et al., Journal of the Endocrine Society, doi: 10.1210/jendso/bvab048.567 (Peer Reviewed)
Retrospective 129 hospitalized patients with vitamin D levels measured within 90 days prior to admission, showing lower, but not statistically significant, risk of severe cases with vitamin D supplementation among patients with levels <20ng/mL or <12ng/mL. For <30ng/mL, lower (but not statistically significant) risk was seen overall but not for ≥50,000IU (the sample size is not given, it may be extremely small for this case). Only minimal details for <30ng/mL are provided, and no details for <20ng/mL or <12ng/mL are provided. The potential effect of supplementation on the risk of a case severe enough for hospitalization is not included.
Levitus et al., 5/3/2021, retrospective, USA, North America, peer-reviewed, 9 authors, dosage varies.
risk of COVID-19 severe case, 30.8% lower, RR 0.69, p = 0.25, treatment 65, control 64, odds ratio converted to relative risk, ≥1.
risk of COVID-19 severe case, 40.0% lower, RR 0.60, p = 0.15, treatment 65, control 64, odds ratio converted to relative risk, ≥5.
risk of COVID-19 severe case, no change, RR 1.00, p = 0.92, treatment 65, control 64, odds ratio converted to relative risk, ≥50.
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.