Years of research have still not reached a conclusion on whether or not cellphones cause cancer. But on Friday, two government studies suggest that if indeed there is any risk, it would be small.
There have been countless questions about the safety of cellphones, drawing intense debates for years as the devices have become inseparable from people in recent years, the New York Times reports. The two studies, one in rats and one in mice, looked at the effects of the type of radiation cellphones emit over the past ten years. The $25 million research works are now considered the most extensive.
In male rats, there was a link between heart tumors and high exposure to cellphone radiation. But this was not visible in female rats, or in mice. The rodents were exposed to radiation nine hours a day for two years, much more than what people experience even with heavy cellphone use. Therefore, the results may not be applied directly to humans, according to John Bucher, a senior scientist at the National Toxicology Program.
These results have not led to Bucher’s changing his cellphone habits, but he did note that the heart tumors in rats, malignant schwannomas, are similar to acoustic neuromas, or benign tumors in people in the area of the nerve connecting the ear to the brain. Some studies have linked this to cellphone use.
Close to 20 animal studies have been conducted, “with the vast majority coming up negative with respect to cancer. Bucher added that other agencies are studying cellphone use in people and its links to cancer.
The Food and Drug Administration, for its part, says that it respects the research and had reviewed other studies on cellphone safety, but had “not found sufficient evidence that there are adverse health effects in humans caused by exposures at or under the current radio-frequency exposure limits.”
Dr. Jeffrey Shuren, director of the F.D.A.’s center for devices and radiological health, said, “Even with frequent daily use by the vast majority of adults, we have not seen an increase in events like brain tumors.”