 2nd Workshop on Biological Effects of EMFs, 7. - 11. Oktober 2002, Rhodos, Greece.
[13] Navarro A. E.; Segura J.; Portolés M.; Gómez-Perretta de Mateo C.: The Microwave Syndrome: A
Preliminary Study in Spain; in: Electromagnetic Biology and Medicine (formerly Electro- and Magnetobiology),
Volume 22, Issue 2, (2003); S. 161 – 169.
[14] Website of the Public Health Office, Environmental Health, Government of Salzburg, Austria:
www.salzburg.gv.at/umweltmedizin
