(Bloomberg) – Research in rats is re-igniting the long-running debate over whether mobile-phone use can cause cancer.
Two types of tumors — one in the brain, one in the heart — were spotted in some male rats exposed to radiofrequency radiation at levels used by the U.S. telecommunications industry, according to a 74-page report on partial findings from the U.S. government-funded study. The study follows a flurry of reports published in 2011 that confused more than clarified the cancer risk faced by the world’s billions of mobile-phone users.
“These findings appear to support the International Agency for Research on Cancer conclusions regarding the possible carcinogenic potential of radiofrequency radiation,” the researchers wrote in the report. “Given the widespread global usage of mobile communications among users of all ages, even a very small increase in the incidence of disease resulting from exposure to RFR could have broad implications for public health.”
The results from the National Toxicology Program study weren’t formally peer-reviewed and published by a scientific journal. Instead, they were posted on a website that allows researchers to share raw and unvetted material.
The low incidence of cancer observed in the rats in the U.S. government study were likely the result of whole-body exposure to the radiation, and was similar to tumors seen in some studies of mobile-phone use, the researchers said. They had higher confidence in the link between the radiation and the heart tumors. Cancer only appeared in male rats, with no significant effects seen in females.
The rats exposed to radiation also lived longer than those who weren’t, an unexpected finding that suggests cancer may have developed simply because those rats were older. The research will be completed in the second half of next year, with draft reports available for review and comment by the end of 2017.
“The results do not appear consistent with the cancer rates within the human population, nor with the majority of other experimental research, even at the very high exposure levels, which are many times higher than humans are exposed to,” Rodney Croft, director of the Australian Centre for Electromagnetic Bioeffects Research, said in an e-mailed statement on Friday.
The International Agency for Research on Cancer, part of the World Health Organization, said in 2011 that the devices may cause brain cancer in humans, citing a review of studies. The agency classified mobile phones as “possibly” cancer-causing — the same category as coffee, ginkgo biloba extract, dry cleaning and engine exhaust.
A month later, the International Commission on Non-Ionizing Radiation Protection’s committee on epidemiology undermined those findings. After reviewing studies from several countries, the commission said that using the technology may not increase the risk of tumors.
A few months later, a Danish study in people found mobile phones don’t pose additional danger. The research is the largest of its type and used data that were already available, instead of retrospectively interviewing phone subscribers whose recall could be selective or unreliable.
The Federal Communications Commission said it was aware of the National Toxicology Program’s ongoing research on radiofrequency radiation levels.
“We will continue to follow all recommendations from federal health and safety experts including whether the FCC should modify its current policies and RF exposure limits,” said Neil Grace, an FCC spokesman. “Scientific evidence always informs FCC rules on this matter.”