Using mobile phones may not increase the risk of brain cancer, according to a new analysis of scientific evidence published a month after a World Health Organization agency said the technology may cause tumors.
Studies from several countries have failed to show an increase in brain tumors as many as 20 years after mobile phones were introduced and 10 years after the technology became widespread, the International Commission on Non-Ionizing Radiation Protection’s committee on epidemiology wrote in Environmental Health Perspectives, a monthly journal of the U.S. National Institute of Environmental Sciences.
The findings undermine those of an International Agency for Research on Cancer review. Concerns that the technology might be harmful to the health of the 4.6 billion people who use cell phones aren’t likely to be put to rest soon, because data is limited and researchers can’t prove the complete absence of an impact, the panel said.
“This is a really difficult issue to research,” David Spiegelhalter, the University of Cambridge’s Winton professor of the public understanding of risk, said in an e-mailed statement. “Even given the limitations of the evidence, this report is clear that any risk appears to be so small that it is very hard to detect, even in the masses of people now using mobile phones.”
The committee included scientists from the U.K., Sweden, Australia and the U.S. The International Commission on Non- Ionizing Radiation Protection sets guidelines for exposure limits to radiation including radio-frequency fields emitted by mobile phones.
The panel reviewed all published studies that have examined the potential link between mobile-phone use and brain tumors, including the largest epidemiological study to date, known as Interphone. Anthony Swerdlow, a professor of epidemiology at the Institute of Cancer Research in London who led the review, also oversaw one of the U.K. teams involved in the Interphone study, which was published last year and failed to find a definite link between mobile-phone use and certain types of brain tumors.
Other studies in people and animals, along with trends in the incidence of brain tumors, suggest no increase in the risk, although the possibility can’t be ruled out, Swerdlow said in a statement.
Exposure to radiofrequency electromagnetic fields from handsets is greater than that from phone towers and base stations, the International Agency for Research on Cancer, part of the Geneva-based WHO, said in June. The fields are “possibly” carcinogenic, the same category as diesel fuel, chloroform and working as a firefighter, according to the IARC, based in Lyon, France, which classifies cancer risks.
The IARC didn’t issue guidelines for cell-phone use and said more study is needed, after finding some evidence for an increased risk of glioma, or brain cancer.
“If there are no apparent effects on trends in the next few years, after almost universal exposure to mobile phones in Western countries, it will become increasingly implausible that there is a material causal effect,” Swerdlow said. “If there are unexplained rising trends, there will be a case to answer.”
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