Retrospective cohort study of 487 patients finding that lower vitamin D levels is associated with more severe cases as measured by affected lung segments and increased hospitalization time for COVID-19 positive patients, and that lower vitamin D levels increases COVID-19 PCR+ cases.
Demir et al., 1/29/2021, retrospective, Turkey, Europe, peer-reviewed, 3 authors.
risk of COVID-19 severe case, 89.3% lower, RR 0.11, p < 0.001, high D levels 13, low D levels 99, ratio of the mean number of affected lung segments, >30ng/ml vs. <=10ng/mL.
hospitalization time, 87.1% lower, relative time 0.13, p < 0.001, high D levels 13, low D levels 99, >30ng/ml vs. <=10ng/mL.
risk of COVID-19 case, 24.2% lower, RR 0.76, p = 0.18, high D levels 13 of 31 (41.9%), low D levels 99 of 179 (55.3%), >30ng/ml vs. <=10ng/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.