I've been working in heart health in 10 years and I was surprised at the magnitude of the effect here.

I hope it holds up as they move toward the final publication. Vitamin D supplementation is cheap and this could have a huge benefit.

Well, that is strange though. Because if you have such an effect, should you not include this? If macrophages are less active, perhaps infection rates go up, which can contribute to death. Perhaps not to the amount of the 52% gains mentioned here, but the website does not mention this at all whatsoever; the word "macrophages" occurs only twice on total.

> Participants in the experiment arm who stayed within 40-80 ng/mL of vitamin D had a 52% lower risk of a repeat heart attack.

The study did use supplements to get people into that range if necessary, but the important thing is to keep your Vitamin D in that range, not specifically to just take supplements.

There’s a lot of claims online that everyone’s Vitamin D is too low and we should all be taking very high dose supplements, but it’s getting exaggerated. My doctor said she’s seeing a huge number of patients coming back with excessively high Vitamin D levels after taking supplement doses recommended by influencers. It happened to me, too, with what I though was a conservative dose of Vitamin D (5K IU, not even taken every day)

So you really have to check. Even though I work indoors and wear sunscreen a lot, apparently my diet and limited sun exposure alone are sufficient for staying in this range. Others will have different results. Don’t guess!

Also remember that Vitamin D levels change slowly. Supplementation can build up and accumulate in the body over time if you’re taking too much. You want to stabilize on a dose and then check in 3-6 months. Some people get a low Vitamin D result and start taking high doses every day, then a year or two later they’re into hypervitaminosis D and have no way to clear it other than waiting for it to be processed out.