et al., Clinical Nutrition (Edinburgh, Scotland), doi:10.1016/j.clnu.2020.10.055 (Peer Reviewed)
Prospective cohort study of 129 adult hospitalized COVID-19 patients finding patients with vitamin D levels >20ng/mL had increased mortality after adjustment. This study does not account for the risk of having a serious enough case to be hospitalized, and adjustments for factors correlated with vitamin D levels could obscure a potential association with vitamin D levels.
Cereda et al., 11/1/2020, prospective, Italy, Europe, peer-reviewed, 13 authors.
risk of death, 120.0% higher, RR 2.20, p = 0.04, high D levels 10 of 30 (33.3%), low D levels 24 of 99 (24.2%), odds ratio converted to relative risk, >20ng/mL.
risk of ICU admission, 86.7% lower, RR 0.13, p = 0.59, high D levels 0 of 30 (0.0%), low D levels 5 of 99 (5.1%), continuity correction due to zero event (with reciprocal of the contrasting arm).
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.