It's always important to know about authors' conflicts of interest. However, in this case the results align with a lot of others related to vitamin D's effects

It's always important to know about authors' conflicts of interest. However, in this case the results align with a lot of others related to vitamin D's effects on cancer and the immune system in general. (I believe it's possible for the raw number of studies supporting a position to also be a misleading figure, but in this case I don't sense that's what's going on.) Fun fact, vitamin D was a treatment for tuberculosis before antibiotics. https://www.ncbi.nlm.nih.gov/pubmed/29804293 https://www.ncbi.nlm.nih.gov/pubmed/29804293