Retrospective 489 patients showing 44% lower risk for COVID-19 with vitamin D sufficiency, relative risk RR = 0.56, p
Meltzer et al., 9/3/2020, retrospective, USA, North America, peer-reviewed, 6 authors.
risk of COVID-19 case, 43.5% lower, RR 0.56, p = 0.02, high D levels 39 of 317 (12.3%), low D levels 32 of 172 (18.6%), adjusted per study, >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.