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Why You Still Shouldn't Worry About Cellphones And Cancer

This article is more than 10 years old.

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The news that an arm of the World Health Organization said cellphones might cause cancer seems to have caused a World Wide Web freakout. But what kind of risks are we talking about? The reality is calming.

Let's do some math. The WHO said that the classification was mainly due to a study that showed heavy cellphone use might cause a 40% increased risk of glioma, a type of brain tumor. There are 22,000 cases of brain cancer in the U.S. annually, and a spokesman for the American Cancer Society tells me that 30%, or about 8,000, are glioma.*

Now, 96% of the U.S. population, or about 300 million people, have cellphones. If everyone's risk of glioma went up 40% as a result of cellphone use, the number of gliomas in the U.S. would increase by 3,000. That's a one in 100,000 increase in each person's risk of glioma, which still isn't very big.

But the study the WHO is citing only showed the 40% increase in the 10% of people who used cellphones most. I don't know how many people in the U.S. would now fall into this group, but we'd be talking about maybe hundreds of cases spread out over the whole U.S. population.

If that still sounds scary, compare it to another cancer – one that I do find frightening. The number of cases of throat cancer caused by the human papilloma virus (HPV) is estimated to be about 11,300 now, increasing to 20,000 and beyond over the next few years as this infection spreads. That's a far scarier increase than if the glioma link for cellphones is true and everybody in the U.S. is talking on their phones nonstop. If we're going to worry about cellphones, we should worry about vaccinating boys for HPV.

And there really is no certainty about the cellphone-glioma link. The largest study of cellphone use and brain cancer, INTERPHONE, found a statistically significant 40% increase in glioma rates among heavy cellphone users, that's true. But the paper doesn't so much provide that firm number as a range of possibility – called a confidence interval by scientists – of between 3% and 89%. This is a risk that can't quite be ruled out, not one that we've quantified.

Cellphones are still a relatively new technology, but you might expect we'd be seeing an increase in the number of gliomas caused by them. But the rate of glioma over the past 35 years has actually remained pretty much flat, and actually decreased slightly, according to Otis Brawley, the chief medical officer of the American Cancer Society. Brawley also notes that the category the WHO put cellphones in includes DDT, coffee, and pickled vegetables. (Yes coffee has been shown to reduce risk of some cancers, too. I drink it because it makes me happy. I also like pickles, and my Droid phone.)

If there is a reason to care about this data, it's this: if there is any risk of glioma, you could probably avoid it by using an earpiece or speaker phone for long cellphone conversations, and we could encourage cellphone manufacturers like Apple, Motorola, and Nokia to design their phones to help people do that. Glioma is a terrible cancer, and if we could reduce the number of cases through simple means it would be worth it.

But cellphones also improve our lives in numerous ways, and the evidence of risk just doesn't warrant much change. We could probably improve our health a lot more by avoiding charred meats, wearing sunscreen, eating vegetables, and helping people quit smoking. The cellphone cancer story just isn't that scary – it's barely even a pickle.

*Correction: I previously wrote that 80% of brain cancers are glioma. That's wrong. Eighty percent of *maliginant* brain cancers are glioma. About a third of all brain cancers are gliomas, per this American Cancer Society press release. Thanks to Geoff Curtis at WeissCom for pointing this out. I've made appropriate changes throughout the post. This makes the risk even less scary.