Association Between Vitamin D Levels and Inflammatory Markers in COVID-19 Patients: A Meta-Analysis of Observational Studies
Bibliographic record
Abstract
PURPOSE: Vitamin D has immunomodulatory properties that can be useful in COVID-19 patients. We performed a meta-analysis of observational studies to analyze the association of vitamin D levels with the inflammatory markers in COVID-19 patients. METHODS: We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Database of Systematic Reviews, and ClinicalTrial.gov for any relevant studies with comparison data reporting vitamin D levels and inflammatory markers in COVID-19 patients. A literature search was conducted from December 1, 2019, to January 14, 2022. Vitamin D deficiency was defined by each individual study and ranged from <9.9 ng/mL to <30 ng/mL. The inflammatory markers of interest were interleukin-6 (IL-6), C-reactive protein (CRP), ferritin, procalcitonin, erythrocyte sedimentation rate (ESR), lactate dehydrogenase (LDH), fibrinogen and D-dimer. Weighted mean difference (WMD) and 95% confidence intervals (CIs) were pooled using random or fixed-effects models. Two independent investigators assessed study eligibility and synthesized the evidence. RESULTS: Thirty-two observational studies were included comprising of 7,771 patients ranging from 40-81 years of age with 57.1% being male. Meta-analysis showed that patients that were vitamin D sufficient (levels >30ng/mL) had statistically significant lower levels of IL-6, CRP, ferritin, LDH, fibrinogen, and D-dimer compared to vitamin D deficient group. With the highest mean difference found in ferritin (95.62; 95% CI, 33.14-158.10); P=0.003; I2=99%). No significant reductions were found in ESR (P=0.97). All inflammatory markers analyzed were higher than the normal healthy reference ranges in both groups. CONCLUSIONS: Our results suggest that low vitamin D levels are associated with increased inflammatory marker levels. Vitamin D deficiency may potentially serve as an early identifier for COVID-19 patients at high risk of developing severe inflammatory conditions as well as thrombotic complications. Randomized controlled trials should be conducted to establish a causal relationship.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.018 | 0.030 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.018 | 0.056 |
| Bibliometrics | 0.006 | 0.008 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".