[devaboone]

I think doing an update would be great, when I have time. Just a note: the article you cited was not a randomized controlled trial. It is a meta-analysis that included only 2 small RCTs and a ton of observational studies.

The image from my post that you are referring to is looking only at RCTs. In RCTs, Vitamin D supplementation rarely shows a positive effect. This does not mean that Vitamin D supplementation is useless.

Even in my post from 2020, I mention that respiratory illness is one area that has shown a benefit of Vitamin D. Here is what I wrote:

"The areas in which meta-analyses have identified benefits from Vitamin D:

Fracture prevention in elderly nursing home residents (when also given with calcium): This is not surprising. We know that Vitamin D and calcium can prevent bone loss in severe Vitamin D deficiency. Elderly adults who are not getting outside are more likely to be severely deficient in Vitamin D, and supplements likely help.

Asthma and respiratory infection: Vitamin D seems to reduce asthma attacks in adults with mild to moderate disease, and daily or weekly Vitamin D seems to prevent acute respiratory infection in those with Vitamin D less than 10 ng/ml (25 nmol/l). There is considerable excitement around Vitamin D's potential role in Covid treatment, though we do not yet have enough evidence to make a definitive conclusion.

Cancer mortality: Vitamin D does not appear to prevent cancer, but may reduce death rates from cancer overall (when all cancers are combined) when Vitamin D is taken for several years. It is not known whether Vitamin D itself fights cancer. It could also be that individuals with cancer are more prone to developing severe Vitamin D deficiency, which leads to bone loss, fragility, and fractures, which increase mortality.

Atopic dermatitis (eczema): Vitamin D supplementation may prevent exacerbation of eczema. There are only a small number of trials, with small numbers of patients, so this requires more research."

We do have more information on Covid and Vitamin D now, and I would agree that Vitamin D was likely beneficial for some people. I would also add that I had a bunch of patients come in with high calcium because they started high-dose Vitamin D during Covid and never decreased the dose.