Retrospective 1,634 patients tested for SARS-CoV-2 in Brazil, showing vitamin D levels <30ng/mL associated with greater odds of a positive SARS-CoV-2 test in patients older than 49 years.
Ribeiro et al., 8/5/2021, retrospective, Brazil, South America, peer-reviewed, 8 authors.
risk of COVID-19 case, 50.5% lower, RR 0.50, p = 0.01, >30ng/mL, multivariate, RR approximated with OR.
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.