• 12/10/2006
  • Bethesda, MD
  • Katherine Hobson
  • US News (www.usnews.com)

A big, new comprehensive study should provide some comfort to those still worried about a connection between cancer and cellphones: It finds no link and provides more evidence that electromagnetic fields from the phones do not cause tumors of the head and neck.

The study, published in the current Journal of the National Cancer Institute (an independent publication no longer associated with the NCI), looked at cellphone records from more than 420,000 people in Denmark who began using the phones between 1982 and 1995. Relying on the country’s national cancer registry, researchers looked at cancer cases through 2002 among the cellphone users and the overall population.

The results? There was no increased risk of tumors in the brain, salivary glands, eyes, or inner ear. Nor was there a heightened risk of leukemia. In fact, the risk of cancer was slightly less in cellphone users, something lead author Joachim Schuz, head of biostatistics and epidemiology at the Institute of Cancer Epidemiology at the Danish Cancer Center, can’t explain but says might be because of chance alone. Early cellphone users might also differ socioeconomically from nonusers in a way that might affect cancer risk, he says. (For example, professional males with high incomes–typical for early adopters of new technology–might have healthier lifestyles.)

“We think it’s a very strong study,” he says. The findings build on the researchers’ earlier study looking at the same group, which also found no link but only tracked cellphone users until 1996. Since cancer can take years to develop, it’s important to keep monitoring the health of the earliest users to see if any association to cancer emerges later. In addition to that follow-up, Schuz and his fellow researchers are also studying children and young adults–an important population to research, given that so many kids start using cellphones at such a young age.

Because cellphones emit electromagnetic fields that can penetrate the human brain, there’s been concern that users might be at risk of cancer or other diseases. “If everyone is using a mobile phone, even a small increase in risk could have a big effect,” says Schuz. But according to the American Cancer Society, of 16 earlier studies looking at cancer and cellphone use, just two have found some kind of link. Those studies were not as well designed as the ones showing no link, the ACS said.

The new study is large, covers a lot of people over a long period of time, and uses phone records rather than relying on people to recall past cellphone use–all pluses–but has a few limitations. People whose cellphones were in their companies’ or employers’ names were excluded; that might be significant because business users might have also been the heaviest users. Also, anyone who started using a cellphone after 1995 was not included, whereas the general population comparison group included people who started using cellphones after that year. Researchers said this shouldn’t skew the study, since brain tumors take a long time to develop.

This study received no funding from the cellphone industry.