et al., Int. J. Infect. Dis.,
Nutrient study of 50 hospitalized COVID-19 patients in South Korea showing that 76% of patients were vitamin D deficient. Comparison with 150 matched controls showed a higher probability of cases with vitamin D deficiency.
Im et al., 8/11/2020, retrospective, South Korea, Asia, peer-reviewed, 6 authors.
risk of COVID-19 case, 73.1% lower, RR 0.27, p = 0.003, high D levels 98, low D levels 102.
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.