et al., Journal of the American College of Nutrition, doi:10.1080/07315724.2020.1869626 (Peer Reviewed)
Retrospective 437 mostly serious condition (85% hospitalized) patients in New York, showing vitamin D deficiency associated with increased likelihood of oxygen support, but no association with mortality and hospitalization. Multivariate analysis excluded variables with p > 0.2 in univariate analysis. Adjustment for factors correlated with vitamin D may obscure the effect of vitamin D levels.
Gavioli et al., 2/19/2021, retrospective, USA, North America, peer-reviewed, 4 authors.
risk of death, 4.7% higher, RR 1.05, p = 0.83, high D levels 80 of 260 (30.8%), low D levels 52 of 177 (29.4%), >20ng/ml.
risk of death, 44.8% lower, RR 0.55, p < 0.001, high D levels 102 of 376 (27.1%), low D levels 30 of 61 (49.2%), >10ng/ml.
risk of oxygen therapy, 55.2% lower, RR 0.45, p < 0.001, high D levels 127 of 260 (48.8%), low D levels 116 of 177 (65.5%), adjusted per study, >20ng/ml, multivariate.
risk of hospitalization, 3.6% lower, RR 0.96, p = 0.41, high D levels 218 of 260 (83.8%), low D levels 154 of 177 (87.0%), >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.