Study type: Medical/biological study (experimental study)

Report of final results regarding brain and heart tumors in Sprague-Dawley rats exposed from prenatal life until natural death to mobile phone radiofrequency field representative of a 1.8 GHz GSM base station environmental emission. med./bio.

Published in: Environ Res 2018; 165: 496-503

Aim of study (acc. to author)

To evaluate the possible carcinogenic effects of livelong far field exposure to 1.8 GHz electromagnetic fields in the heart and brain of rats.

Background/further details

This is so far the largest long-term study ever performed in rats on the health effects of radiofrequency fields, including 2,448 animals. The study can be regarded as complementary to the long-term study conducted by the NTP (NTP, 2018), which used near field exposure and significantly higher field strengths. In this article, only the partial results for heart and brain are presented, further results will be published in the future.
Four groups of rats were examined: 1) exposure to 5 V/m (male n=401, female n=410), 2) exposure to 25 V/m (male n=209, female n=202), 3) exposure to 50 V/m (male n=207, female n=202), 4) sham exposure (male n=412, female n=405).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1,835 MHz
Exposure duration: 19 h/day, 7 days/week from 12th day of gestation until natural death (up to 152 weeks)
Exposure 2: 1,835 MHz
Exposure duration: 19 h/day, 7 days/week from 12th day of gestation until natural death (up to 152 weeks)
Exposure 3: 1,835 MHz
Exposure duration: 19 h/day, 7 days/week from 12th day of gestation until natural death (up to 152 weeks)

Exposure 1

Main characteristics
Frequency 1,835 MHz
Type
Charakteristic
Exposure duration 19 h/day, 7 days/week from 12th day of gestation until natural death (up to 152 weeks)
Modulation
Modulation type cf. additional info
Additional info

modulated in GMSK mode, in calI operating mode and with the complete time slot assignment

Exposure setup
Exposure source
Chamber rats of each group were located in separate rooms with the same environmental conditions (i.e., temperature of 22 ± 3°C, a relative humidity of 40–60% and 12 h/day homogeneous illumination); rooms were totally shielded with RF absorbing material and ensured a minimum insulation of 30 dB; 5 rats were housed in one polycarbonate cage, respectively
Setup each single exposure device served at least 400 rats; rat cages were located in wooden circular-shaped devices on several levels up to a height of about 1.6 m; each level formed a ring at a distance of about 2 m from the antenna in the center; a collinear antenna (a phased array of stacked dipoles) was able to transmit a homogeneous far field with cylindrical distribution of the field strength (field uniformity better than 3 dB); the output levels were controlled with a closed loop control system, able to stabilize the field in an uncertainty level of 1 dB range
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 5 V/m - measured - -
SAR 0.001 W/kg - estimated whole body -
power density 0.07 mW/cm² - estimated - -

Exposure 2

Main characteristics
Frequency 1,835 MHz
Type
Charakteristic
Exposure duration 19 h/day, 7 days/week from 12th day of gestation until natural death (up to 152 weeks)
Modulation
Modulation type cf. additional info
Additional info

modulated in GMSK mode, in calI operating mode and with the complete time slot assignment

Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 25 V/m - measured - -
SAR 0.03 W/kg - estimated whole body -
power density 0.17 mW/cm² - estimated - -

Exposure 3

Main characteristics
Frequency 1,835 MHz
Type
Charakteristic
Exposure duration 19 h/day, 7 days/week from 12th day of gestation until natural death (up to 152 weeks)
Modulation
Modulation type cf. additional info
Additional info

modulated in GMSK mode, in calI operating mode and with the complete time slot assignment

Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 50 V/m - measured - -
SAR 0.1 W/kg - estimated whole body -
power density 0.66 mW/cm² - estimated - -

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)

A statistically significant increase in the incidence of heart schwannomas was observed in male rats exposed to a electromagnetic field of 50 V/m (group 3) compared to the sham exposure group. Moreover, an increase in the incidence of heart Schwann cells hyperplasia in male and female rats of group 3 and malignant glial tumors of the brain in female rats of group 3 was observed in comparison to the sham exposure but was not statistically significant.
No differences were found in mean food and water consumption, body weight or survival rate, either in male or in female rats, between the groups.
The authors conclude that livelong far field exposure to 1.8 GHz electromagnetic fields could increase the incidence of tumors in the heart and possibly also in the brain of rats. These results are consistent with and reinforce the results of the NTP study on near field exposure.

Study character:

Study funded by

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