Hacker News new | ask | show | jobs
by persedes 37 days ago
Not in the field, but every time vitamin D studies come up I am reminded of the one that called out how current recommendations are based on faulty math (confusion on how to combine different sized studies confidence ranges ) and miss the mark significantly (and a lot of studies are based on those recommendations...)

https://pmc.ncbi.nlm.nih.gov/articles/PMC5541280/
2 comments
nostromo 37 days ago
To save people the click: the study says that the recommended vitamin D intake is much too low.
link
Etheryte 37 days ago
Honestly you don't even need to know the recommended number. In many countries you can get tested for free, and if that's not the case for you, getting tested usually costs in the ballpark of a box vitamin D supplements. Measure and only then supplement, then measure again later. You don't need to fly blind.
link
anamexis 37 days ago
A year's worth of daily 5000 IU (125 mcg) Vitamin D supplements costs approximately $15, so you could also just supplement.
link
tim-tday 37 days ago
Strangely the protective effects of vitamin d for heart disease appear NOT to be achieved through supplements. (Though the protective effects for cancer ARE)

I’m going to go out on a limb and guess that people who get outside a lot protect their health through both natural vitamin D from UV light exposure and cardiovascular exercise.

link
Etheryte 37 days ago
This approach doesn't make much sense to me. Why supplement something when you don't even know that you need it? You could make the same argument about any and every supplement and eat the whole alphabet soup every day, but that's just putting extra strain on your body.
link
anamexis 37 days ago
Well, if a study finds that nearly everyone of your skin color at your latitude is deficient, you can make an educated guess.
link
rendaw 37 days ago
This has come up several times before. It's not well cited. I read through it myself and even if the math is right, the application of the math seems incorrect.

The original data was a small number of studies with a small amount of old (1980s?) data that found a slope with so-so correlation.

The revised math finds a much smaller slope with what appears to be much worse fit to the same old data. The data was nearly horizontal before, but after the math changes it's much further away from 0.

The original study was making predictions near the data. The revision is doing massive extrapolation, far away from the range of what any of the studies tested.

I'm not a statistician, but it's not surprising to me that it's being ignored.

link