Microwave Heat
In “Can You Hear Me Now?” [Skeptic], Michael Shermer argues correctly that cell phones cannot directly break DNA. But he is wrong to assert that cancer only arises after such damage occurs or that cell phones cannot damage DNA otherwise.
A Tufts University study has found that electrical properties of one type of cell can induce other, distant cells to change their behavior. Twelve different European laboratories working as part of a European Union–sponsored project have found evidence of DNA damage from signals from modern 3G phones. Split samples of human sperm studied in six different national laboratories indicate poorer morphology, motility and increased pathology for cell phone–exposed samples. Other studies in Sweden have found that those who started using cell phones as teenagers have four to five times more brain cancer as adults.
Shermer claims that the latest WHO epidemiological studies suggest no overall increased risk in brain cancer tied with cell phone use. But this project is continuing because its leaders understand the need for continued surveillance.
Devra Davis
Department of Epidemiology
University of Pittsburgh
Shermer’s point was that there is not enough energy in microwaves produced by cell phones to cause the breakage of DNA, which can lead to cancer. Although this is true, one cannot conclude that cell phones are not carcinogenic. Research does exist—I am a co-author on a review article relating to it—discussing the carcinogenic effect of elevated tissue temperature with and without coexisting DNA damage from other causes. To my knowledge, no research exists yet on the low-temperature rises that cell phone radiation causes, the increased neurological sensitivity of young individuals, or the unlikely situation where there is known carcinogenic exposure combined with thermal exposure below thermal levels that can cause damage. Consequently, I am hesitant in this case to completely ignore the precautionary principle.
Benjamin L. Viglianti
Department of Radiology
University of Michigan at Ann Arbor
SHERMER REPLIES: [for more on this debate, see www.ScientificAmerican.com/feb2011/skeptic]: Many readers noted that cancer has many causes, such as epigenetic mechanisms that do not require the breaking of DNA chemical bonds, but these other causes are not what most critics are claiming for the alleged connection between cell phone use and brain cancer. Davis agrees with me that “cell phones cannot directly break DNA,” but then she contradicts herself by citing an E.U.-sponsored study on whether DNA damage is linked to 3G phones. The E.U. study has been discredited. The other studies she mentions are either irrelevant or have not been replicated. Viglianti makes a good point that should, in principle, be a testable hypothesis that could lead to a fuller understanding of cancer and its causes. In the meantime, I cannot help but wonder why no one seems concerned about skin cancers caused by holding cell phones in one’s hand and pressed against one’s ear.
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4 Comments
Add CommentThe following link published in both the magazine and in the letters section above does not work:
Reply | Report Abuse | Link to thiswww.ScientificAmerican.com/feb2011/skeptic
Devra Davis' comment about studies in Sweden finding "those who started using cell phones as teenagers have four to five times more brain cancer as adults" seems to rely on a common misconception about causality. After all, virtually 100% of folks who, as adults, end up strung out on heroin, started out on ... milk. Correlation is not causation.
Reply | Report Abuse | Link to thisI will be delighted to address some of the questions that Mr. Shermer presents above. He states, "...cannot help but wonder why no one seems concerned about skin cancers caused by holding cell phones in one’s hand and pressed against one’s ear".
Reply | Report Abuse | Link to thisThat is an excellent question. The only thing we need to do, is compare the doubling time of skin cells with the doubling time of neurons in the brain. We shed our skin every 35 days on average, while it is known that neurons do not regenerate - and, when they do, it is a tremendously slow process. Thus, if we ask why the cumulative effects of cancer are more visible on the type of cells that does not have the capacity to divide, and will not be so obvious on cells that are regularly and quickly shed, I think that Mr. Shermer already has the answer there.
Moreover, the peer reviewed biomedical literature already documented tinnitus and parotid gland tumors, the latest article on a 4-fold increase in parotid tumors among Israeli people was just published, and this also is helpul in dispelling Mr. Shermer's confusion about tumors or health problems that occur in regions in close proximity to the cell phone, in addition to the brain.
In addition, the EU study that Mr. Shermer refers to, has not been discredited. It is in the respective Journal, where readers can peruse it. Perhaps Mr. Shermer wants to state that the study was discredited by the industry, that might be true, but as far as the scientific community goes, that study stands as a splendid research article that was published and is still present in a first-order biomedical journal.
In addition, Mr. Shermer is factually wrong in stating that other studies have not been replicated. The ability of non ionizing radiation to break DNA was demonstrated by 6 different scientists worldwide, 6 different groups, the finding was repeated, reproduced, and validated. It is useless to refer to every article as "not having been replicated", when it is well-known that several respected investigators found and published the same effects.
You are right Jeff, correlation is not causation; but when correlations in multiple countries and in multiple organisms point towards the same association, there is a very good likelihood that it is causal. That's what biology has taught us for decades,in various systems. And just being blindly dismissive, stating that "correlation is not causation", does not bring anything positive to anyone, except perhaps the industry. We need to rely on correlations that in multiple biological systems point towards radio frequency radiation causing serious and severe health effects, as it is already obvious if you read the papers on various organisms such as C. elegans, Drosophila, mammals, rodents, and humans.
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