Society News Archive
A new federal study of the potential dangers of cellphone radiation, conducted in rats, found a slight increase in brain tumors in males and raised long-dormant concerns about the safety of spending so much time with cellphones glued to our ears.
But the study had enough strange findings that it has caused other federal scientists to highlight flaws in the research, and experts said these findings and those from other studies continue to suggest the potential risk from cellphone radiation is very small.
The National Institutes of Health study bombarded rats with cellphone radiation from the womb through the first two years of life for nine hours a day. It found tumors in 2 to 3 percent of male rats, which the study's authors called low. But females weren't affected at all and, strangely, the rats not exposed to the cellphone radiation died much faster—at double the rate—of those that were.
The results were preliminary, and only part of what will ultimately be released. They were made public before they were officially published—and despite strong criticism from other NIH scientists—because the results were similar to other studies that hint at a potential problem, said study author John Bucher.
The study is part of a seven-year, $25 million effort conducted by the National Toxicology Program at the request of the Food and Drug Administration. It looked at the specific type of radiation that cellphones transmit, called non-ionizing radiofrequency.
"This is the first study to actually show that non-ionizing radiation (causes) cancer," said Dr. Otis Brawley, the American Cancer Society's chief medical officer. The cancer society in a statement praised the study for "evidence that cellphone signals could potentially impact human health" but notes that it doesn't quite address real risk to people.
"If cellphones cause cancer, they don't cause a lot of cancer," he said in an interview. "It's not as carcinogenic as beef."
He said people should be far more concerned about "distraction caused by cellphone," which he said causes more deaths.
Both Brawley and Bucher said this would not change how they use their own personal cellphones.
While the study found what Bucher called a likely cause of cancer in rats, he cautioned that how that applies to humans "is not currently completely worked out. This may have relevance. It may have no relevance," he said.
Since about 1986, U.S. brain cancer deaths have not increased or decreased, Brawley said. That suggests that whatever effect cellphones may have it is so small as to be undetectable amid regular cases of brain cancer.
Also, Brawley and others point out that cellphone technology has improved so much in recent years to emit less radiation than medical studies simulate. Bucher said the levels the rats were subjected to would be considered "heavy."
Comments by John Moulder1 regarding the preliminary data are:
The report is a fragment of a preliminary version of a much bigger study. It suggests that long duration exposure to high levels of radiofrequency radiation (RFR) might cause a slight increase in brain cancer in male rats. The statistical significance of the result is questionable (that is, it might be noise) and the effect did not occur in female rats and probably not in mice. The implications of this for the safety of mobile phone use is between questionable and nonexistent. Serious evaluation of the health implications of the findings will need to wait for the final report which will be released with "peer review and public comment by the end of 2017."
Items of note are:
1) Both rats and mice were tested, but this report includes only the rats; it is implied (but not clearly stated) that the mouse studies did not find the same glioma increase.
2) Multiple types of tumors were studied, but only data on brain glioma and heart schwannomas are reported; it is implied (but not clearly stated) that results for other tumor types were negative. If all other tumor sites showed no effect, then the statistical and biological significance of the glioma effect is much diminished.
3) Each sex of each species was exposed at 3 different doses. The highest dose (6 Watts/kilogram) and the exposure time (18 hrs/day for 106 weeks starting in utero) were well above what people are exposed to.
4) The higher exposures were thermally significant. That is, they were high enough to cause heat stress in the animals. Since there is some evidence that heat stress may be carcinogenic in its own right (via epigenetic pathways), this makes the results of the higher doses of questionable relevance to human exposure (where RFR-induced heat stress is not an issue if current safety standards are followed).
5) Two different exposure regimens were used (GSM and CDMA-modulated).
6) Survival in the exposed male rats was longer than that in the unexposed group. The cause of this mortality difference is not stated, and this is a critical issue that the final report must address.
7) Four of the six groups of exposed males had higher rates of gliomas than the unexposed males (2–3 tumor per group vs. none in unexposed). This effect was not seen in females (and presumably not in mice?).
8) It is not explicit that the glioma increases in male rats were statistically significant, and it would appear that they are not.
9) Glioma incidence in the unexposed males was lower than that seen historically. If even 1 glioma (and 1–2 were expected) had appeared in the unexposed group, all statistical and biological significance of the results would have vanished.
1John E. Moulder, PhD, is a professor and director of radiation biology, Department of Radiation Oncology, at the Medical College of Wisconsin. Dr. Moulder has lectured on ionizing and nonionizing radiation biology and human health to biologists, physicists, physicians, policy makers, and industry groups around the world and has served as a consultant and expert witness in several cases involving the alleged health effects of exposure to ionizing and nonionizing radiation. Two areas of his research are the biological basis for carcinogenesis and cancer therapy and the biological aspects of human exposure to non-ionizing radiation. Moulder has published extensively in these areas, and his research has been supported by the National Institutes of Health and the American Cancer Society.