Swedes who talked on mobile or cordless phones for more than 25 years had triple the risk of a certain kind of brain cancer compared to those who used wireless phones for less than a year, a new study suggests.
The odds of developing glioma, an often deadly brain cancer, rose with years and hours of use, researchers reported in the journal Pathophysiology.
“The risk is three times higher after 25 years of use. We can see this clearly,” lead researcher Dr. Lennart Hardell told Reuters Health in a telephone interview.
His finding contrasts with the largest-ever study on the topic – the international Interphone study, which was conducted by the International Agency for Research on Cancer and funded in part by cell phone companies. That study, published in 2010, failed to find strong evidence that mobile phones increased the risk of brain tumors.
Even if the odds of developing a glioma were doubled or tripled, however, the risk would still remain low.
A little more than 5 out of 100,000 Europeans (or 0.005 percent) were diagnosed with any kind of malignant brain tumor between 1995 and 2002, according to a 2012 study in the European Journal of Cancer (http://bit.ly/1xIlQam). If the rate triples, the odds rise to about 16 out of 100,000 (or 0.016 percent).
Hardell, an oncologist from University Hospital in Orebro, Sweden, and his colleague Michael Carlberg matched 1,380 patients with malignant brain tumors to people without such tumors and compared their wireless phone use.
People who reported using wireless phones for 20 to 25 years were nearly twice as likely to be diagnosed with glioma as those who reported using them for less than a year, the study found. Those who used cell and cordless phones for more than 25 years were three times more likely to develop one of these tumors.
The study did not show an association of wireless phones with malignant brain tumors other than glioma.
Participants who recalled talking the most – more than 1,486 hours – on wireless phones were twice as likely to develop glioma compared to those who said they used the devices the fewest hours – between one and 122 hours, the study found.