Nov 21, 2017
Two-year oncogenicity evaluations of cell phone radiofrequency radiation in Sprague-Dawley rats and B6C3F1 mice
McCormick D. Two-year oncogenicity evaluations of cell phone radiofrequency radiation in Sprague-Dawley rats and B6C3F1 mice. Toxicology Letters. 280 (Suppl. 1): S31. Oct 20, 2017. https://doi.org/10.1016/j.toxlet.2017.07.07
Epidemiology data concerning possible health effects of exposure to radiofrequency fields (RF) are conflicting. For this reason, well-designed and controlled studies in predictive laboratory animal models provide the best prospective opportunity to identify effects of RF exposure that may translate into human health hazards.
The U.S. National Toxicology Program supported a program in our laboratory to identify and characterize effects of acute, subchronic, and chronic exposure to non-thermal levels of RF in Sprague-Dawley rats and B6C3F1 mice.
Five-day pilot studies were performed to identify the maximum Specific Absorption Ratios (SARs) to which juvenile, adult, and pregnant rodents can be exposed without increasing body temperature by >1.0 °C.
Subsequent subchronic (ten-week) toxicity studies failed to identify any toxicologically significant effects of non-thermal RF on survival, body weight, clinical signs, hematology, or gross or microscopic pathology.
Two-year studies were performed to determine if exposure to non-thermal levels of RF increases the incidence of neoplasia in any site. Male rats exposed to RF demonstrated significantly increased incidences of glioma (brain) and schwannoma (heart); these increases were not seen in female rats or in either sex of mice.
Gliomas and schwannomas have been identified in some epidemiology studies as possible RF-induced neoplasms. Considering (a) the conflicting results of RF epidemiology studies and (b) the lack of generally accepted biophysical or molecular mechanisms through which RF could induce or promote neoplasia, data from animal bioassays will play a central role in “weight-of-the-evidence” assessments of the possible health effects of RF exposure.
Sep 20, 2017
Scientists from the National Toxicology Program presented their data on the genotoxicity of cell phone radiation in rats and mice at the annual meeting of the Environmental Mutagenesis and Genomics Society held in Raleigh, North Carolina from September 9-13, 2017.
Male and female rats and mice were exposed to 2G cell phone radiation, either CDMA or GSM, for 18 hours per day in 10 minute intervals. The rats were exposed to cell phone radiation at 1.5, 3, or 6 W/kg specific absorption rate (SAR) for 19 weeks from gestation day 5. The mice were exposed to radiation at 2.5, 5, or 10 W/kg SAR for 13 weeks from postnatal day 5.
DNA damage was assessed in three brain regions, in liver cells and in blood leukocytes using the comet assay. Chromosomal damage was assessed in peripheral blood erythrocytes using the micronucleus assay.
DNA damage was significantly increased:
- in the frontal cortex of male mice from either CDMA or GSM cell phone radiation exposure,
- in peripheral leukocytes of female mice from CDMA exposure, and
- in the hippocampus of male rats from CDMA exposure.
There were no significant increases in micronucleated red blood cells in rats or mice.
The authors concluded that, “exposure to RFR [radio frequency radiation] has the potential to induce measurable DNA damage under certain exposure conditions.”
The NTP is scheduled to publish a complete report about its cell phone radiation studies in early 2018. The FDA called for this research in 1999.
Here is the abstract for this presentation.