The findings of a new government study have highlighted the growing concerns about the link between cancer and cellphone usage, indicating that male rats may be more likely to develop tumors following exposure to radio frequencies commonly associated with mobile communication.
Researchers with the government-funded National Toxicology Program (NTP), a division of the National Institutes of Health (NIH), report that rats exposed to radio frequencies like those radiated by cell phones showed an increased risk of two types of tumors. Partial findings of the study were published on May 26 online in BioRxiv Beta, a server for biology research.
During the multi-year study, which has been underway for more than a decade, researchers tested 2,500 rodents who were exposed to cell phone radiation for nine hours every day for two years. At $25 million, it is the most expensive study the NTP has ever performed.
The studt found increased incidence of two types of tumors, known as gliomas. One type involved gial cells in the brain, and another involved schwannomas of the heart.
The NIH is reviewing the findings, but has noted that observational data on humans have found limited evidence of cell phone cancer risks.
The study is the latest in an ongoing scientific and medical debate about whether the electromagnetic fields given off by mobile devices can cause brain cancer.
While some studies have found no links between brain cancer and the use of cell phones and other mobile devices, a number of others appear to show evidence that there is a connection.
In May 2011, the World Health Organization (WHO) announced that it was classifying radiofrequency electromagnetic fields emitted by wireless phones as a possible carcinogen. Similar to this latest study, a working group of 31 scientists from around the world determined that cell phone emissions appeared to be linked to an increased risk of glioma.
However, a study released a little more than a month later by Danish researchers found no link between cell phones and brain tumors.
In May 2014, French researchers found a link between heavy cell phone use and brain cancer. Cell phone users with the longest cumulative duration of calls, 896 hours of talk time or more, were twice as likely to develop brain tumors than those who talked less.
In November 2014, Swedish researchers reported that people who use mobile phones regularly for more than 25 years have an increased risk of glioma of the brain, similar to the tumors found in the rats. That study found that cell phone radiation exposure was linked to a 30% increased risk of brain tumors overall, but at the 25 year point the risk had grown to 300%. However, even at that level, the overall chance of developing glioma was only 0.016%.
In 2013, the Federal Communications Commission (FCC) announced that it was reassessing the potential effects of radiation exposure from cell phones and mobile devices. The FCC plans to look at radiation exposure and determine how much is emitted by the devices and how those emissions affect humans.
In the meantime, experts recommend users attempt to reduce their risk by using headsets or speakerphones when possible, holding the phone away from the body, and texting instead of calling as often as possible. Some also recommend only using the phone when it has a strong signal.