Is there evidence for a correlation between the use of mobile phones and the occurence of brain cancer? If yes, is there also evidence for causality?
This study of 420,000 danes found no correlation between mobile phone use and instances of cancer.
We found no evidence for an association between tumor risk and cellular telephone use among either short-term or long-term users. Moreover, the narrow confidence intervals provide evidence that any large association of risk of cancer and cellular telephone use can be excluded.
I just read an excellent article which discusses the WHO review. I thought it good to add the link as some have interpreted the WHO's addition of cellphones to Group 2A (Probably carcinogenic to humans) status to be "conclusive evidence".
The May report from the IARC moved cell phones from Group 4—probably not carcinogenic—to Group 2B, or possibly carcinogenic. Also in that group: coffee, pickled vegetables, engine exhaust, and working as a carpenter or a dry cleaner.
World Health Organization Reclassification
Unfortunately, the World Health Organization has just released the following:
Lyon, France, May 31, 2011 ‐‐ The WHO/International Agency for Research on Cancer (IARC) has classified radiofrequency electromagnetic fields as possibly carcinogenic to humans (Group 2B), based on an increased risk for glioma, a malignant type of brain cancer1, associated with wireless phone use.
From May 24–31 2011, a Working Group of 31 scientists from 14 countries has been meeting at IARC in Lyon, France, to assess the potential carcinogenic hazards from exposure to radiofrequency electromagnetic fields. These assessments will be published as Volume 102 of the IARC Monographs, which will be the fifth volume in this series to focus on physical agents, after Volume 55 (Solar Radiation), Volume 75 and Volume 78 on ionizing radiation (X‐rays, gamma‐rays, neutrons, radio‐nuclides), and Volume 80 on non‐ionizing radiation (extremely low‐frequency electromagnetic fields).
The IARC Monograph Working Group discussed the possibility that these exposures might induce long‐term health effects, in particular an increased risk for cancer. This has relevance for public health, particularly for users of mobile phones, as the number of users is large and growing, particularly among young adults and children.
"Given the potential consequences for public health of this classification and findings," said IARC Director Christopher Wild, "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. "
The Local (Swedish news in English) reported in 2009 on a study that has gone over 30 years of brain tumor history in Scandinavia offering the following summary (in a more readable format than the actual papers abstract).
Even though mobile telephone use soared from the 1990s , brain tumours did not become any more common, the researchers reported in the Journal of the National Cancer Institute.
Deltour's team analysed annual incidence rates of two types of brain tumour – glioma and meningioma – among adults aged 20 to 79, from Denmark, Finland, Norway, and Sweden, from 1974 to 2003. This represented virtually the entire adult population of 16 million people, the researchers said. The Scandinavian countries all have comprehensive cancer registries that record details of known cancer cases.
"In Denmark, Finland, Norway, and Sweden, the use of mobile phones increased sharply in the mid-1990s; thus, time trends in brain tumour incidence after 1998 may provide information about possible tumour risks associated with mobile phone use," the researchers wrote.
Over the 30 years, nearly 60,000 patients were diagnosed with brain tumours. While the team did see a small, steady increase in brain tumours, this started in 1974, long before mobile phones arrived.
"No change in incidence trends were observed from 1998 to 2003," the researchers noted. This would have been when tumours would start showing up, assuming it took five to 10 years for one to develop, they said.
For those interested in reading the actual study it's titled Time Trends in Brain Tumor Incidence Rates in Denmark, Finland, Norway, and Sweden, 1974–2003 published in Journal of the national cancer institute.
This issue was also brought up at the end of an interview between Richard Dawkins and Niel deGrasse Tyson from 2010 (according to YouTube) when one of the audience members asked this question (I've cut down the "uhms.." and so to make it more readable).
Question: I have a practical application question about technology and it's impact on humans, specifically cell phones cellular cell phones. I'm in health care and I'd like to know where you stand on the facts (and I know we've come a long way since the first cell phones came out), but I get particularly apprehensive when young people put cell phones to infants and go "Talk to daddy".
Niel deGrasse Tyson: With regards to cell phone use there's a very important fact to science and that is the act of measurement, it's a fascinating thing measurement, because you can never measure anything precisely. That is with unlimited precision, you can only measure it within the certainties of your measuring device and all you can do in the lab is try constrain how uncertain that measurement is, but on some level it will always be uncertain and here's what happens.
If you try to measure a phenomenon that does not exist, the variation in your measurement will occasionally give you a positive signals, as well as negative signals. If your idea is that A causes B, in this case cell phones causes cancer. Then a paper gets written about that result and then people might get concerned that cell phones cause cancer or that the power-lines might cause cancer, this go way back and so if you look at the full spade of these studies even those they don't publish because it was not a positive effect there are some cases where there is in fact less cancer and so these are the phenomenon of a no-result.
When you actually have A causing B the signal is huge and it's repeatable in time and in place in cell phones that repeatable signal is yet to emerge from the total experiments that are done with it. That being said, if you are worried on almost every cell phone they have the cell phone on the hip and you got the earpiece. Just do that if you are worried, but can either say the jury is still out or the experimental result is no effect at all.
So there seem to be a strong correlation that it does not cause cancer as well as at least one high profile physicist claiming that the experimental results are showing that there is no effect on brain cancer from cell phones.
I agree that controlled studies may take many years to reach consensus, so instead I have to question the basic science behind the idea that it could even occur in the first place.
If there were to be a causative link between cell phones and cancer rates, what is the proposed mechanism of this interaction? Cell phones only emit non-ionizing radiation. Agents of cancer causation (chemicals, energies, viruses) act by damaging DNA (by breaking the electron bonds) and producing mutations. The energy emitted by a cell phone doesn't come close to this level, and it seems to take quite a different understanding of the interaction between photons and atoms than that provided by modern quantum mechanics for any causative link to be made.
Also, which types of cancer have been included in the studies? I know the general public thinks of it only as an all-encompassing "cancer" but there are about 120 different types of brain cancers, all of which have distinct etiologies; glioblastoma, neuroma, meningioma, oligodenroglioma, astrocytoma, medullablastoma, chordoma, to name just a few.
Is there a mention of cancers thought to be caused by cell phones in structures near the brain? Acoustic neuromas, optic neuromas, parotid cancers, oral cancers, melanomas, lymphomas, esophageal cancers?
Also, wouldn't it seem reasonable to think that if cell phone radiation caused "cancer" it would cause cancer to the areas of the body which receive the most direct exposure? Shouldn't we then be looking for melanomas of the ear and face or acoustic neuromas? The ear and the skin are much closer to the phone than the brain after all.
And of course the final question, will it be easier for most people to seek the knowledge required to answer these and more relevant questions, or perpetuate the idea of some shadowy conspiracy?
The most recent studies show not that there is "no correlation", but rather that the studies are "inconclusive." Here is an article about some recent research: Brain activity during cellphone use
Quote about the brain activity study: “What it does tell us that we need to look into this,” Volkow said. “If we had seen nothing, then I think it would have been much easier to say we don’t need to worry about it.”
Studies with mice and rats have shown there may be an increase in some rare forms of cancer (in schwannoma and glial cells) but if so, the effect is very small and the mechanisms remains unclear. This does not show a link with cancer in humans (certainly, the effect cannot be large, or it would show up epidemiologically), but it does raise the physics question if there may be a non-thermal, non-ionising long term effect that we do not yet know about.
Rat studies show correlation with schwannoma
As reported by the Scientific American (Carl Schmidt, New Studies Link Cell Phone Radiation with Cancer, 29 March 2018), there have been two large scale peer reviewed studies that appear to indicate that long-term exposure to microwave electromagnetic radiation increases the incidence of a tumor called schwannoma. Both the National Toxicology Program (USA) and the Ramazzini Institute (Italy) exposed 2,500–3,000 rats and mice to microwave radiation at frequencies and intensities comparable to mobile phone usage (either near-field to model a mobile phone near the head, or far-field to model the radiation due to mobile phone towers). The article describes first the American results (emphasis mine):
The strongest finding connected RF with heart schwannomas in male rats, but the researchers also reported elevated rates of lymphoma as well as cancers affecting the prostate, skin, lung, liver and brain in the exposed animals. Rates for those cancers increased as the doses got higher but the evidence linking them with cell phone radiation specifically was weak by comparison, and the researchers could not rule out that they might have increased for reasons other than RF exposure. Paradoxically, the radiation-treated animals also lived longer than the nonexposed controls. The study results were reviewed by a panel of outside experts during a three-day meeting that ended on March 28. They concluded there was "clear evidence" linking RF radiation with heart schwannomas and "some evidence" linking it to gliomas of the brain.
And goes on to describe the Italian results, which detected elevated rates at the highest dose (emphasis mine):
As in the NTP study, Ramazzini investigators detected statistically elevated rates of heart schwannomas in male rats at the highest dose. They also had weaker findings linking RF exposure to cancer of glial cells in the brain, which were limited to females
However, those studies were entirely statistical. There is no known non-thermal effect of microwave radiation on biological tissue, and therefore also no biological explanation for the observed effect:
Samet adds a major challenge now would be to draw a biologically relevant connection between acoustic neuromas and other glial tumors in the brains of humans with Schwann tumors in rat hearts. “The mechanism is uncertain,” he says. “There’s a lot of information we still need to fill in.”
This does not contradict the results in the other answers. Epidemiological studies have been inconclusive, and many have serious limitations. The mice and rats were exposed up to 19 hours per day their entire life. Although these studies do not show a link between microwave radiation and cancer in humans, they do raise the question of the physics behind the correlation reported in the studies. Is there any non-thermal, non-ionising biological effect of long-term continued exposure to low-intensity microwave radiation? Currently, we don't know the answer to that question. Although non-thermal microwave effects exist, their nature is currently very much a field of research.