Large observational population study showing a strong association between vitamin D deficiency and COVID-19.
Israel et al., 9/10/2020, retrospective, population-based cohort, Israel, Middle East, preprint, 8 authors.
risk of COVID-19 case, 21.3% lower, RR 0.79, p < 0.001, high D levels 2601 of 32712 (8.0%), low D levels 5011 of 39485 (12.7%), adjusted per study, odds ratio converted to relative risk, multivariable >75 nmol/L vs. <30 nmol/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.