Not really.
Every time I try to assuage the misgivings of a friend or acquaintance who is worried about the supposed cell phone use/brain cancer link, I mention the selfsame facts that professor Robert Park is, I suppose, tired to repeat in his excellent What’s New newsletter: there’s no known mechanism that might allow radiation in the cell phone energy range to cause the kind of biological damage necessary to induce cancer.
The point is quite straightforward: electromagnetic energy comes in distinct packets, the photons; each frequency range – radio, microwave, infrared, visible light, ultraviolet, X-rays, gamma rays – is composed of photons of a specific energy level. Cell phone radiation is at the radio and microwave level; cancer-causing radiations come from the ultraviolet and above.
To say that mobile phone photons can hurt a brain cell enough to kill it or to turn it cancerous is tantamount to say that you may perforate a man’s heart by throwing .38 bullets at his chest – although not with a gun; with your bare hands.
But almost every time I give someone this “no known mechanism” bit of wisdom, I get a gamut of replies in a spirit that may be distilled as “Yeah, people said that about tobacco too, and now…”
Well, there’s some truth in this and I won’t deny it. For decades, the tobacco industry defended its products using, amongst other arguments, something like the “no known mechanism” line. So, with a clear precedent of big business muddling the scientific waters for profit and in blatant disregard of human health and wellbeing, shouldn’t we take the cell phone defenders with a grain of salt?
For instance: when, last February, the Journal of the American Medical Association published a report informing that there’s an increase in blood flow to the part of the brain closer to the cell phone antenna when the gadget is turned on, shouldn’t we read something more between the lines? When the authors of the report conclude that the effect of the antenna radiation in the user’s brain, if any, is not clear, shouldn’t we take the hint assume the worst, as the smokers of the 20th century should have, in similar circumstances?
No, we shouldn’t. The crux, here, is the statistical evidence. People who make the tobacco/cell phone parallel are right in that the “no know mechanism” argument may not be enough: human beings have known about poisons millennia before the necessary chemical and biological knowledge was amassed to give us a “known mechanism” for poisoning.
But the shrewd use of simple observation and induction – preferentially, in its more sophisticated guise, statistical analysis – is able to prove (or at least to strongly suggest) a cause and effect relationship, even when the precise movement from start to end remains unknown. In the case of tobacco and cancer, a statistical relationship was established by German researchers as far back as 1930. In the 1940s, the American Cancer Society began to warn about the health pitfalls of smoking, but admitted that there were "no definite evidence" linking smoking and lung cancer.
And what about the statistics of cell phone use and brain cancer? Well, just a week before the publishing of the Jama cell phone/blood flow paper, the University of Manchester, in the United Kingdom, issued a press-release with the title "Mobile phone use not related to increased brain cancer risk". The release describes a statistical analysis of the number of new brain cancer cases detected in the UK from 1998 to 2007. The idea was that, if cell phone radiation really caused brain cancer, the people who had adopted the gadgets between 1990 and 2002 – when the use of the technology had a burgeoning growth in England – would start to flood the health care system some five to ten years later. The results? Nothing.
The expected correlation just wasn’t there. So, recapitulating: in the case of tobacco, for decades the smokers did have lots of statistical evidence, but no known mechanism linking their filthy habit to lung cancer; in the cell phone case, there’s no known mechanism and no statistical evidence, either.
Hence, the parallel is false.
Carlos Orsi is a Brazillian science journalist and blogger. One of his papers has been published in the 2010 Winter Edition of the Baker Street Journal . He also writes a regular blog at http://carlosorsi.blogspot.com). When he is not writing about science, MR. Orsi is also an escience fiction writer with two novels published in Brazil: Nômade (Nomad) and Guerra Justa (Just War).
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