Mobile telephones don’t raise the chance of developing central nervous system cancers, according to a study of Danish mobile-phone subscribers published today in the British Medical Journal.
The study examined reports from Denmark’s centralized cancer registry and subscriber records from mobile-phone networks for 358,403 Danes aged at least 30 from 1990 to 2007. It found no higher incidence of brain tumors or any other cancers in the people studied.
“We didn’t find a higher risk for people subscribing for a mobile phone in the adult population,” said Patrizia Frei, a postdoctoral research fellow at the Swiss Tropical and Public Health Institute in Basel, who led the study while at the Institute of Cancer Epidemiology in Copenhagen, in an interview.
The research is the largest of its type and used data that was already available, instead of retrospectively interviewing phone subscribers whose recall could be selective or unreliable, the scientists said. The findings may help clarify previous research into the link between mobile phones and brain tumors, which the authors said has been inconclusive and, in some cases, criticized for being biased or prone to error.
The International Agency for Research on Cancer, part of the Geneva-based World Health Organization, said in June that mobile phones may cause brain cancer. A month later, the International Commission on Non-Ionizing Radiation Protection’s committee on epidemiology undermined those findings, saying that using the technology may not increase the risk of tumors after reviewing studies from several countries.
More than 5 billion mobile-phone subscriptions are held worldwide, according to the International Telecommunication Union. Concerns have arisen over whether exposing the brain to radiofrequency electromagnetic fields emitted by mobile phones leads to cancer. The IARC said the fields were “possibly” carcinogenic, the same category as diesel fuel and chloroform.
A weakness in the Danish study was that it used data about people who had a mobile-phone contract and excluded corporate accounts. Some non-users of phones may have been counted among the subscribers and some heavy users may not have been included in the study population, wrote Anders Ahlbom, a professor at the Karolinska Institute in Stockholm in an accompanying editorial.
“The absence of a trend in the incidence of brain tumors in national statistics is reassuring,” Ahlbom wrote. “Continued monitoring of health registers and prospective cohorts is warranted.”
The research was funded by the Danish Strategic Research Council.
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