et al., Int. J. Clinical Practive,
Retrospective 104 consecutive patients tested for COVID-19 in a hospital in the UK, showing lower vitamin D and higher social deprivation associated with COVID-19 positive results.
Livingston et al., 4/2/2021, retrospective, United Kingdom, Europe, peer-reviewed, 7 authors.
risk of COVID-19 case, 50.9% lower, RR 0.49, p < 0.001, high D levels 16 of 52 (30.8%), low D levels 31 of 52 (59.6%), odds ratio converted to relative risk, >34.4nmol/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.