Danish researchers can offer some reassurance if you’re concerned about your cellphone: Don’t worry. Your device is probably safe.
The biggest study ever to examine the possible connection between cellphones and cancer found no evidence of any link, suggesting that billions of people who are rarely more than a few inches from their phones have no special health concerns.
The Danish study of more than 350,000 people concluded there was no difference in cancer rates between people who had used a cellphone for about a decade and those who did not.
Last year, a separate large study found no clear connection between cellphones and cancer. But it showed a hint of a possible association between very heavy phone use and glioma, a rare but often deadly form of brain tumor. However, the numbers of heavy users was not sufficient to make the case.
Two U.S. agencies – the Food and Drug Administration and the Federal Communications Commission – have found no evidence that cellphones are linked to cancer.
Yet fears of a link persist, despite the fact that cancer rates have not risen since cellphones were introduced.
In the latest research, published online Thursday in the journal BMJ, researchers updated a previous study examining 358,403 cellphone users aged 30 and over in Denmark from 1990 to 2007. They found cellphone users did not have a higher cancer risk compared with those without cellphones.
Cancer rates in people who used cellphones for about 10 years were similar to rates in people without a cellphone. Cellphone users were also no more likely to get a tumor in the part of the brain closest to where phones are usually held against the head.
The study was paid for by the government’s Danish Strategic Research Council.
About three-quarters of the world’s population, more than 5 billion people, use a cellphone. That makes it difficult for scientists to compare cancer incidence in people who use the devices versus those who do not.
Cellphones send signals to nearby towers via radio waves, a form of energy similar to microwaves. But the radiation produced by cellphones cannot directly damage DNA and is different from stronger types of radiation like X-rays or ultraviolet light. At very high levels, radio frequency waves from cellphones can heat up body tissue, but that is not believed to damage human cells.