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Medical/biological study (experimental study)

Effects of short-term W-CDMA mobile phone base station exposure on women with or without mobile phone related symptoms.

Published in: Bioelectromagnetics 2009; 30 (2): 100-113

Aim of study (acc. to author)

To measure the effects of short-term exposure to a W-CDMA mobile phone base station, and to observe whether they differ between women with mobile phone related symptoms and women without symptoms.
Background/further details: 5000 questionaires including the frequency of mobile phone use and the presence/absence of mobile phone related symptoms were sent out to randomly sampled Japanese women (between 20 and 60 years). From 2472 valid responses 11 subjects with mobile phone related symptoms and 43 control subjects were recruited for a provocation study. Four different exposure conditions (each 30 min) were tested: continuous, intermittent, sham exposure with noise and sham exposure without noise.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2.14 GHz
Exposure duration: continuous for 30 min
Exposure 2: 2.14 GHz
Exposure duration: intermittent, 5 min on or off, for 30 min
General information
There were four exposure conditions used: continuous EMF, intermittent EMF, sham, and noise exposure. During the tests performed on two days, each of the four conditions was administered to each subject in a double-blind, randomized order that was counterbalanced across subjects. Two sessions per day, each lasting about 90 min, were separated by at least 2 h.
Exposure 1
Main characteristics
Frequency 2.14 GHz
Type
Exposure duration continuous for 30 min
Modulation
Modulation type cf. additional info
Additional info W-CDMA down-link signal similar to the one used in previous studies [Zwamborn et al., 2003; Regel et al., 2006] but with 64 dedicated physical channels added
Exposure setup
Exposure source
Distance between exposed object and exposure source 3 m
Chamber The shielded room had an area of 5.3 x 3.0 m² and a height of 2.745 m, an ambient temperature of 23 °C, a humidity of 50%, and a sound level below 40 dBA. Flat wave absorbers (23.6 dB at 2.0 GHz) covered most of the floor, ceiling, and three walls in front of the horn antenna.
Setup The subject was seated on a polypropylene chair in front of a wooden desk with the psychological test equipment. The horn antenna, 1.15 m tall, was placed behind the subject and to the left at a height of 0.755 m being approximately that of an average Japanese female aged 20-59 sitting on a 0.4-m high chair.
Sham exposure A sham exposure was conducted.
Additional info The noise used was produced by and recorded near the RF power amplifier used in the experiment. The noise level at the subject's head position was 65 dBA.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 10 V/m effective value measured and calculated - at the head
power density 0.265 W/m² effective value measured and calculated - at the head
SAR 0.0015 W/kg average over mass calculated whole body -
SAR 0.0013 W/kg average over mass calculated brain -
SAR 0.0078 W/kg peak value calculated 10 g in the brain
SAR 0.019 W/kg peak value calculated 10 g in the body
Additional parameter details
The exposure level of 10 V/m is relatively high compared to the exposure level in the vicinity of a base station, which is reported to be around 0.01 W/m², or 1.94 V/m [Neubauer et al., 2007].
Measurement and calculation details
The input power level to the antenna was controlled with a fluctuation of less than 1% throughout the experiment. The electric field strength was also monitored using an isotropic electric field probe placed 1.5 m in front of and at the same height as the antenna. Uniformity of the electric field was verified in the area where the subject was seated. The electric field was 9.66 ± 1.64 V/m (rms) within a volume of 0.4 x 0.4 x 0.4 m³, where the head of the subject was expected to be during the experiments. The electromagnetic field and the SAR were simulated using the FDTD method and an adult human body model resembling a Japanese female [Nagaoka et al., 2004] in a sitting position, assuming plane waves. The peak SAR was found at the fingers.
Exposure 2
Main characteristics
Frequency 2.14 GHz
Type
Exposure duration intermittent, 5 min on or off, for 30 min
Modulation
Modulation type cf. additional info
Additional info same as in E1
Exposure setup
Exposure source
Additional info In the intermittent exposure condition, EMF was turned on or off randomly every 5 min. The on/off periods were counterbalanced, such that EMF was on and off for 50% of the time in each subject.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 10 V/m effective value measured and calculated - at the head
power density 0.265 W/m² effective value measured and calculated - at the head
SAR 0.0015 W/kg average over mass calculated whole body -
SAR 0.0013 W/kg average over mass calculated brain -
SAR 0.0078 W/kg peak value calculated 10 g in the brain
SAR 0.019 W/kg peak value calculated 10 g in the body
Reference articles
  • Neubauer G et al. (2007): Feasibility of future epidemiological studies on possible health effects of mobile phone base stations.
  • Regel SJ et al. (2006): UMTS base station-like exposure, well-being, and cognitive performance.
  • Nagaoka T et al. (2004): Development of realistic high-resolution whole-body voxel models of Japanese adult males and females of average height and weight, and application of models to radio-frequency electromagnetic-field dosimetry.
  • Zwamborn APM et al. (2003): Effects of Global Communication system radio-frequency fields on Well Being and Cognitive Functions of human subjects with and without subjective complaints.
Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated material:
Time of investigation:
  • before exposure
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

The group with mobile phone related symptoms did not differ significantly from the controls in their ability to detect exposure to electromagnetic fields. Discomfort and negative mood was significantly greater in the group with mobile phone related symptoms than in the control groups, irrespective of whether the electromagnetic field was actually on or off. The two groups did not differ in their responses to real or sham exposure according to any psychological, cognitive or autonomic measure.
The authors did not find a link between hypersensitivity symptoms and exposure to electromagnetic fields from base stations.
Study character:

Study funded by

  • Committee to Promote Research on the Possible Biological Effects of Electromagnetic Fields, Japan

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