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Interphone study on mobile phone use and brain cancer risk: No clear answers

A 10 year study of cell phones and brain tumours cannot conclusively say if usage poses any serious health risks. The Interphone Study took 10 years and 25-million-dollars to complete. It involved 50 researchers in 13 countries including Canada, a combined population of 488 million people. The results were recently published in the International Journal of Epidemiology. The study was coordinated by the World Health Organization’s International Agency for Research on Cancer (IARC).

The Interphone study looked at cancer patients and worked backward to establish cell phone habits. It is the largest study of cell phones and cancer ever done and included 2,708 cases of glioma and 2,409 of meningioma, another type of brain tumor, with a total of over 5,634 controls —from 13 countries. Eligible cases were patients diagnosed between 2000 and 2004. (Meningioma was not linked to cell phone use.) The total budget of the study, which got underway in 2000, was €19.2 million (~US$25 million). Funding came from the European Commission (€3.74 million) and the cell phone industry (€5.5 million), as well as other sources.

Everyone anticipated that Interphone wouldn’t offer any definitive findings, and they were right. “An increased risk of brain cancer [has not been] established,” said Christopher Wild, the director of the IARC.

But, there are “suggestions of an increased risk” at “the highest exposure levels,” according to the abstract of the paper published by the International Journal of Epidemiology.

How should those “suggestions” be interpreted?

At the very least, the risks are greater than many believed only a few years ago. In a series of interviews, a number of the members of the Interphone project told Microwave News that they now see the risk among long-term users as being larger than when the study began. Some think the risk warrants serious attention.

“To me, there’s certainly smoke there,” said Elisabeth Cardis, who leads the Interphone project. “Overall, my opinion is that the results show a real effect.” Cardis is with the Center for Research in Environmental Epidemiology (CREAL) in Barcelona. She moved there two years ago after working on Interphone at IARC for close to a decade.

“There is evidence that there may be a risk; Interphone has made that a little stronger,” said Bruce Armstrong of the University of Sydney, another member of Interphone. “It shows some indication of an increased risk of gliomas, but I cannot say this with certainty.” (A glioma is a type of brain tumor.)

Sigal Sadetzki, the Israeli member of Interphone, goes further. She pointed out that while the risks are inconclusive, a number of the results show some consistency. These include increased risks among the heaviest users, the fact that the risks were highest on the side of the head the phone was usually used and that the tumors were in the temporal lobe of the brain, which is closest to the ear. Sadetzki is with the Gertner Institute outside Tel-Aviv. “The data are not strong enough for a causal interpretation, but they are sufficient to support precautionary policies,” she said.

There are, of course, dissenting voices saying that the use of mobile phones for over ten years shows no increased risk of brain tumors.

One of the major criticisms leveled at the study is that it mostly collected data on cell phone usage between years 2000 and 2004, when people didn’t use their cell phones as much as they do today. An average study participant talked on the phone for two to 2-1/2 hours a month (not more than 30 minutes a week).
Today, though, the average cell phone user in Canada and the U.S. talks that much in a week, with cumulative totals more like 10 hours a month.

So, who to believe and what to do?
First, consider research done by Henry Lai, a biologist at the University of Washington: Only 25% of studies funded by the wireless industry show some type of biological effect from microwave radiation. Independently funded studies, however, are far more damning: 75% of those studies — free of industry influence — show a bioeffect. Some 30% of funding for the Interphone research was provided by industry, which critics say has resulted in a favorable skewing of some Interphone data.

Obviously, we need to demand more independent research into microwave radiation. In the meantime, we should also treat cellphones and other wireless gadgets with less adoration and more suspicion, and as individuals we may want to follow the lead of many nations and regulate the way we use them for ourselves.

For example, Belgium, France, Finland, Germany, Russia and Israel have publicly discouraged use of cellphones by children. (Independent research in Sweden last year concluded there was an astonishing 420% increased chance of getting brain cancer for cellphone users who were teenagers or younger when they first started using their phones.) France has gone so far as to issue a generalized national cellphone health warning, banned cellphones in elementary schools and considered outlawing marketing the phones to children.

The personal equivalent? For starters, don’t get rid of your land line. Buy a hands-free device; keep your cellphone away from your head, face and neck. Don’t carry it in your pocket for hours on end (there’s some evidence cellphones aren’t good for your sperm count).

And when it comes to children, don’t forget that their skulls are way thinner and the brain smaller so radiation absorption is much higher. It’s best to not allow small children the use of a mobile phone; encourage them to text instead of talking on the handset.

It’s only common sense to do what you can to take yourself out of the guinea pig pool.

For more information:

Interphone study reports on mobile phone use and brain cancer risk
International Agency for Research on Cancer (May 10, 2010)

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