Table 1 Basic characteristics of included articles reporting the association between vitamin D and COVID-19 infection and death, effect of vitamin D supplement on clinical outcomes in patients with COVID-19
Author, publication year, country | Study design, Follow up | Source of patients | Sample size (N) | Mean age (years), male | Definition of Vitamin D exposure | Expose level of vitamin D | OR (95% CI)a | Adjustments for confounders |
Prospective cohort study | UK Biobank | 341,484 | 49, 48% | Conducted between 2006 and 2010 | Per 10 ng/ml < 20 ng/ml > 20 ng/ml Per 10 nmol/L < 20 ng/ml > 20 ng/ml | COVID-19 infection 1.00 (0.89–1.12) 1.06 (0.89–1.26) Ref Death 0.95 (0.79–1.15) 1.02 (0.75–1.38) Ref | Age, sex, ethnicity, month of assessment, Townsend deprivation quintile, household income, BMI category, smoking status, diabetes, systolic blood pressure, diastolic blood pressure, self-reported health rating, and long-standing illness, disability or infirmity | |
Retrospective cohort study | University of Chicago Medicine | 498 | 49,25% | Within 1 year before their first COVID-19 tests | < 20 ng/ml > 20 ng/ml | COVID-19 infection 1.77 (1.12–2.81) Ref | Age, sex, ethnicity, race, employee status. Hypertension, DM, chronic pulmonary disease, pulmonary circulation disorders, depression, CKD, liver disease, comorbidities with immunosuppression, BMI | |
Radujkovic,2020, Germany [5] | Retrospective cohort study | Medical university Hospital of Heidelberg | 185 | 60,51% | At the time of admission and SARS-CoV-2 testing | < 20 ng/ml > 20 ng/ml | Death 11.27 (1.48–85.55) Ref | Age, gender, and any comorbidities |
Charoenngam,2021, US [14] | Retrospective cohort study | Boston University Medical Center | 287 | 62,47% | Measured at within 48 h after admission | < 30 ng/ml > 30 ng/ml | Death Ref 0.62 (0.28–1.41) | Age, sex, BMI, insurance, race, smoking, alcohol drinking, type 2 DM, hypertension, dyslipidemia, CAD, cerebrovascular disease, COPD, asthma, CKD, ESRD, malignancy, HIV infection, and heart failure. |
Carpagnano, 2020, Italy [13] | Retrospective cohort study | Hospital Policlinic of Bari | 42 | NA | At admission | < 10 ng/ml > 10 ng/ml | Death 5.68 (1.14–28.97) Ref | Age, higher levels of creatinine, troponin, and IL-6 |
Katz D,2020, US [18] | Retrospective cohort study | UF health centers | 887 | NA, NA | October 1, 2015, through June, 30, 2020, for vitamin D deficiency | < 20 ng/ml > 20 ng/ml | COVID-19 infection 2.27 (1.79–2.87) Ref | Age, sex, malabsorption, PA, dental diseases, race, periodontal disease status, DM, obesity |
Kaufman, 2020, US [19] | Retrospective cohort study | National clinical laboratory | 191,779 | 54, 22% | Most recent vitamin D level | Per 10 ng/ml | COVID-19 infection 0.85 (0.84–0.86) | Male, northern and central latitudes, predominately black non-Hispanic zip codes, and predominately Hispanic zip codes |
Angelidi,2020, US [22] | Retrospective cohort study | 2 tertiary academic medical centers | 144 | 66, 64% | Hospital personnel at Regular intervals | < 30 ng/ml > 30 ng/ml Per 10 ng/ml | Death 8.33 (1.6–50) Ref 0.54(0.35–0.82) | Age, BMI, ARB or ACEI, in-hospital drug treatment, CRP, smoking, heart failure, CAD, diabetes, hypertension, C-reactive protein level, and corticosteroids |
De Smet,2021, Germany [15] | Retrospective cohort study | AZ Delta General Hospital | 186 | 69,58% | Measured in patients with COVID-19 on admission and within 24 h | < 20 ng/ml > 20 ng/ml | Death 3.87(1.30–11.55) Ref | Age, higher CT severity score, presence of chronic lung |
AlSafar, 2021, Australia [12] | Retrospective cohort study | Abu Dhabi, or Rashed hospital in Dubai. | 464 | 46.6,80% | At recruitment | < 20 ng/ml > 20 ng/ml | Death 1.71 (0.66, 4.43) Ref | Age, sex, and comorbidities, BMI |
Karahan, 2021, Turkey [17] | Retrospective cohort study | Health Sciences University | 149 | 64, 54% | NA | Per 10 ng/ml | Death 0.93(0.88–0.98) | Age, smoking, hyperlipidemia, DM, CKD, Chronic AF, congestive heart failure, acute kidney injury, CRP, lymphocyte count, white blood cell count, serum albumin |
Author, publication year, country | Design | Sample size (male%); mean age(years) | Number of participants in intervention and control groups | 25(OH)D assay | Mean baseline 25(OH)D concentrations, nmol/L (SD) | Oral dose of vitamin D in the intervention group | Control group | Outcome |
Murai,2021, US [20] | Multicenter double-blind RCT | 240(56),56.3 | intervention = 120; control = 120 | NA | 21.0 (10.2) 20.6 (8.1) | Single dose of 200,000 IU | Placebo | Death Admission to ICU |
Castillo,2020, Spain [16] | Signal center RCT | 76(59%),53.0 | intervention = 50; control = 26 | NA | NA | Single dose of oral calcifediol (0.532 mg) | Without Calcifediol treatment | Death Admission to ICU |