Prospective survey-based study with 15,227 people in the UK, showing lower risk of COVID-19 cases with vitamin A, vitamin D, zinc, selenium, probiotics, and inhaled corticosteroids; and higher risk with metformin and vitamin C. Statistical significance was not reached for any of these. Results are subject to confounding, with only the vitamin D result fully adjusted. NCT04330599
. COVIDENCE UK.
risk of case, 6.8% lower, RR 0.93, p = 0.77, treatment 21 of 750 (2.8%), control 425 of 14,477 (2.9%), adjusted per study, odds ratio converted to relative risk, minimally adjusted, group sizes approximated.
This study is excluded in the after exclusion results of meta
significant unadjusted confounding possible.
Holt et al., 3/30/2021, prospective, United Kingdom, Europe, preprint, 31 authors.
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.