The Centrality of the Sun: Melanoma - Another Snippit from the upcoming 25(OH)D Seminar

Here's a little preview of a rather interesting fundamental; I have lots of papers (from the past decade particularly) that capture this reality, but this one is well-executed and full of detail, summarized slide below.  Not that we are not talking about the common-or-garden skin cancers (basal or squamous cell) - the latter are very resolvable with prompt attention, and are often described as "almost cosmetic" cancers, due to the lack of metastasis observed. No, here we are talking about the real bad actor - Melanoma - and its fascinating relationship with human sun exposure.  It is reminiscent of the "Fat bad, Carb good" simplistic error during the past 5 decades, isn't it? Yet again, they fell decades ago by applying simplistic logic to a complex and counter-intuitive arena, and the impact to population health has been.....unfortunate:

Slide.JPG

And while I'm at it, here's another one we'll be discussing, a 2014 Swedish study where the highest quartile of sun exposure had approx. half the mortality rate of the lowest quartile over 15 years - and before you ask, they corrected for quite a few confounding factors too; herein lies the danger in assuming that evolution itself is an aimless and idiotic process:

Also, another misunderstanding has had profound consequences - sunscreens for decades successfully blocked the D-producing and Burn-Warning elements of UV (they blocked UVB wavelengths).  But...........high energy UVA causes massive damage, arguably much more melanoma than UVB, and it flies through the traditional screens with impunity. Now, without sunscreen, you naturally limit your exposure, and the tanning that results from it HAS the capability to block the nasty UVA - spot the disaster do you? Thus people inadvertently grilled their DNA in UVA, which is why many studies have linked higher melanoma rates to sunscreen use. I've attached one (of many) papers that realized the horror.........back in 1994:

Effect of sunscreens on UV radiation-induced enhancement of melanoma growth in mice
 

We'll go through this in more detail during the seminar - this is the tip of the proverbial iceberg.....!