Shirai T, Kawabe M, Ichihara T, Fujiwara O, et al. (2005).
This was a long-term study of the effect of exposure to electromagnetic fields (EMF) on rats. The authors studied the offspring of rats who had been injected with N-ethylnitrosurea (ENU) while pregnant. ENU promotes brain tumour development in rats.
Five groups were studied, with 50 males and 50 females in each. Group 1 had no ENU exposure and no other treatment, and was a control group. The ENU-exposed pups were allocated to 4 groups. Group 2 received ENU alone and was kept in cages throughout. Group 3 was placed in exposure groups but received no EMF exposure. Group 4 was exposed to EMF at SAR 0f 0.67 W/kg, and Group5 at SAR 2.0 W/kg. The EMF was emitted at 1,439 MHz frequency, and was a TDMA signal for the Personal Digital Cellular (PDC) standard Japanese cellular system. The EMF exposure was started at 5 weeks of age, and was given for 90 minutes a day, 5 days a week for 104 weeks, or until death. The whole-body average SAR was estimated as less than 0.4 W/kg. Blood was obtained from a sample of each group just before the end of the experiment for measurement of levels of cortisone, melatonin, and adrenocorticotrophic hormones. Autopsies were done at the conclusion of the study, or at death in those who died early.
There were no inter-group differences in body weight, food consumption, and survival rates. There was no difference in the incidences per group of brain and/or spinal cord tumours in the EMF-exposed groups. No clear changes in tumour types were observed. The blood hormone tests showed no significant alteration.
The authors conclude: