et al., J. Nutr. Health Aging, doi:10.1007/s12603-020-1479-0
Retrospective 149 COVID-19 patients, 69.1% with vitamin D deficiency, showing lower vitamin D levels associated with higher mortality.
Karahan et al., 10/5/2020, retrospective, Turkey, Middle East, peer-reviewed, 2 authors.
risk of death, 82.5% lower, RR 0.17, p < 0.001, high D levels 5 of 46 (10.9%), low D levels 64 of 103 (62.1%), >20nmol/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.