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Regular use of Vitamin D supplement is associated with fewer melanoma cases

pubmed.ncbi.nlm.nih.gov

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Re: Regular use of Vitamin D supplement is associated with fewer melanoma cases

#91

Post by brianmcc »

HPsquared wrote: post #42

Use of vitamin D supplement is also probably correlated with sunscreen use. That is, health-conscious people use both.

I don't know; vitamin D supplements may be mostly advised in places where there just isn't enough sun.

In Scotland we get insufficient sunshine to produce natural vitamin D for around 6 months of the year, and there's discussion about whether everyone should be supplementing to the point it's been mooted as an addition to the water supply.

That's relevant because nobody uses sun screen during those months. I wouldn't expect any kind of correlation through sheer lack of use.

Re: Regular use of Vitamin D supplement is associated with fewer melanoma cases

#92

Post by hn_throwaway_99 »

hombre_fatal wrote: post #85
hn_throwaway_99 wrote: post #49

Earlier quoted context omitted.

> The most plausible reason is that the scientific peer-reviewed result is correct, not the tiring "correlation does not imply causatian" commenter on HN who at most skimmed the paper. Quite the odd take given the last sentence in the abstract of this paper is essentially "correlation is not causation": > In conclusion, regular use of vitamin D associates with fewer melanoma cases, when compared to non-use, but the c…

They could be just saying they don’t know why.

Which is literally the exact same thing as "correlation is not causation".

Re: Regular use of Vitamin D supplement is associated with fewer melanoma cases

#93

Post by aiisjustanif »

rcme wrote: post #80
kixiQu wrote: post #54

Earlier quoted context omitted.

Or, at least, a safer assumption: it's worth checking to see what they said about it before publicly speculating. And indeed, it seems they did survey for sun exposure and include it in their analysis, and they caveat a lot of their references to other work in their introduction noting where other studies didn't . https://www.naturalhealthresearch.org/wp-content/uploads/202...

Ok but they tried to control for sun exposure just by asking how much sun exposure have you gotten in your life? A little or a lot (paraphrasing)? The issue with this is that the amount of vitamin D someone might take is correlated with how much sun exposure is available. And the amount of available sun exposure can impact what is considered a little / a lot to each person.

Read the methods section of the study.

> The issue with this is that the amount of vitamin D someone might take is correlated with how much sun exposure is available. And the amount of available sun exposure can impact what is considered a little / a lot to each person.

That could be case but not necessarily in this study.

Re: Regular use of Vitamin D supplement is associated with fewer melanoma cases

#95

Post by cheald »

globular-toast wrote: post #89
chrisco255 wrote: post #63

Earlier quoted context omitted.

Vitamin D is a fat soluble vitamin, so of course it is being stored in fatty tissues in the body. Where else would it be stored? Your blood stream is not a storage mechanism but a transportation mechanism. Daily Recommend Values for basic nutrients aren't the same as medicinal dosages. Nobody ever gets Daily Recommended Values for all the essential nutrients anyways, and many of them are regularly exceeded by a singl…

So what if the vitamin D is being accumulated in fat and the blood can only carry so much regardless of how much is accumulated in fat? Seems dangerous to keep taking more and more at a really high dose doesn't it?

Toxicity is defined by serum levels, and is at around 100 ng/mL. My last labs put me at 39 ng/mL, and I've been taking vitamin D for years. Under 30 is considered insufficient, under 20 is deficient.

I mean, yeah, sure, don't chug bottles of the stuff without measuring for years on end, but you have to take a lot to hit toxicity levels. And periodic bloodwork to keep an eye on numerous metrics is a generally good idea anyhow.

Re: Regular use of Vitamin D supplement is associated with fewer melanoma cases

#97

Post by fatfingerd »

fsh wrote: post #10

I can only read the abstract, but this doesn't look very solid at all. It's a self-reported non-randomized study, and an absurdly large number of participants has had some type of skin cancer (184 out of 276). This makes the results extremely susceptible to selection bias.

I think by "at risk" they mean they are doing an intentional selection bias on probable skin conditions and it really isn't meant for conclusions..

Re: Regular use of Vitamin D supplement is associated with fewer melanoma cases

#98

Post by amenhotep »

yesbut wrote: post #86
amenhotep wrote: post #74

Earlier quoted context omitted.

The neat thing about vitamin D synthesis in the skin is that it stops once there's enough of it - it is literally impossible to overdose on vitamin D through sun exposure. So, there's a ceiling that makes "must be higher in sunny regions" far from obviously true!

What happens to unused vitamin D consumed from supplementation?

That gets stored in the fat. Overdose through ingestion is a thing, our bodies aren't so smart about that; it's skin synthesis specifically that limits itself.

Re: Regular use of Vitamin D supplement is associated with fewer melanoma cases

#99

Post by Spooky23 »

mlinhares wrote: post #78
Spooky23 wrote: post #71

Earlier quoted context omitted.

Keep in mind that people from Finland are more likely to have skin that makes them particularly vulnerable to Melanoma. A loved one is fighting this right now - if something simple like supplements, dietary practices or drug development could reduce the risk, it could potentially prevent alot of suffering. Even if it doesn’t work, perhaps it’s a line of inquiry with some value.

They could at least try to include white people in places where there is more sunlight, both my mom and my wife are white (my mom would likely be at home at a Nordic country, her family is full of redheads) and they both developed melanoma in northeastern Brazil, albeit they were found out quickly and did not cause much trouble. Not even trying to consider the confounding variables is really sad.

Sure.

Honestly I’m don’t feel qualified to evaluate the study.

It attracted my attention because the risk factors for melanoma are different than other skin cancers. A smaller number of severe sunburn incidents is correlated with melanoma while ongoing exposure to more moderate sunlight drives other cancers. We already know that the palest skin types (ie your redhead relatives, etc) are at higher risk than even slighter less pale people.

I hope there’s more research and we learn more about ways to help bend the risk curve.

Re: Regular use of Vitamin D supplement is associated with fewer melanoma cases

#100

Post by probably_a_gpt »

ijlx wrote: post #77
EdwardDiego wrote: post #72

Earlier quoted context omitted.

I'm pretty sure XKCD created a name for this, if no-one is replying, give a horribly wrong solution to nerd snipe someone to put the time in to giving a correct solution.

The irony here is not lost on me, but it's Cunningham's Law (apocryphally named after Ward Cunningham, the creator of the first wiki software).

You were supposed to say it was greensupun’s 10th or something.
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