Study type: Medical/biological study (experimental study)

Effects of GSM-900 microwaves on DMBA-induced mammary gland tumors in female Sprague-Dawley rats. med./bio.

Published in: Radiat Res 2003; 160 (4): 492-497

Aim of study (acc. to author)

(1) To test the hypothesis that sub-chronic whole-body exposure to GSM (global system for mobile communication) 900 microwaves had an effect on tumor promotion and tumor progression and (2) to look for a threshold for the effect in the SAR range from 0.1 to 3.5 W/kg.

Background/further details

Mammary tumors were induced by ingestion of a single dose of 7,12-dimethylbenzanthracene (DMBA, 10 mg) in female rats.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: repeated daily exposure, 2 h/day, 5 days/week for 9 weeks
  • SAR: 3.5 W/kg spatial average (whole body)
  • SAR: 2.2 W/kg spatial average (whole body)
  • SAR: 1.4 W/kg spatial average (whole body) (Experiment 1 + 2)
  • SAR: 0.7 W/kg spatial average (whole body)
  • SAR: 0.1 W/kg spatial average (whole body)

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Charakteristic
Exposure duration repeated daily exposure, 2 h/day, 5 days/week for 9 weeks
Additional info plane wave
Modulation
Modulation type pulsed
Exposure setup
Exposure source
Distance between exposed object and exposure source 1.8 m
Chamber Two identical anechoic chambers (3 m x 3 m x 3 m) were used, one with a base station antenna above the cages and another one for sham exposure.
Setup The animal cages of Plexiglas were divided into 20 separate compartments (6 cm x 6 cm x 17 cm) in two rows that kept the animals parallel to the electric field. Gel phantoms were placed in the 4 outermost compartments in order to provide uniform exposure for the 16 rats.
Additional info In each of the two experiments, the rats were divided into five groups: three groups exposed at different levels, one sham-exposed group, and another untreated cage control group.
Parameters
Measurand Value Type Method Mass Remarks
SAR 3.5 W/kg spatial average measured whole body -
SAR 2.2 W/kg spatial average measured whole body -
SAR 1.4 W/kg spatial average measured whole body Experiment 1 + 2
SAR 0.7 W/kg spatial average measured whole body -
SAR 0.1 W/kg spatial average measured whole body -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

The findings are negative in terms of latency, multiplicity and tumor volume. With regard to tumor incidence, there was an increase in the rate of incidence at 1.4 W/kg but less at 2.2 W/kg and none at 3.5 W/kg. A trend toward a reduction of malignant tumor incidence and multiplicity was found at the lowest SAR level with a concomitant increase in benign tumor multiplicity.
Overall, these data, which are rather inconsistent, do not bring new evidence of a co-promoting effect of exposure to GSM-900 signals using the DMBA rat model.

Study character:

Study funded by

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