ScienceSkepticism

Cell Phones & Brain Cancer: An Announcement by the WHO

Today the International Agency for Research on Cancer (IARC), a part of the World Health Organization (WHO), announced that cell phone use may be carcinogenic to humans. After a week-long meeting in France, during which 31 scientists from 14 countries reviewed the available data, the group assigned radiofrequency EMF a “2B” classification. Prior to today’s announcement, the WHO’s position was that no adverse health effects had been established.

This does not mean that cell phone use causes cancer, only that the IARC’s position is that the available data is insufficient and further research is needed.

2B is the mid-level classification, and it only means that it’s “possibly” carcinogenic. Here are the classes:

Other items in the 2B category are lead, engine exhaust, and chloroform.

The IARC seems to have based their assessment largely on a study that showed a 40% increase in glioma (a malignant brain tumor) in high-volume (30 minutes per day) long-term (10 years) users. The study in question has been the subject of criticism for various reasons including the self-reported frequency of cell phone use. The IARC considers the existing data correllating cell phone use to glioma and acoustic neuroma “limited”, but is urging further research into a possible connection. IARC Director Christopher Wild said:

“it is important that additional research be conducted into the long-term, heavy use of mobile phones. Pending the availability of such information, it is important to take pragmatic measures to reduce exposure such as hands-free devices or texting.”

Critics of the announcement point out that the incidence of brain cancer hasn’t risen since cell phone use became popular, and that there’s no known biological mechanism to explain how cell phone use could cause cancer. This blog post is an excellent, thorough critique of the issue.

Taking action based on this announcement is a cautious measure: there’s not enough data to show cell phone use causes cancer, but there’s also not enough to show that it’s safe. Be sure to put it in perspective and focus on known health risk such as smoking or being overweight, if applicable, before focusing on precautionary measures.

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15 Comments

  1. Yes, and cue the magic-battery-sticker sellers quote mining this to hell and back. “WHO says cell phones cause brain cancer!”

    It’s be nice if there was a clearer way to communicate stuff like this, but I can’t think of one without sacrificing accuracy.

  2. They’ve looked at the same data that we already know about and been insanely cautious. The media then translates “maybe, at least we can’t rule it out without further research” into “get rid of your cell phone now!”.
    A better headline would be “People with brain cancer are more likely to report they used to talk on their cell phone really, really often. Duh!”

  3. This to me looks like a prime example of something that is evidence based, but not science based.
    Sure, there is evidence that links the two phenomena, but there’s no scientific reason why. Nor is the link sufficiently clear to suggest looking for a scientific reason.
    And everything we know about radiation suggests there is no link.

  4. I’m having trouble following their chain of reasoning. They’ve found a correlation between heavy cell phone use and increased incidence of cancer. From that, they’ve concluded that the cause is the radio emissions from the phones. But I didn’t see anything in the IARC monograph that would justify that conclusion.

    I see where the monograph indicates they looked at occupational and environmental exposures to radio waves but determined the evidence from those studies to be inadequate. Wouldn’t that point to a factor other than radio emissions being the culprit, then?

    There are a lot of materials that go into a cell phone, some of which become volatile when heated. Maybe someone should do a comparison of cell phone exposure to, say, exposure to a warmed-up chunk of ABS plastic treated with a flame retardant. Of course, a lot of newer phones use metal cases instead of ABS, so it’s hard to say what you’d get out of that study.

  5. I still fail to understand, if Cell Phones give you cancer, why would they primarily give you brain cancer? Wouldn’t they also affect your gonads, bladder, colon, and all the other yummy things near your pants pockets? Why don’t researchers check those out?

    1. Two reasons. 1) Usually, when the phone is in your pocket, it isn’t transmitting. Cell phones check in with the nearest tower once in a while (for a second or two every few minutes), so that incoming calls can be routed to them, but mostly when not in use, they are just receivers, which emit much less RF than when transmitting. Usually, unless you have a headset, people take them out of their pockets to call, answer and talk (which is when the transmitter is active.)
      .
      2) I get the feeling they are cherry picking, and glial cell cancer and acoustic neuroma were the only ones that showed a positive correlation in any studies. However, gliomas appear to be amongst the most common types of malignant brain cancers. The total brain cancer rates vary with age, but according to this Wikipedia article, they range from about 2 per 100,000 for people under 30, rising through middle age, to about 10 times that in the elderly. Only about half of those are gliomas, so it would take a study of several million people to detect a significant effect from cell phones.
      .
      For example, if the Danish study of 420,000 people had shown a 40% increase in gliomas, and half the people in the study were cell phone users, it would translate to only an additional 8 cases. If half of those people had only been using cell phones for 10 years, they wouldn’t have cancer yet, so there would only be 4 extra cases in almost 1/2 million people. So there really needs to be a huge study to prove this one way or another. (The Danish study showed no correlation with either of these cancers, or any other.) On the other hand, the small numbers means the risk is very low. On the third hand, these sound particularly nasty, you definitely don’t want to get them.
      .
      Personally, given the low overall incidence, lack of correlation in most studies, and complete lack of any plausible mechanism, I’m not too worried, but I’ll definitely breathe a sigh of relief when a definitive study shows no link.

  6. Well, I for one would like to apologize for going on the “why would anyone buy this bad science” rant. My comments posted in the last cell phone blog were out of line. Because for most of us, without a Phd in a science field and the ability to wade through the research, the WHO announcement would be enough for me to consider being very careful with my cell phone. Heck, I read there is even a study underway about the blue tooth, and wearing a cell phone on you hip or carrying it close by while using a blue tooth device. Since this is being funded by a group I would consider “scientific” it makes me look at my land line with more interest. I don’t do 30 minutes a day on my cell phone, but then again, most people I know are switching to cell phone only and not having a land line. The main worry seems to be with young people, who oddly from what I am told text.

    Point is do I believe that cell phones cause cancer anymore than other everyday things in our lives? no. Heck I know people that leave the kitchen when their microwave is running. (you can test to see if it leaks). But would I blame the average person that says “look I”m going to cut back my use, and I sure hope they hurry up with that study on the dangers of even carrying a cell phone”.

    When some important group we look to to monitor our health issues something like this, you can’t blame anyone for being concerned and making a lifestyle change. So I take back the complaining I did and apologize.

    Now, if someone concerned goes out and buys one of the seemingly hundreds of woo devices that protect you (such as Tony Blair’s wife uses) then I will complain!

    1. Yeah, I was wondering about that. I mean, lead has some nasty effects, especially on the developing brain, but I didn’t think cancer was one of them.
      Not too sure about vehicle exhaust or chloroform as carcinogens for that matter.

    2. It’s also telling that there is only 1 item in group 4 (probably not carcinogenic). It would appear that for all intents and purposes group 2B is where they put things that don’t seem to cause cancer.

  7. 3 interesting things of note. 1) The study found longer term studies tended to have more positive correlation, than shorter term studies, which supports an effect. Problem is, most of the longer term studies are retrospective, and as such aren’t as robust as a prospective study.

    2) Coffee and pickles are also on the list as possible causes of cancer. I don’t eat pickles every day, though.

    3) I can think of a plausible cause for an increase in brain cancer. Everybody thinks in terms of ionizing radiation as the “initiating event.” Cancer biology has a consensus you need an initiating event (causing the DNA damage), and a promoting event, that causes cells to proliferate (cancer and non cancer cells). Without this second signal, you may have “dormant” cancer cells with the necessary genetic mutations but they’ll never divide. If cell phones can increase inflammation, by simply causing your head to get hot, that could lead to a weak but statistical increase in the stimulating event. Of course any activity that makes your head hotter could also have an effect, such as wearing a hat, or exercising. A cell phone can heat using microwave radiation (probably minimal), but just by holding a hot phone next to your head, which can also block thermal cooling from that part of your head that would normally occur when not blocked. That said, that’s just a big guess on what could be causing it, if there is indeed an effect.

  8. The government is obviously putting pressure on the IARC and other research groups. The study may seem like there’s a weak correlation between cell phone use and brain tumors, and you could easily use the “correlation doesn’t equal causation argument,” but after all the reports I’ve read about pressure from lobbyists, scientists getting fired for identifying a causal relationship, and executives for cell phone research groups having been previous long term employees for Motorola and GSM, etc, it really seems like the conspiracy theorists might be right on this one. Besides, my neighbor was recently diagnosed with a malignant glioma and he had a satellite dish for his internet that he was using for 10 years right next to his bed on his balcony, so idk…

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