Posted by: cg00n | July 8, 2009

A Minor Reality Check

My paragraph about Brynnesa Gradley seems to have provoked more commentary than usual so I thought I should post this message I received from Dr. E.E of Toronto:

Though the young lady with the melanoma had the real thing, a) it may not have had anything to do with the sunbeds (there is increasing evidence, now that someone is actually looking for it and not just assuming that melanomas have the same risk factors as solar keratoses) that at least a significant proportion of them are not in fact related to sun exposure (witness your heel); b) there has been a category creep in the definition of “dysplastic naevus” and “melanoma” over the past 10 years that has resulted in many things being called that now which would previously have been regarded as a regressing naevus  This has two effects – one is that the numbers of cases appear to rise alarmingly, the other is that the surgeons get really good cure rates! Secondly, Vitamin D from pills is not the same as getting it from sunshine – I’m sure that chemically, one molecule is the same as the other, but there is a whole range of goodies [that come from sunshine], most of which we know nothing about. Thirdly, if you have never really been addicted to something, you might want to revise your statement about people still smoking – there are some things worse than death, and trying to kick an addiction is sometimes one of them.

I have the highest regard for Dr. E.E whom I have known for a long time.  She often questions conventional wisdom and usually has good reasons for doing so.  This would certainly not be the first time that dubious statistics, over-simplification and the band-wagon effect have produced a consensus among scientists that has subsequently turned out to be wrong.  Having quite unintentionally stirred up this whole controversy I am perfectly willing to admit that I may be totally out to lunch.  However, I don’t really want this issue to take over this blog so this is my last posting on the subject.

One thing I can say with certainty is that I have never had to kick a serious addiction but I doubt if I would be any better at doing so than I am at keeping my head together during my current situation.  It never occurred to me that it might be a “worse than death” experience.  From now on I will look at it in a whole new way.

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Responses

  1. The WHO has a press release, linking to factsheets, on tanning:
    http://www.who.int/mediacentre/factsheets/fs287/en/

    There is a heavier, more extensive literature review:
    ICNIRP (2003) International Commission on Non-Ionizing Radiation Protection. Health Issues of Ultraviolet Tanning Appliances Used for Cosmetic Purposes. Health Physics 84: 119-127.
    Free online at http://www.icnirp.de/documents/sunbed.pdf

    This says ‘A “safe” level of solarium use does not exist.’ and advises against all non-prescription use.

    From the summary of other studies, it seems that the *correlation* between tanning-parlour visits and skin cancer is very well established, but the *causality* is harder to determine. One can’t ethically study something that is almost sure to be harmful by exposing randomly-selected people to it.

    Without a randomized, controlled study, it’s difficult to separate out other effects that might cause the correlation. Tanning parlour radiation is spectrally different from sunlight, and varies from parlour to parlour. But intentional tanners often tan both in the sun and at several parlours.

    Frankly, I think this is about all the research I, personally, want to do. The evidence may not satisfy an epidemiologist’s quest for certainty, and I welcome their continued research interest. But it’s more than enough to convince me never to enter a tanning parlour. With due sympathy to any sunbed addicts, I’m worried about you and I think you’re not doing the smartest thing. Look after yourselves.

    The WHO paraphrases the additional risk factors from the ICNIRP report as follows:”
    * People who have skin phototypes I or II;
    * Children (i.e., less than 18 years of age);
    * People who have large numbers of nevi (moles);
    * Persons who tend to freckle;
    * Individuals who have a history of frequent childhood sunburn;
    * People who have pre-malignant or malignant skin lesions;
    * People who have sun-damaged skin;
    * Those who are wearing cosmetics. These may enhance their sensitivity to UV exposure; and
    * Persons taking medications. In this case they should seek advice from their physician to determine if the medication will make them UV-sensitive.

    (from WHO Fact sheet N°287, from http://www.who.int/mediacentre/factsheets/fs287/en/)

    NOTE: “skin phototypes I or II” means those who burn more easily than they tan.


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