Does Vitamin D protect against melanoma?
Vitamin D protects against melanoma.
We live in a time of heliophobia - fear of the sun. We are told that the sun is very dangerous and must be avoided, otherwise we will develop skin cancer.
There is no doubt that facial squamous cell cancers are the result of sun damage to pale skins, but they are easily treated and occur almost exclusively after the age of 60 years. Unfortunately they are lumped together by the media with the much more dangerous but much less common melanoma.
The diagnosis rate of melanoma has increased dramatically during the past few years, at such a rate that it can only be attributable to a change in diagnostic practice. Th death rate has remained unchanged, and so it is difficult to know the true incidence rate. Many more suspicious lesions are removed from the skin than used to be the case, part of response to an assumed epidemic.
Australia has the world’s highest diagnosis rate of melanoma with a big skin protection campaign. But the UK has a much higher death rate from melanoma, in young people also the highest in Europe.
The link between the sun and melanoma is far from clear, and is controversial among dermatologists. A recently-published UK study explores a possible link between melanoma and vitamin D. It showed that relapse-free survival improves with increasing blood levels of vitamin D.
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Those with blood levels of vitamin D greater than 25ng/ml (60nmol/L) had a considerable and significant survival advantage, 72%, over those with levels less than 15ng/ml (40nmol/L), 87%..
These blood levels are far from extreme in a UK population. We would expect many to have blood levels less than 10ng/ml (25nmol/L) but this breakdown was not shown in this study.
Also, the ideal blood level of vitamin D is now thought to be greater than 40ng/ml (100nmol/L). This is an uncommon finding in the UK but it would have been interesting to see the survival from melanoma in those with this blood level. Perhaps no patients had a blood level in this range, which would have been interesting in itself.
So we have more evidence of the protective effects of vitamin D.
Reference:
Newton-Bishop JA et al
Journal of Clinical Oncology 2009
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