Retrospective 75 COVID-19 hospitalized pediatric patients in Turkey and 80 healthy controls, showing significantly lower vitamin D levels in COVID-19 patients.
Alpcan et al., 8/10/2021, retrospective, Turkey, Europe, peer-reviewed, 3 authors.
risk of COVID-19 case, 44.6% lower, RR 0.55, p < 0.001, high D levels 42 of 108 (38.9%), low D levels 33 of 47 (70.2%), >20ng/mL.
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.