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Critique of “Risk of Brain Tumors from Wireless Phone Use”

Following my recent critique here of the book Disconnect by Devra Davis, about the purported dangers of cell phones to health, David Gorski asked me to comment on a recently published “review article” on the same subject. The article is entitled “Risk of Brain Tumors from Wireless Phone Use” by Dubey et al [1] published in the J. Comput Assist Tomography. At the outset, the same question occurred to both of us: what is a “review article” about cell phones and brain tumors doing in a highly technical journal dedicated to CT scans and CT imaging? While we are both still guessing about the answer to this question, we agreed that the article itself is a hodge-podge of irrational analysis.

As you might surmise, Dubey and his Indian co-authors come to the conclusion that “that the current standard of exposure to microwave during mobile phone use is not safe for long-term exposure and needs to be revised.” But within the conclusion there is also the following: “There is no credible evidence from the Environmental Health and Safety Office (I presume in India) about the cause of cancer or brain tumors with the use of cell phones. It is illogical to believe that evidence of unusual brain tumors is only because of hundred’s of millions of people using cell phones worldwide.” What?! These are opposite and contradictory statements. The main body of the article includes a lot more instances of such inconsistency.

Dubious Sources, References, & Studies

Another highly dubious feature of this review article is the nature of its sources. Many of its references are merely news reports, not scientific articles and some even come from pseudo-scientific web sites. For example, figure 1 purports to illustrate cell phone radiation penetrating a 5 year old, 10 year old, and adult head. It purports to show that cell phone radiation penetrates a child’s head much more deeply than an adult’s. The source given for this image is www.environmentalhealthtrust.org — the web site of none other than Devra Davis! The main feature on this web site is the promotion of her book Disconnect!

This particular image is one that is frequently used by alarmists. The original source is a 1996 paper by Gandhi et al [2]. This paper has long been discredited and the image is simply wrong. Gandhi himself published an update in another paper in 2002 [3] with quite different results. Numerous papers have been published examining the issue of cell phone penetration of the head. The consensus is that RF absorption in children’s heads is not greater than adults and is well within exposure limits [4].

One particularly dubious reference is to a book by the notorious industry gadfly George Carlo that even Devra Davis treats with caution. A number of the scientific papers that are listed are of dubious quality and/or have failed to be reproduced in follow up studies. For example one of the sections is entitled “Male fertility damaged by radiation.” Orac has written a critique on this hypothesis in which he takes apart one of the studies cited by Dubey et al. Male fertility is also one of the principle subjects in the book Disconnect, which I rebutted in my review on SBM. To summarize the three papers cited by Dubey et al. are of poor quality and/or have failed attempts at replication. The authors do not list or comment on the negative studies that contradict the one’s they listed.

Other statements and references that have been contradicted by follow up studies include claims that:

  • The RF emissions from cell phones have been shown to damage genetic material in blood cells
  • Long-term cell phone use can increase the likelihood of being hospitalized for migraines and vertigo by 10% to 20%
  • Cell phone radiation damages DNA, an undisputed cause of cancer
  • Cell phone radiation has been shown to cause the blood-brain barrier to leak

The fact that each one of these “findings” has failed replication attempts in rigorous follow up studies is not even mentioned.

In the conclusion, Dubey et al. makes the bold claim that: “Moreover it was repeatedly confirmed that the radiation from base stations is harmful to health. The existing ICNIRP and FCC exposure limits are based on a false premise that only thermal effects cause harm.” Here they are referring to cellular telephone base stations. But no references are provided to support either of these assertions.

Industry Funding

Figure 2 in the article is a chart that purports to show industry bias in brain tumor research. This establishes the principle theme of this article: the claim that most of the studies on brain cancer and cell phones with negative results have been funded by industry. This is not a scientific argument, it is a conspiracy theory. Other posts on SBM have observed that conspiracy theories are a favorite tactic of purveyors of pseudo-science. This “industry funding” theory is also the main thesis of the book Disconnect and alarmist cell phone web sites. The source given for this “industry funding bias” chart is the web site www.psrast.org/mobileng/mobilstarteng.htm. The organization behind this web site is a group called:  “Physicians and Scientists for Responsible Application of Science and Technology (PSRAST).” This web page is full of references to the usual unscientific alarmist material found throughout the Internet.

Dubey et al. do not mention the generally accepted alternative explanation for the dichotomy in positive vs. negative studies. First there is the issue of publication bias [5]. If a researcher makes an initial positive finding, he is more likely to rush his results to publication. An initial negative finding is less likely to ever be published. Rigorous studies with all necessary controls and a large number of trials are more expensive to conduct. It is important to note that virtually all such follow-up replication studies have been negative.

An extremely important fact that is not discussed by Dubey et al. is that expert reviews by virtually all of the industrialized world’s public health organizations have come to the same conclusion as the World Health Organization “that current evidence does not confirm the existence of any health consequences from exposure to low level electromagnetic fields.” One presumes that they have also been either co-opted or duped by this industry funded conspiracy.

Hardell vs. Interphone

By far the largest and most important case control study on the possible link between cell phones and brain cancer was the Interphone study [6]. The Interphone study was an international collaboration involving 13 countries which was coordinated by the International Agency for Research on Cancer (IRAC) which is part of the WHO. The conclusion of Interphone was “Overall, no increase in risk of glioma or meningioma was observed with use of mobile phones. There were suggestions of an increased risk of glioma at the highest exposure levels, but biases and error prevent a causal interpretation. The possible effects of long-term heavy use of mobile phones require further investigation.”

Dubey et al. characterize the important Interphone study as follows: “This nonblinded, interview-based, substantially wireless industry-funded case-control study….” They are clearly discounting Interphone with the “industry funding” conspiracy theory. They compare the Interphone studies with another set of case control studies conducted by the Swedish researcher Lennart Hardell.  “The 2 sets are the industry-funded Interphone studies and the independently funded Swedish studies reported by Hardell team.” Dubey et al. make a number of additional dubious criticisms of Interphone. To support these criticisms they list a number of letters to a journal including a couple by Hardell. Much of this criticism boils down to splitting hairs over who did a better job of controlling for “recall bias.”

Those of you who are regular readers of SBM may have seen a post by David Gorski commenting on another cell phone cancer review article in which the work of Hardell was given prominence. Gorski had this to say about Hardell: “Whenever one group of researchers keeps finding a result that no other group seems able to replicate or that otherwise disagrees with what everyone else is finding, that’s a huge red flag for me. Remove those studies, and even the wisp of a hint of a shadow of the association between cell phone use and cancer found in this study disappears. I’d have a lot more confidence in this seeming association in “high quality” studies if the association didn’t depend upon a single researcher and if this researcher was not also known for being an expert witness in lawsuits against mobile phone companies.” It would appear the Hardell himself has a conflict of interest.

A pair of review articles on cell phone brain cancer studies in the journal Epidemiology [7, 8] had this to say about Hardell: “One notable feature of the literature to date is that authorship by Lennart Hardell is associated with finding an adverse effect of mobile telephone use for several different endpoints. The discrepancy between the findings of Hardell and those of other scientists was striking enough that Ahlbom et al presented some of their summary findings in 2 forms, including and excluding the studies by Hardell and colleagues.”

Case control studies such as those conducted by Hardell and Interphone involve recruiting subjects who have been diagnosed with brain cancer. The subjects respond to a questionnaire in which they are asked to recall – purely from memory – how much they had used their cell phones over the years. The cancer patients are matched with a healthy control group who respond to the same questionnaire. If the study shows that people who have brain cancer used cell phones more that the controls, the conclusion is that cell phone use increases the risk of brain cancer.

But case control studies such as this suffer from a number of limitations, the most serious being “recall bias.” Brain cancer patients are certainly aware of the theory that cell phone use may lead to brain cancer. This theory has been in the news for years. Such patients are likely to over report past cell phone use when completing a questionnaire. Memory is notoriously unreliable, and it becomes more so over time. I don’t know about you, but I could only make a wild guess about how much I used my cell phone 10 years ago. This simple fact alone makes it hard to interpret conflicting studies.

Dubey et al. seem to acknowledge the issue of recall bias, but their treatment of the issue is inconsistent and contradictory. The authors even discount one of Hardell’s studies with the following: “this finding is probably explained by recall bias, with patients with glioma systematically overreporting use on the same side as their tumor and consequently underreporting use on the opposite side.” Yet despite this admission, Dubey et al. accept all of the Hardell studies and include them in their meta-analysis. They give greater credence to Hardell than Interphone and conclude: “The meta-analysis shows that long-term cell phone use can approximately double the risk of developing a glioma or an AN (acoustic neuroma) in the more exposed brain hemisphere.” This opposite to the conclusion of mainstream scientists as reflected in papers such as Ahlbom et al. [8].

What about incidence rates?

Perhaps the simplest and most compelling argument against any possible cell phone brain cancer association is the fact that brain cancer incidence rates have remained unchanged since the introduction of cell phones. Dubey et al. dismiss this evidence with a one sentence section entitled: “Outdated Central Brain Tumor Registry of the United States Tumor Data” and the statement that “the most recent data are already at least 4 years outdated.” The authors reference only a couple of older studies, and ignore the most recent ones from Europe, the US, and the UK that show no increase in brain cancer incidence up to 2003, 2006, and 2007 respectively [9, 10 11]. Furthermore, the data in the US & UK studies are more recent than any of Hardell’s studies!

Conclusion

The Dubey et al. review article is sprinkled with statements such as:

  • Most studies have not found any association between cell phone use and the development of head tumors
  • There is generally a lack of convincing and consistent evidence of any effect of exposure to RF field on risk of cancer
  • Although some positive findings have been reported, so far the totality of epidemiological evidence (meningioma) does not demonstrate an increase in risk of meningiomas related to mobile phone use
  • There was no association between the use of cellular or cordless phones and salivary gland tumors found, although few studies reported for long-term heavy use

As I wrote at the beginning of this review: these statements are opposite and contradictory to the overall conclusion of Dubrey et al. One supposes that the authors are trying to give the appearance of “balance.” However they reconcile these contradictory findings not with a scientific weight of evidence approach, but with their “industry funding” conspiracy theory. This brings me to add an additional question on top of our original query about what an article about cell phones is doing in a specialized journal on CT imaging. How did an article that promotes Internet conspiracy theories with a hodge-podge of irrational analysis even get published at all?

About the Author

Lorne Trottier is a co-founder of Matrox Ltd. and holds B. Eng., M. Eng., and Doctorate (honoris causa) degrees from McGill University. He has had a lifelong passion for science and technology and believes in the importance of combating pseudoscience. He is President of the Board of the Montreal Science Center Foundation, and is also a board member of a number of science outreach organizations including the NCSE, CFI Canada, and The Planetary Society. Trottier sponsors the annual Trottier Symposium at McGill University that deals with a variety of science topics of interest to the public, such as Confronting Pseudoscience. Trottier also maintains a web site on the subject of EMF and Health.

References

  1. Risk of Brain Tumors from Wireless Phone Use J Comput Assist Tomogr Vol 4 No 6,Nov/Dec 10. doi: 10.1097/RCT.0b013e3181ed9b54
  2. Gandhi O P, Lazzi G and Furse CM. Electromagnetic absorption in the human head and neck for mobile telephones at 835 and 1900 MHz IEEE Trans. Microw. Theory Tech. 44:1884–97, 1996. doi: 10.1109/22.539947
  3. Gandhi O and Kang G. Some present problems and a proposed experimental phantom for SAR compliance testing for cellular telephones at 835 and 1900 MHz Phys. Med. Biol. 47:1501–18, 2002. doi: 10.1088/0031-9155/47/9/306
  4. Beard et al. Comparisons of Computed Mobile Phone Induced SAR in the SAM Phantom to That in Anatomically Correct Models of the Human Head, IEEE Trans. Electro Comp, Vol. 48, No. 2, May 2006. doi: 10.1109/TEMC.2006.873870
  5. Vijayalaxmi et al. Genetic Damage in Mammalian Somatic Cells Exposed to Radiofrequency Radiation: A Meta-analysis of Data from 63 Publications Radiation Research 169, 561–574, 2008 doi: 10.1667/RR0987.1
  6. Cardis et al. Brain tumour risk in relation to mobile telephone use: results of the INTERPHONE international case-control study Int’l Journal of Epidemiology 2010; 1–20. doi: 10.1093/ije/dyq079
  7. Rothman. Health Effects of Mobile Phones Epidemiology Vol 20 No 5, Sept 2009. doi: 10.1097/EDE.0b013e3181aff1f7
  8. Ahlbom et al. Epidemiologic Evidence on Mobile Phones and Tumor Risk Epidemiology Vol 20 No 5, Sept 2009. doi: 10.1097/EDE.0b013e3181b0927d
  9. Inskip et al. Brain cancer incidence trends in relation to cellular telephone use in the United States, Neuro Oncol 12(11): 1147-1151 , 2010. doi: 10.1093/neuonc/noq077
  10. Deltour et al. Time Trends in Brain Tumor Incidence Rates in Denmark, Finland, Norway, and Sweden, 1974–2003, J Natl Cancer Inst,101(24):1721–4, . 2009 Dec 16. doi: 10.1093/jnci/djp415
  11. Vocht et al. Time Trends (1998–2007) in Brain Cancer Incidence Rates in Relation to Mobile Phone Use in England Article first published in Bioelectromagnetics online 28 Jan 2011. doi: 10.1002/bem.20648

Posted in: Clinical Trials, Epidemiology, Science and Medicine

Leave a Comment (14) ↓

14 thoughts on “Critique of “Risk of Brain Tumors from Wireless Phone Use”

  1. xwolp says:

    I’m aware that most “positive” studies are simply post-hoc rationalizations and unreliable surveys that amount to push-polling but you would thing there would be a significant positive correlations between different professions, some of which are far more extensive users than the general populous.

    Probably just another part of the conspiracy, good study design seems to always be unfavorable to these types of claims after all.

  2. windriven says:

    “From 1990 to 2002, the overall age-adjusted incidence rates for brain cancer decreased slightly; from 7.0 cases to 6.4 cases for every 100,000 persons in the United States.” – National Cancer Institute (http://seer.cancer.gov/statfacts/html/brain.html)

    I have had a difficult time finding solid historical numbers for cell phone subscriptions by year but it is safe to say that cell phone usage has increased dramatically during that same span. Even allowing for a lag between exposure and diagnosis, a decline is counter-intuitive.

  3. David Gorski says:

    Figure 2 in the article is a chart that purports to show industry bias in brain tumor research. This establishes the principle theme of this article: the claim that most of the studies on brain cancer and cell phones with negative results have been funded by industry. This is not a scientific argument, it is a conspiracy theory.

    In all fairness, it is actually relevant to mention funding sources. There is copious evidence, for example, regarding pharma-funded studies that they are more likely to have positive results. What one has to remember is that it is not sufficient to mention funding sources as a potential source of bias. Simply because a study is industry-funded is not enough reason to dismiss it. You also have to be able to demonstrate why it is fatally flawed. This is where the vast majority of criticisms of industry-funded studies fail. They only go as far as “industry funded it” and dismiss it as hopelessly tainted, failing to actually explain why it should be dismissed.

    A better approach is to explain why a study is of poor quality and its conclusions should be doubted and then, only at the end, mention its funding source.

  4. IanFrazer says:

    Having read the article, I was struck by the poor writing skills employed. It appears that sentences were simply “dropped in”, out of sequence as it were.

    The incredible over use of FUD words & phrases such as “cause of cancer”, “risk of cancer”, “promote cancer” (30 times), “tumor” (56 times) in 9 pages was striking. The over-all tone of the body of the article seemed to be frantically trying to make the point that regardless of everyone else’s results from the entire world medical &/or scientific communities, there really, truly, absolutely is a cancer causal relationship (sound of feet stamping in background)!

    The completely opposed statements such as “Investigations suggest that the use of a mobile phone for 10 or more years can dramatically increase the risk of developing a tumor” Vs. “Most studies have not found any association between cell phone use and the development of head tumors” is perplexing and downright puzzling.

    Over-all, a poorly written smear job against use of cellphones and WiFi by the “anti-crowd”.

  5. DBonez5150 says:

    I find it hilarious how the conspiracy crowds only blame causes they are aware of. As an electronics engineer, I’m aware of so many sources of electromagnetic radiation (not the ionizing type of radiation!) that are never even mentioned. Everything from computer monitors, ipods, power lines, electronics in car interiors, blow dryers, etc. bombard us with electromagnetic fields of varying strengths and frequencies constantly. Why cell phones? I guess they are an easy target, very common, maybe given to children against the wishes of “responsible, concerned (i.e. good) parents” and they have deep pockets. I’m pretty sure if there was a direct, causal link, we’d see the results pretty clearly.

    It reminds me of a silly article I read about a British women who is “allergic” to modern living ( http://www.dailymail.co.uk/news/article-443717/Im-allergic-modern-living.html ). It describes the rigorous (ridiculous?) efforts she goes through to avoid EMF. Yet, in the article’s picture, she casually stands next to a toaster. I suspect she doesn’t know (ahem, placebo) toasters throw off huge magnetic fields when in use despite her claims of her house being an “radio-wave free zone.”

    Puuuullleeease

  6. windriven says:

    “Over-all, a poorly written smear job against use of cellphones and WiFi by the “anti-crowd”.”

    One has to wonder why it was submitted to JCAT and why it was accepted by them for publication. Who were the peers reviewing this?

  7. morrisonbooks says:

    Since you are all pretty smug about what you don’t know and certain of what you do then will someone tell me and the others why the head of the interphone study just issued a warning that people should be cautious with cell phones and they should be kept away from children? it depends on who is interpreting the study. there is a clear correlation between cell phone use and increased brain cancer incidences. brain cancer is going up and many of you know people who have brain cancer who are heavy users. there is a 10-30 year time frame for cancer to develop. cancer has overtaken other causes of death for children in the u.s.
    are any of you also aware that motorola is now adding brain cancer warnings and other very specific health warnings to their manuals???????????????????????????!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    One study comes along and you all glom onto it and jump for joy.

  8. windriven says:

    @morrisonbooks

    Who the hell are you to come on this site and call any of the bloggers or commenters smug? This suggests, right out of the gate, that you are more interested in rabble-rousing than in exploring the issues surrounding cellphone use and human health.

    Then you say – absent any citation whatsoever – that, “there is a clear correlation between cell phone use and increased brain cancer incidences.” In a comment preceding yours I pointed out (with citation) that incidence of brain cancer is actually falling slightly. Let’s see: National Cancer Institute versus unsubstantiated claim of anonymous writer.

    Then you go on to say that, “motorola (sic) is now adding brain cancer warnings and other very specific health warnings to their manuals?” I have no idea whether or not your assertion is true. But it is almost immaterial. Motorola and other companies insert all manner of warnings and cautions in manuals and warranties for defensive legal purposes. That, in and of itself, has nothing to do with the scientific merit of the statement.

    This blog is about medicine based on solid science, not irrational fears, wishful thinking or magic. If you have a meaningful citation to support your allegation that brain cancer rates are increasing and that cell phone usage is correlated to those rising rates, lay it out here. You will find a receptive audience. No one here is a shill for the cell phone industry.

    But if, on the other hand, you’re just a wound-up windbag, take your febrile imagination down the road because no one here is likely to be interested.

  9. Charon says:

    And on the science-based medicine side, as opposed to evidence-based medicine, I note that cell phones don’t emit ionizing radiation. Case closed. (There is some heat deposition, but it’s negligible.)

    (I also note that physicists call anything moving at relativistic speeds, including all light, “radiation”. It’s not surprising that the average person hears “radiation” and thinks of atomic bombs, but it is sad. Radiation is also what lets you see. And makes all our crops grow.)

  10. Narad says:

    Sweet Jesus, I just came across an earlier Mercola take on the subject. I had no idea that waterbed heaters could cook my brain even when switched off.

  11. trrll says:

    I think that one reason why this has been such a contentious issue is that it is necessary to know something about biology and chemistry, and also something about the physics of electromagnetic radiation, in order to understand why it would be really remarkable if RF radiation caused lasting biological changes aside from heating (which is only significant at radiation intensity far in excess of that produced by cell phones).

    Basically, a photon of cell-frequency RF radiation carries less energy than the kinetic energy of an average water molecule, an enormous number of which are constantly slamming into all biological molecules. So if randomly absorbing that amount of energy could cause some kind of long-lasting harmful change, it would be happening all the time just from Brownian collisions with water. In particular, the energy of an RF photon is far less than what is needed to create any kind of lasting chemical change, such as. Thus, a photon of cell phone radiation can be said to deliver what might be regarded as a homeopathic dose of energy.

    What this means is that for RF radiation to do something to a cell, there would have to be some sort of highly efficient molecular mechanism for utilizing that tiny speck of energy to trigger some use of biological energy to change something in a cell. An example of a biological system designed to utilize energy from photons to do things in a cell is the photoreceptors in our eyes. Optimized by millenia of evolution, they are sensitive enough to produce a signal from absorption of a single photon of visible light. The ability of the rhodopsin of our photoreceptors to detect light is based upon a very sensitive molecular change–not a covalent modification, but merely a twisting of a single molecule, but rhodopsin is coupled to a biological amplifier in a sophisticated way such that this subtle change can alter membrane electrical currents driven by the cell’s energy stores. Yet even this incredibly sensitive system lacks the sensitivity to detect photons in the cell phone frequency range, because the molecular isomerization that gives the visual system its great sensitivity nevertheless requires orders of magnitude more energy that a cell phone photon is capable of delivering.

    So it would be truly astonishing if any species were to be found with the ability to so much as sense cell phone radiation–and far more amazing if such radiation were to cause even the slightest amount of harm to a cell. This certainly falls into the category of an extraordinary claim–and we are thus well justified in demanding extraordinary evidence, much stronger that the rather low bar of statistical significance established to test hypotheses that (in a Bayesian sense) have a much greater level of prior probability.

  12. Narad says:

    I think I can spec this out: (1) Too many photons, too soon. (2) The example of the eye demonstrates that absorption of microwave radiation through the skull is an evasion of the body’s natural filtering mechanisms. (3) To wit, vitamin D.

  13. stanmrak says:

    Who needs conclusive evidence? Personally, I’m not going to wait until science knows for sure… remember how doctors used to recommend cigarettes?

    Use the cellphone sparingly, use the speakerphone and keep some distance between your brain and the phone – it costs nothing.

    This holds true for any type of electrical device as well… taking precautions is easy. You don’t need that laptop actually on your lap, and you don’t need electrical devices next to your head as you sleep.

  14. Chris says:

    stanmrak:

    Personally, I’m not going to wait until science knows for sure… remember how doctors used to recommend cigarettes?

    Actually, no. I do remember tobacco companies hiring actors to pretend to be doctors for advertisements, they were reacting to the real science from the first half of the twentieth century showing smoking caused cancer. Research that was pretty conclusive by the 1950s: Cigarettes and the US Public Health Service in the 1950s:

    In 1950, 3 classic papers were published linking cigarette smoking and lung cancer.9–11 All 3 studies used the retrospective case–control method, comparing the smoking habits of lung cancer patients with those of a control group without lung cancer, and were cautious about asserting a causal link. There had been work before World War II on the relationship between smoking and health,12 but it was only during the 1950s that the issue came to the forefront of the American scientific community.

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