Does Cell Phone Use Cause Cancer? No.

Josh Harkinson at Mother Jones recently posted an item called "Scores of Scientists Raise Alarm About the Long-Term Health Effects of Cellphones." I like Josh's work, but there are some problems with this article I want to point out, some of which parallel problems in the more general discussion of cell phone safety.

Before looking at the Mother Jones piece, here's the bottom line: There is no known mechanism by which cell phone use can lead to cancer (usually, brain cancer is of concern). There have been many studies on this and related issues. They vary in quality and in what they look at. The studies that seem to indicate an increase in some kind of cancer with cell phone use would indicate a shift from a very very very unlikely chance of cancer to a very very unlikely chance of cancer. So if there is an effect reflected in this research, it is very small. The studies that seem to show a link are generally done by a limited group of researchers, use methodology that is not reliable and can not be used to attribute cause, and are situated within a literature that includes many studies that show no link. Different studies that may show a link between cell phone use and cancer often indicate a link to a different cancer. And, tellingly, brain cancer rates over recent decades are basically flat, cell phone use explosive. If cell phones increase the risk of brain cancer, it is a phenomenon that a lot of research has failed to clearly demonstrate, and if the effect is there, it is very small and entirely unexplained by physics or physiology.

Josh Harkinson discusses an important topic but does so that in a way is uncomfortably click-baity. (I assume this is in part the effect of the editors who chose the title and possibly the accompanying graphic). The title implies that science raises a concern (an alarm) and the article is accompanied by a doctored photograph of a woman using a cell phone; She is wincing as though suffering a health effect and red cell phone cancer-kooties are seeping into her head right there in the picture. The subtitle invokes the children: "Children in particular may be vulnerable." And, the article begins with an appeal to the latant distrust, "Are government officials doing enough to protect us."

The article stems from a letter signed by "195 scientists from 39 countries" who "have collectively published more than 2,000 peer-reviewed papers on the subject." How many scientist deal with the topic of non-ionizing radiation (the kind of kootie stuff that emanates from your cell phone) interacting with tissue (what your head is made out of)? I'm not sure, but a Google Scholar search on the term "biological health effects non-ionizing radiation" yields over 14,000 results. There are probably tens of thousands of scientists who work in the general area of radiation-cell interaction. This is a huge and important area of research. Various kinds of radiation have health consequences. Radiation interacting with tissues is a widespread form of therapy and imaging (everything from x-rays to MRI). The properties of various kinds of radiation and the activity of molecules in cells is part of a lot of basic research in a lot of fields. Here in Minnesota, there are probably way over 200 scientists who routinely engage in research either about or relying on the basic physics and physiology of radiation-cell interaction. It is a big area, only some of which directly addresses health effects of non-ionizing radiation, but even that small percentage involves a lot of work, many research labs, a large number of scientists, and a lot of publications.

The letter and information about it can be found here. Watch the video. Note that the "scientists" are actually "scientist and engineers," an unintended dog-whistle indicating the padding of consensus claim. The letter is not about people holding cell phones to their heads. It is about EMF in general (with a focus on cell phones), and suggests that the ambient EMF including power lines are the problem. This borders on Chemtrail like ideation. I strongly recommend you watch the video. Critically.

A letter with under 200 signers (across 39 countries) who claim to have published a couple of thousand papers on a topic is numerically weak. The reality and importance of anthropogenic global warming is a scientific consensus. Even so, climate science denialists have come up with lists and letters like this with much more impressive numbers, but thay amount to nothing. There are a lot of scientists out there. There are about seven million scientists. It is not hard to find a couple hundred who strongly believe something that many many more don't accept as likely. Josh's article does not address this context, and probably should.

That cell phones may cause cancer has been officially designated by the World Health Organization as "possible." That sounds bad. But people need to understand, and Josh did not point this out, that the "possible" category includes anything where there is virtually any research indicating a possible link, even crappy research, and even if the research exists among a huge body of research that fails to indicate a link. There are many different categorizations of cancer risk, and different organizations maintain these definitions and lists. The International Agency for Research on Cancer, part of WHO, has these categories:

Group 1: Carcinogenic to humans
Group 2A: Probably carcinogenic to humans
Group 2B: Possibly carcinogenic to humans
Group 3: Unclassifiable as to carcinogenicity in humans
Group 4: Probably not carcinogenic to humans

Items in group one are really problems. They cause cancer and include such things as silica dust, Radon, Soot, Tobacco, and Thorium. Group 2A (Probable) is pretty long and includes a lot of nasty stuff with multi-syllabic names, as well as ultraviolet radiation. Being a hairdresser is a probable cause of cancer because of exposure to chemicals, as is working in a petroleum refinery, or being a shift worker involving changing time of work on a regular basis. These are things that we may want to worry about, but that people still argue about, but, as they say, probably are linked to cancer.

Group 2B, "possible," the list cell phones are in, is very long, over 900 items, of which about a third are specifically considered possibly linked to human cancers (the others not linked to humans). This list also includes a lot of scary looking stuff, but for which there is insufficient research to actually make the link. Vinyl acetate is an example. It is a liquid precursor for a polymer used to make a lot of stuff. Wikipedia tells us, "On January 31, 2009, the Government of Canada's final assessment concluded that exposure to vinyl acetate is not considered to be harmful to human health. This decision under the Canadian Environmental Protection Act (CEPA) was based on new information received during the public comment period, as well as more recent information from the risk assessment conducted by the European Union." So that is an example of a scary sounding thing for which some research may have shown a cancer link but that was ultimately determined by at least one major agency to not be cancer causing. Potassium bromate. Used for a lot of things, it is in some of your food (baked goods mainly). It is banned in many countries, not in the US. In theory, it is broken down during baking. Coffee. Coffee has been some research indicating a link between coffee consumption and bladder cancer, but other studies show a reduced risk of intestinal cancer. Overall, the evidence for any of this is weak.

Group 2B listing is used when there is limited evidence of a cancer link and usually insufficient evidence for a cancer link in lab animals. Let's put a finer point on it by looking at what the UN says about the 2A and 2B categories (emphasis added):

Group 2A: The agent is probably carcinogenic to humans.

This category is used when there is limited evidence of carcinogenicity in humans and sufficient evidence of carcinogenicity in experimental animals. In some cases, an agent may be classified in this category when there is inadequate evidence of carcinogenicity in humans and sufficient evidence of carcinogenicity in experimental animals and strong evidence that the carcinogenesis is mediated by a mechanism that also operates in humans. Exceptionally, an agent may be classified in this category solely on the basis of limited evidence of carcinogenicity in humans. An agent may be assigned to this category if it clearly belongs, based on mechanistic considerations, to a class of agents for which one or more members have been classified in Group 1 or Group 2A.

So, if you want to be careful, avoid Group 2A items. They may cause cancer, and you should worry about them.

Group 2B: The agent is possibly carcinogenic to humans.

This category is used for agents for which there is limited evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals. It may also be used when there is inadequate evidence of carcinogenicity in humans but there is sufficient evidence of carcinogenicity in experimental animals. In some instances, an agent for which there is inadequate evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals together with supporting evidence from mechanistic and other relevant data may be placed in this group. An agent may be classified in this category solely on the basis of strong evidence from mechanistic and other relevant data.

If you focus on the word "cancer" Group 2B may be scary to you, but many items on this long list are those for which we simply can not say there is no research project ever done that showed a possible link.

Josh notes that "For decades, some scientists have questioned the safety of EMF, but their concerns take on a heightened significance in the age of ubiquitous wifi routers, the Internet of Things, and the advent of wearable technologies like the Apple Watch and Fitbit devices, which remain in close contact with the body for extended periods."

This points to a possibly unintended side effect of unnecessary concern over non-ionizing radiation. Non ionizing radiation is radiation that does not alter matter at the sub cellular level in a way that can lead to cancer or other negative effects. See this writeup for more detail on this important difference. All radiation reduces in its strength dramatically with distance. As your smart phone and your wi-fi router exchange information (when it is using that pathway to interact with the internet) the energy that comes out of the box across the room and the energy that comes out of the smart phone in your hand, at the point of, say, your nose (a proxy for your brain that allows us to discount the effects of your skin, skull, and dura matter reducing the signal) are many orders of magnitude different. Conflating concern over a cell phone pressed to your head with concern for wi-fi routers is like conflating concern over drowning in a pool with concern over drowning in the vapor that evaporated from the pool that give you that dank feeling as you sit nearby drinking your iced coffee drink form a polyvinyl acetate cup.

Except there really is a demonstrable risk of drowning in a pool.

This is a problem because there is a movement to remove wi-fi from all public spaces over health concerns. That is crazy talk. I wish Josh had noted that in his piece. The people who signed this letter are those same people ... who want to remove wi-fi from your coffee shop.

A very very small number of researchers want to move cell phones from Group 2B to Group 2A, but even as they are asking for this, continued research on the cancer risk of cell phones a) fails to produce a mechanism by which this can happen despite a great deal of knowledge about radiation-tissue interaction and b) continues to show a possible link only in studies that are inherently flawed in their methodology. Such studies, mainly case-control studies, rely on people recalling their use of cell phones. People with brain cancer are asked to recall their cell phone use, and matched randomly chosen people without brain cancer are asked to do the same thing. (Not all studies are done just that way but key studies of relevance here were.) That is a great way to get a preliminary look at a possible health issue, but it is simply not how the actual connection between a substance, a technology or a behavior and a health effect is made.

We understand a lot about energy-tissue interaction. If non-ionizing radiation from cell phones caused cancer, we would have an inkling of the mechanism. We don't. Cell phone use has exploded in recent decades, brain cancer has not. If cell phones caused brain cancer, it would be a visible epidemiological phenomenon. It is not.

I've been told (and some checking on the internet has indicated this is maybe important) that some of the material used to make cell phones comes naturally along with some radioactive isotopes. It is possible that these isotopes are not always removed properly. I do not know this is the case, but it is an interesting idea. A while back a shipment of cell phone cases that happened to be radioactive was located (and refused). Holding a radioactive cell phone case to your head several hours a day may be a health risk, though again, I don't know this to be a fact, it probably depends on all sorts of things. The cell phone-cancer link is so weak that it may be a result of research bias, random effects, recall bias, or some effect related to the use of the cell phone but not to the non-ionizing radiation.

Smart phones are becoming so ubiquitous that they could almost be considered a key trait of our species. It is smart to be smart about smart phones. Worrying about the cancer link is probably not exactly stupid, but it isn't particularly smart either.

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This video addresses many of the topics I touch on here, and more: