Could shying away from the sun increase our risk of melanoma?

It’s a glorious warm and sunny day today in London, UK. A shadow was cast, though, by this story which appeared today in one of the UK’s national newspapers. It concerns the tragic death of a 21-year-old lady from malignant melanoma. We’re told that that the victim ‘hated the sun’ and did her utmost to protect herself from it. Yet, she still ended up succumbing to malignant melanoma. The subtext: any amount of sun is hazardous.

However, is it true that ultraviolet exposure of the skin causes malignant melanoma? I know this link is constantly referred to and alluded to, but does it stand up to scrutiny?

In 2008, the British Medical Journal ran a piece by Dr Sam Shuster (a dermatologist) in which he dissects some pertinent research regarding the link between sunlight exposure and malignant melanoma [1]. Here are some of the points made in this piece:

1. some forms of skin cancer (relatively harmless basal cell and squamus cell cancers) tend to occur in sun-exposed parts of the body, but 75 per cent of malignant melanomas do not.

2. The relationship with latitude is small and inconsistent (in other words, locations closer to the equator with more sunlight exposure do not see very significantly increased malignant melanoma incidence).

3. Malignant melanoma incidence and death from this condition are lower in individuals with increased sunlight exposure (11 studies are cited as evidence to support this).

4. Incidence of malignant melanoma is not reduced and can be increased by sunscreen use.

5. Melanoma risk associated with sunbed use is “small and inconsistent”.

6. Inducing malignant melanoma in the laboratory using ultraviolet light is difficult (in contrast to basal cell and squamus cell carcinomas).

In short, the relationship between sunlight exposure and malignant melanoma is far from clear-cut. More than this though, there is even some evidence that sunlight exposure might help protect against this condition.

It’s important, I think, to bear this in mind when reading stories like the one I link to above. The ‘sunlight at any dose is dangerous’ subtext comes from the belief that sunlight is a major cause of melanoma. This, quite frankly, appears not to be an accurate reflection of the truth. The balance of evidence suggests some protective effect. Taking this at face value, is it possible that this lady’s death was not in spite of her fear of the sun, but partly because of it?

We are faced with the very real possibility that this death was the result of general misinformation about the supposed perils of sunlight exposure.

See here for advice about how to get safe sun exposure.

References:

1. Shuster S. Is sun exposure a major cause of melanoma? No. BMJ 2008; 337:a764

25 Responses to Could shying away from the sun increase our risk of melanoma?

  1. Matt Edmundson 6 April 2011 at 2:01 pm #

    Love your common sense approach to this! I remember going to a doctor about a mole, and he told me that I had to wear sunscreen in Feb in the UK! I couldn’t believe what this guy was telling me – it was like the sun has become our arch-nemisis.

  2. Nigel Kinbrum 6 April 2011 at 3:15 pm #

    Since I started supplementing with 5,000iu/day of Vitamin D3, my skin has become more sun-burn resistant.

    See also Is Vitamin D Shooting Me in the Foot?

  3. Hans Keer 7 April 2011 at 5:33 am #

    Very good. Ditch the sunscreen and enjoy the sun with policy. Edward Gorham gave a clear lecture on the subject: http://www.cutthecarb.com/edward-gorham-on-skin-cancer-and-sunscreen/. VBR Hans

  4. rod tucker 7 April 2011 at 7:52 am #

    I think that for balance you should have mentioned that the reference you quoted was part of a yes and no debate. The yes camp does provide evidence that melanoma could be caused by sun exposure.

  5. Chris 7 April 2011 at 4:23 pm #

    Almost all off life, “as we know it, Jim” revolves around the Sun in some way.

    Ours is a species evolved from progenitors who once under a forest canopy of fairly tropical latitudes. Nothing lasts forever, however. Natural and cyclical climate change caused change to habitat (contraction, recession, or migration of the forest habitat) that in turn put pressure upon progenitors to adapt to the changes to, or the contraction of, their familiar forest habitat. One hypothesis, noting that there were repeated cycles of interglacial and glacial periods, is that the process advanced to likelihood of evolving to a generalist, us.
    There came a time when our progenitors did not have the forest habitat to rely on. Not able to eat the grass, they followed an option to ‘eat the animals that grazed on the grass.’ The acquisition of the skills to cook the flesh of the animals that grazed upon the grass was one incremental factor that improved the balance of the ‘digestive’ economy. The balance of reward over effort was improved. In a transition to become habituated to more open terrain our ancestors must have spent more time out in the sun. I expect they avoided the midday sun – as only mad dogs and Englishmen don’t.
    In the migration to Eurasian latitudes our ancestors likely spent much time not under cover. The habitat would have influenced the extent and nature of the exposure they had to the sun. More recently ancestors must have spent time out of doors but enjoying, at times, the dappled light and shade of once extensive deciduous forests.

    I think the ‘primal view’ constitutes a helpful ‘litmus test’ to apply to modern analysis and interpretation. Neither view can deliver certainty, but the primal view can lend horizons from which to interpret often conflicting modern ‘science’.

    Like most of the things that suit our needs we likely need the extent and manner of our exposure to UV to be in the ‘goldilocks zone’. General concern for low vitamin D status might be an indicator that some people are on the low side of that zone.

    Rod, imo Dr Briffa was balanced and objective while the example of lazy journalism was not.

    The press is full of articles that put the needs of the press’es paymasters before the (best) interests of their readers. As spring advances to summer, keep an eye open for advertising for sun-screen, or advertising for the multiples that includes reference to offers on sun-screens.

  6. Liz Smith 8 April 2011 at 10:06 am #

    I recently read an article suggesting that one of the ingredients of sunscreen could be the one causing the skin cancer. The amount that some people paint it on I’m not surprised its having a affect on the body. Another ‘odd’ piece I read a while ago was that lots of melanomas appear on the base of the feet. Whenever we appeared on this earth, the sun would have been probably the most important vitamin/hormone the body required. Why is it that melanomas are seen in countries that use the most sunscreen, where the richest drug companies reside?

  7. Hedley Spargo 8 April 2011 at 10:29 am #

    If a doctor prescribed a very strong painkiller for a badly sprained ankle and advised that it was then safe to walk/run, our (un)common sense would tell us that was wrong.
    Our body has a sun warning system – sunburn! Sunburn tells you that you’ve overdone sun exposure, just as the agony of a sprained ankle tells you to rest it.

    Simply lathering yourself in a (expensive, high profit) chemical gunk is analgous to prescribing morphine for a sprained ankle. It simply subdues the painful signal of your natural early warning system. Moreover, it encourages extended exposure to vulnerable skin before the body has had a chance to build its natural protection melanin.

    Little and often to start stimulates the body to protect itself. Remember too, the sun in different areas has a different ‘mix’ which I presume is dependent upon the atmosphere. I’ve travelled back to UK after a few months in Spain, and suddenly burned in what I considered quite mild sunshine.

  8. John 8 April 2011 at 10:42 am #

    This has struck me before – lack of sun seems to be a signficant risk factor for melanoma. Possibly due to the likely low vitamin D levels. Whilst some melanomas are no doubt due to burning the skin in the sun, could the use of chemical sun screens actually also contribute to melanomas?

  9. Sally Seal 8 April 2011 at 12:13 pm #

    I live in Brittany, France where the weather is warmer than the UK. For the last 10 years my skin has become increasing sensitive to chemicals. I have had to change my make up and have stopped wearing sun cream as the last time I used it 7 years ago I came out in blisters on my neck and face. This makes me very cautious about what I use. I could go down the organic route but that can get expensive, so I save that purely for my face (don’t want the wrinkles!)I have adopted a continental approach to the sun, I don’t sit out or work in the sun between about 12pm and 3pm sometimes 4pm unless in the shade. As a result I get a gentle natural tan that appears quite quickly as my skin has adapted and never look like lobster.

  10. Jane Muscat 8 April 2011 at 1:10 pm #

    My uncle was died of melanoma in his fiftys and he always used to go to swim after 5o’clock being afraid of the sun.Further studies showed that it was caused by drinking a lot of homemade wine,which if not done properly is very dangerous to drink ,and he used to rebuild tyres without wearing a protection mask.

  11. Free Forester 8 April 2011 at 3:04 pm #

    I don’t like the fact that many items of skin-care and/or make-up contain sun protection. I don’t know if this is necessary or not.

  12. Feona 8 April 2011 at 5:00 pm #

    No way will I use cream or make-up with any kind of SPF in it. As a fair-skinned blue-eyed person I was advised to avoid the sun and ended up with a Vit D deficiency, which probably contributed to my osteoporosis. The solution is surely to use your common sense – if you feel too hot or uncomfortable in the sun, get out of it for a bit, otherwise – enjoy! BTW I’m now back in the sunshine and also taking 800 iu p.d. Vit D3. 5,000 iu is a bit high though, surely?

  13. Debra 8 April 2011 at 5:50 pm #

    I object that it is hard to find cosmetics and moisturizers for my face that exclude sunscreen. I do not want sunscreen in these products I put on my face! I feel that if I want to use sunscreen, then I will use it.

  14. Frederica Huxley 8 April 2011 at 7:38 pm #

    There was an interesting graph that I saw a couple of years ago, plotting the rise of melanomas with the introduction and sales of – increasingly higher SPF – sunscreens in Connecticut from the 1960′s.

  15. Radiant Lux 8 April 2011 at 8:56 pm #

    I have read that sun exposure is more harmful when eating vegetable oils that throw off the omega3:omega6 balance. The article said people can withstand more sun exposure when eating healthy oils and fats. omega-6 fats stimulate
    the development and progression of a range of human cancers, including melanoma, while
    omega-3 fats inhibit it.

  16. Julie de Burgh 9 April 2011 at 9:09 am #

    If someone has had basal cell and or squamus cell cancers are they more prone to developing melanoma?

  17. Mike T 9 April 2011 at 11:00 am #

    Yes, no, and maybe… I’d be curious to see what other reports on the matter have surfaces in the last 3 years. Or maybe the one mentioned was so conclusive that further testing was deemed unwarranted. I guess I’ll just sort through what’s been published in the last number of years until I find something supportive of whatever side of the fence I’ve decided to stand on today.

    For what it’s worth, I love the sun, dislike chemical latherings, and actively cover up when I feel that an overdose of solar radiation is imminent.

  18. Chris 11 April 2011 at 3:19 am #

    E F Schumacher observed that there are two types of science; “one being the science of knowledge and the other being the science of manipulation.”

    There is undoubtedly some excellent and virtuous science about but even the very best of ‘scientific beliefs’ held aloft and revered today will come to be modified, or even cast aside, at some point in the future. History, even the history of science, ought to teach us the folly in elevating science and empiricism to a level of status comparable with religion because the history of science is littered with instances of the need to modify once revered science.

    Empiricism, as Ben Goldacre has lucidly conveyed, can be practised with a slavish and mistaken faith in statistics in which ‘something’ can be lost or cast aside. Often ‘wisdom’ is that ‘something’ that becomes the casualty.

    Empiricism, at times the basis of great reasoning, seems also to be one foundation upon which the science of manipulation is propagated. Nothing rewards the promotion of the science of manipulation more than does the nature, attributes, and incentives afforded by ‘money’.

    Dr Briffa, the way you approached this topic advanced a thought in my own mind. Thinking in fairly open terms about the advance of ‘modern’ illness(es) in the populations of the developed world I was directed to wonder if the rise in incidence of certain conditions comes about not so much in spite of the ‘science’ but partly because of it.

    Einstein was wise enough to observe that the great challenges of our times will not be solved if the level of our thinking remains simply at the level at which it was set when we created them. Einstein was wise enough to recognise the biggest of humanities challenges’ are indeed self-made.

    Einsteins’ observation alone is profound enough but in order to really comprehend the profundity there is something I could not recommend enough. That something is for an individual to trouble to become familiar with the nature, attributes, and incentives afforded by money. After such trouble the wisdom in an observation by Linnaeus so far back as 1763 is revealed in great profundity:

    “Natures economy shall be the base for our own, for it is immutable, and ours is secondary.”

  19. Nigel Kinbrum 11 April 2011 at 6:14 pm #

    Feona said:
    BTW I’m now back in the sunshine and also taking 800 iu p.d. Vit D3. 5,000 iu is a bit high though, surely?
    5,000iu/day is 50% of what the skin can produce in one day. See Vitamin D

    And don’t call me Shirley! ;-D

  20. Jaerou Kim 18 April 2011 at 2:11 pm #

    Thank you for your valuable post. We have decided to share it with our global physician audience at PhysicianNexus.com: http://physiciannexus.com/forum/topics/could-shying-away-from-the-sun

    Jaerou Kim
    Team Member
    http://www.PhysicianNexus.com
    Physicians Comparing Treatments Worldwide

  21. Alan Metchem 24 April 2011 at 7:29 pm #

    I’d be interested in anyone’s comments about this article and vitiligo, where sun burn can happen very quickly. How can a balance be achieved between a sensible amount of sun light, and sunburn?

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