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Re: [Phys-l] Mobile 'phone and cancer, not again?



At 7:51 PM -0700 4/1/08, Bernard Cleyet wrote:

Mobile phones could kill far more people than smoking or asbestos, a study by an award-winning cancer expert has concluded. He says people should avoid using them wherever possible and that governments and the mobile phone industry must take "immediate steps" to reduce exposure to their radiation. The study, by Dr Vini Khurana, is the most devastating indictment yet published of the health risks.

It draws on growing evidence - exclusively reported in the IoS in October - that using handsets for 10 years or more can double the risk of brain cancer. Cancers take at least a decade to develop, invalidating official safety assurances based on earlier studies which included few, if any, people who had used the phones for that long.

I would have two questions before giving this study a whole lot of credence. First, is does. Khurana have epidemiological experience? The article lists him as a neurosurgeon, but the study is clearly epidemiological in nature, and epidemiology involves some statistical techniques that non-members of that profession are not always familiar with and could lead to flawed results in inexperienced hands.

Second, does he propose a mechanism by which radiation of that low intensity and photon energy can induce the cancers he warns about?

I sounds to me like he has found a correlation and assumed it to be a causal relation. It may be, of course, but, again it may not be.

The article also paints the results in the most alarmist tones. But what is the actual incidence of malignant brain tumors in various populations? He may include that data in his peer-reviewed article, but this was merely a news report, and the impression it leaves is that everyone who uses a cell phone for ten years is going to get brain cancer. I find this sort of reporting very misleading. I'm all in favor of giving the public all the information, so they can make a decision based on the facts, but if the incidence of malignant brain tumors in in non users is only, say, 1 in 100,000 (I have no idea what the actual number is, so this is just for purposes of example), and Dr. Khurana has found, say, that the incidence among heavy cell phone users is double the base rate after 10 years, that is still only 2 per 100,000. Hardly something to raise major alarms about, but definitely something that people should be told about, so they can make their own decisions about using cell phones.

It also seems to me that it is important to propose a mechanism by which the effect observed could occur. If the mechanism is known, then it become possible to take action to mitigate the effects causing the problem. I admit that we often don't know the specific causes of many diseases, or even how some medications work, but it remains important to seek those mechanisms, not only to improve our understanding, but also to clearly establish any causal links that may exist. Without those causal links, the correlation argument remains weak, especially in those case where the signal to noise ratio is low.

Also, this seems to be a crusade by one person, who has become obsessed with his observation. Are there any others corroborating this research, or countering it (other than those employed in the cell phone industry)? I have seen reports of study after study that have reported one dire prospect after another, only to have the reports sink back into the woodwork of non-verifiability.

As I write this, I am thinking about Alice Stewart, and her almost lone crusade against the indisdcrimate use of x-rays, because of their cancer-causing potential. She was eventually proved right, but only after suffering years of vilification for her efforts, not only from the radiologists, who saw her work as threatening their rice bowl, but from her more conventional colleagues who didn't see any need to do the type of detailed analyses that she became famous for. And even though, she didn't know the causal link when she first found her results, it was eventually established, and has left her work well-grounded, rather than depending on only statistical analysis.

So I hesitate to condemn this work that that of a crank. He may be right, but it is important that the work be carefully checked for errors and improper analyses, and also that an effort be made to establish a causal mechanism before one get on the ban-the-cell-phone bandwagon.

Hugh
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Hugh Haskell
<mailto:haskell@ncssm.edu>
<mailto:hhaskell@mindspring.com>

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Hard work often pays off after time. But Laziness always pays off now.

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