Retrospective 2,102 rheumatology patients in Spain showing lower, but not statistically significant, cases with vitamin D supplementation. Details of vitamin D supplementation are not providied - other patients may have also independently taken vitamin D.
Blanch-Rubió et al., 10/20/2020, retrospective, Spain, Europe, peer-reviewed, 10 authors, dosage not specified.
risk of COVID-19 case, 8.0% lower, RR 0.92, p = 0.68, treatment 62 of 1,303 (4.8%), control 47 of 799 (5.9%), adjusted per study.
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.