Retrospective 335 patients in China compared to 560 matched controls showing significanlty lower risk of severe COVID-19 with vitamin D sufficiency (>=30 nmol/L) OR 0.37, p
Luo et al., 11/13/2020, retrospective, China, Asia, peer-reviewed, median age 56.0, 5 authors.
risk of disease progression, 63.0% lower, RR 0.37, p = 0.01, high D levels 335, low D levels 560, >30nmol/L.
Effect extraction follows pre-specified rules
prioritizing more serious outcomes. For an individual study the most serious
outcome may have a smaller number of events and lower statistical signficance,
however this provides the strongest evidence for the most serious outcomes
when combining the results of many trials.