| This piece is not as thorough as my vitamin D & COVID-19 review: http://agingbiotech.info/vitamindcovid19/ or its 1-page bullet-point summary: http://agingbiotech.info/vitamindcovid19facts/ A lot of words on correlation != causation without noting any of the causal evidence. Even my 1-pager highlights the obvious responses to this over-used inequality: 1. RCTs show D supplements effective against respiratory infection (Martineau BMJ'17: 25 RCTs, now updated as preprint expanded to ~40RCTs covering ~30,000 people. 2. Causal evidence D is protective against lung injury (in rats) related to ACE2. 3. D extends lifespan in worms (which don't have bones), and we all know how much of a risk factor age is for C19. [This one not in my 1pager, only the full review.] 4. The number of plausible biological mechanism arguments is very large and expanding. See Linda Benskin's excellent review for the most comprehensive review of that evidence up through mid-June. More recently, the active form has been shown to have direct action against SARS-CoV-2. 5. Causal inference model shows that D's effect on C19 is causal [Davies et al]. 6. Mendelian randomization shows that the correlations that would need to explain its data are far fetched (eg, systematic racism is worse in the US the farther north you go, by more than 5x) [De Smet et al] 7. Controlled intervention trial shows benefit from D+mag+B12 [Chuen Wen Tan et al] I don't talk about it in my reviews, but there is also a set of guidelines for when you can infer causation from observational data called Hill's criteria and one paper did apply that to D related data and the evidence so far met all the criteria. Long pieces that try to create uncertainty around vitamin D in the context of COVID-19 by repeatedly questioning the correlational data without noting any of the relevant causal evidence are far too common these days, and a bit irresponsible at this point. Karl |