Effect of Cholecalciferol Supplementation on the Clinical Features and Inflammatory Markers in Hospitalized COVID-19 Patients: A Randomized, Open-Label, Single-Center Study

Vitamin D: A Nutraceutical Supplement at the Crossroad Between Respiratory Infections and COVID-19

Even though in mid-2023 the World Health Organization declared the end of the public health emergency of international concern status for COVID-19, many areas of uncertainty about SARS-CoV-2 infection pathophysiology remain. Although in the last 4 years pharmaceutical industries widely invested in the development of effective antiviral treatments and vaccines, large disparities in their availability worldwide still exist, thus fostering the investigation of nutritional supplements as adjuvant therapeutic approaches for disease management, especially in resource-limited settings. During the COVID-19 pandemic, vitamin D has been widely used as an over-the-counter solution to improve disease evolution, thanks to its known immunomodulatory and anti-inflammatory actions. Ecological and observational studies support a relationship between hypovitaminosis D and COVID-19 negative outcomes and, according to this evidence, several research groups investigated the role of vitamin D supplementation in protecting from SARS-CoV-2 infection and/or improving disease evolution. This narrative review is intended to offer insights into the existing data on vitamin D's biological effects in respiratory infections, especially in COVID-19. Furthermore, it will also offer a brief overview of the complex interplay between vitamin D and vaccine-elicited immune response, with special attention to anti-COVID-19 vaccines.

[Vitamin D deficiency in overweight patients: current strategies and practical aspects]

On September 27, 2024, a discussion-based working meeting on the issue of vitamin D deficiency in patients with overweight and obesity was held in Vladikavkaz.The meeting aimed to evaluate the relationship between vitamin D deficiency, overweight, and associated comorbidities, as well as to explore modern strategies and practical approaches for managing such patients in endocrinology practice. The resolution of the meeting was developed by its participants, comprising leading endocrinologists.

Vitamin D, acute respiratory infections, and Covid-19: The curse of small-size randomised trials. A critical review with meta-analysis of randomised trials

BACKGROUND

Randomised trials conducted from 2006 to 2021 indicated that vitamin D supplementation (VDS) was able to prevent severe COVID-19 and acute respiratory infections (ARI). However, larger randomised trials published in 2022 did not confirm the health benefits of VDS in COVID-19 patients.

OBJECTIVE

To examine through a systematic review with meta-analysis the characteristics of randomised trials on VDS to COVID-19 patients and admission to intensive care unit (ICU), and of randomised trials on VDS for the prevention of ARI.

METHOD

A systematic search retrieved randomised trials on VDS to COVID-19 patients and admission to ICU. Data on VDS and ARI were extracted from the meta-analysis of Jolliffe et al. 2021. Groups were formed including trials with total numbers of patients below or above the median size of all trials. The associations between VDS vs no VDS, and admission to ICU were evaluated using random-effects models from which summary odds ratios (SOR) and 95% confidence intervals (CI) were obtained. Meta-analyses were done for all trials and for each group of trials, which allowed testing a possible effect modification of trial size. Publication bias was assessed using the Louis-Furuya-Kanaruori (LFK) index (no bias if index between -1 and +1) and the trim and fill method.

RESULTS

Nine trials on VDS for preventing admission to ICU were identified, including 50 to 548 patients. The summary odds ratio (SOR) was 0.61 (95% CI: 0.39-0.95) for all trials, 0.34 (0.13-0.93) for trials including 50 to <106 patients and 0.88 (0.62-1.24) for trials including 106 to 548 patients (interaction p = 0.04). The LFK index was -3.79, and after trim and fill, the SOR was 0.80 (0.40-1.61). The SOR for the 37 trials on VDS for ARI prevention included 25 to 16,000 patients. The SOR was 0.92 (0.86-0.99) for all trials, 0.69 (0.57-0.83) for trials including 25 to <248 patients and 0.98 (0.94-1.03) for trials including 248 to 16,000 patients (interaction p = 0.0001). The LFK index was -3.11, and after trim and fill, the SOR was 0.96 (0.88-1.05).

CONCLUSION

Strong publication bias affected small randomised trials on VDS for the prevention of severe COVID-19 and of ARI. Systematic reviews should beware of small-size randomised trials that generally exaggerate health benefits.

A narrative review focusing on randomized clinical trials of vitamin D supplementation for COVID-19 disease

Current evidence is inconsistent on whether vitamin D supplementation can prevent COVID-19 infection or improve its clinical outcomes. To better understand and look into the issue, we went through the background knowledge of COVID-19 and vitamin D, searched in Pubmed [by using key words in the title containing "randomized clinical trial", "COVID-19", and "vitamin D (25-hydroxyvitamin D, or cholecalciferol, or calcidiol, or calcifediol) supplementation"] for publications of studies on vitamin D/supplementation in COVID-19 patients, especially those about the randomized clinical trials (RCTs). After reviewing these papers, we did a short background review of vitamin D and the pathophysiology of COVID-19, summarized the key features of the 25 RCTs in text and tabulated in a table of some of the features, commented, compared and discussed the differences between RCTs (for example, change the serum 25-hydroxyvitamin D concentration from nmol/L to ng/mL, making the comparison easier). The take-home question of the review is that serum 25-hydroxyvitamin D concentration is an important indicator of the supplementation effect of vitamin D correction but may not be reliable in predicting the supplementation effect on the clinical outcomes of COVID-19.

The Effect of Vitamin D Supplementation Post COVID-19 Infection and Related Outcomes: A Systematic Review and Meta-Analysis

BACKGROUND

Vitamin D's role in COVID-19 management remains controversial. This meta-analysis aimed to evaluate the efficacy of vitamin D supplementation in patients with SARS-CoV-2 infection, focusing on mortality, intensive care unit (ICU) admissions, intubation rates, and hospital length of stay (LOS).

METHODS

A systematic review of PubMed/MEDLINE, Scopus, Cochrane, and Google Scholar databases was conducted. Randomized controlled trials (RCTs) and analytical studies investigating vitamin D supplementation in COVID-19 patients were included. The meta-analysis was performed using STATA MP 18.5, employing random-effect or fixed-effect models based on heterogeneity.

RESULTS

Twenty-nine studies (twenty-one RCTs, eight analytical) were analyzed. Vitamin D supplementation significantly reduced ICU admissions (OR = 0.55, 95% CI: 0.37 to 0.79) in RCTs and analytical studies (OR = 0.35, 95% CI: 0.18 to 0.66). Intubation rates were significantly reduced in RCTs (OR = 0.50, 95% CI: 0.27 to 0.92). Mortality reduction was significant in analytical studies (OR = 0.45, 95% CI: 0.24 to 0.86) but not in RCTs (OR = 0.80, 95% CI: 0.61 to 1.04). Subgroup analyses revealed more pronounced effects in older patients and severe COVID-19 cases. LOS showed a non-significant reduction (mean difference = -0.62 days, 95% CI: -1.41 to 0.18).

CONCLUSIONS

This meta-analysis suggests potential benefits of vitamin D supplementation in COVID-19 patients, particularly in reducing ICU admissions. However, the evidence varies across outcomes and patient subgroups. Discrepancies between RCTs and analytical studies highlight the need for further large-scale, well-designed trials accounting for baseline vitamin D status, standardized supplementation protocols, and patient characteristics to inform clinical guidelines for vitamin D use in COVID-19 management.

Comparative analysis of COVID-19 responses in Japan and Africa: diet, phytochemicals, vitamin D, and gut microbiota in reducing mortality-A systematic review and meta-analysis

Background

As the novel coronavirus disease 2019 (COVID-19) pandemic subsides, the clinical sequelae are becoming more problematic. Interestingly, the statistical data indicate that Africa has experienced the lowest number of cases and deaths, with an unexpected phenomenon where the number of deaths from COVID-19 has not increased significantly. Several studies have investigated the relationship between diet and coronavirus. However, no systematic review/meta-analysis has conclusively linked diet (phytochemicals and vitamin D) and the gut microbiota in the context of COVID-19.

Methods

This study examined the responses to COVID-19 in Japan and Africa, formulating the following hypotheses: (1) a healthy diet is effective against COVID-19, (2) blood vitamin D levels are associated with COVID-19 mortality, and (3) COVID-19 is associated with the gut microbiota. To investigate these hypotheses, a keyword search and meta-analysis were conducted using PubMed, and each hypothesis was tested.

Results

This study found that a healthy diet, particularly rich in phytochemicals such as polyphenols and flavonoids, is effective against COVID-19. An association was detected between blood vitamin D levels and COVID-19 mortality. The gut microbiota was linked to COVID-19 and its amelioration. These findings may have significant implications for not only understanding COVID-19 but also future prevention of pneumonia.

Efficacy of vitamin D supplementation in the treatment of patients with COVID-19: a systematic review and meta-analysis of randomized controlled trials

Context

COVID-19 has substantial effects on respiratory health and overall well-being. Recent studies suggest vitamin D as a potential treatment, but the results are inconclusive.

Objective

The authors conducted a systematic review of randomized controlled trials (RCTs) to examine the link between vitamin D and patients with COVID-19.

Data sources

The authors searched electronic databases PubMed, Cochrane, CINAHL, EMBASE and Google Scholar from their inception till August 2023.

Study selection

Inclusion criteria used in our systematic review include: (1) patients who tested positive for COVID-19, (2) intervention was vitamin D supplementation, (3) the comparator was either a placebo, standard care of treatment, or, no treatment, (4) at least one of the clinical outcomes of interest were investigated, (5) study design being RCTs.

Data extraction

Two independent reviewers manually extracted information from selected articles, including study characteristics, patient characteristics, and the primary outcomes: all-cause mortality, ICU and hospital stay length and secondary outcomes: mechanical ventilation, supplemental oxygen, ICU admission, and adverse events. Risk ratios or mean differences and 95% CIs were calculated using a random-effects model.

Data synthesis

The authors' analysis included 14 RCTs with 2165 patients. Vitamin D significantly reduced ICU admissions and lowered the need for mechanical ventilation compared to placebo. However, it did not significantly affect hospital stay length, ICU stay length, mechanical ventilation duration, mortality, or the need for supplemental oxygen.

Conclusion

Vitamin D does not significantly improve certain clinical outcomes, such as hospital and ICU stay length, for patients with COVID-19. However, it still may be significantly beneficial in decreasing the burden on intensive care services.

Effect of vitamin D supplementation on clinical outcomes in adult patients with COVID-19: A GRADE-assessed systematic review and meta-analysis of randomized controlled trials

The COVID-19 pandemic has emerged as a major global health crisis. Vitamin D, a crucial fat-soluble vitamin, has been recommended for COVID-19 patients, though evidence of its effectiveness is inconsistent. This systematic literature review and meta-analysis aimed to evaluate the impact of vitamin D supplementation on COVID-19-related outcomes. A comprehensive search was conducted across PubMed, Scopus, Web of Science, Embase, and Cochrane databases. Primary outcomes included mortality and hospital length of stay, while secondary outcomes encompassed C-reactive protein (CRP), ferritin, D-dimer, hemoglobin (Hb) concentrations, and lymphocyte, neutrophil, and platelet counts. Data analysis was performed using Stata™ Version 14. A total of 16 trials were analyzed. The meta-analysis revealed that vitamin D supplementation significantly reduced hospital length of stay (mean difference = -1.16; 95% confidence interval [CI]: -2.23, -0.09; p = .033) with significant heterogeneity (I2 = 69.2%, p = .002). Subgroup analysis showed a more pronounced reduction in studies with vitamin D dosages ≤10 000 international units (IU) (mean difference = -1.27; 95% CI: -1.96, -0.57; p < .001) and in patients over 60 years old (mean difference = -1.84; 95% CI: -2.53, -1.14; p < .001). Additionally, vitamin D significantly reduced CRP concentrations in older adults (>60 years) (mean difference = -1.13; 95% CI: -2.07, -0.18; p = .019). No significant changes were found in ferritin, D-dimer, Hb concentrations, or in lymphocyte, neutrophil, and platelet counts (p > .05). In conclusion, while vitamin D supplementation did not significantly affect most COVID-19-related biomarkers, however, it reduces the length of hospital stay.

Effect of vitamin D3 on antiphospholipid antibodies in hospitalized patients with moderate to severe COVID-19

OBJECTIVE

To investigate the effect of a single oral dose of 200,000 IU of vitamin D3 on antiphospholipid antibodies in hospitalized patients with moderate to severe COVID-19.

METHODS

This is a post-hoc, exploratory analysis from a double-blind, placebo-controlled, randomized clinical trial performed in two centers in Sao Paulo, Brazil. Hospitalized patients with COVID-19 were randomly assigned to receive either vitamin D3 (n = 97) or placebo (n = 97). In this post-hoc analysis, the endpoints were titers and frequency of anti-β2-Glycoprotein-I (aβ2-GP) and Anticardiolipin (aCL) antibodies [Immunoglobulin G, M and A (IgG, IgM and IgA)].

RESULTS

Overall mean (SD) age was 55.3 (13.9) years, Body Mass Index (BMI) was 32.2 (7.1 kg/m2), and 106 participants (54.6 %) were male. There was a significant group by time interaction (p = 0.046) for frequency of aCL IgG, with increased values from baseline to discharge in the placebo group [n (%), from 13 (13.4) to 25 (25.8)] compared to the vitamin D3 [from 25 (25.8) to 29 (29.9)]. However, the frequency of aCL IgG did not change between the groups on discharge. No significant differences between vitamin D3 and placebo groups were found for any other autoantibodies.

CONCLUSION

These findings do not support the use of a single oral dose of 200,000 IU of vitamin D3 to modulate autoantibodies in hospitalized patients with moderate to severe COVID-19.

COVID-19, Nutrients and Lifestyle Eating Behaviors: A Narrative Review

BACKGROUND

COVID-19 infection, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), quickly emerged as the most significant event of the new millennium. A balanced diet seems to ensure the proper functioning of the immune system and plays a fundamental role in the prevention of viral disease, inflammation, or thrombosis. The principal aim of this secondary study was to investigate the relationship between nutrients, lifestyle eating behaviors, and SARS-CoV-2 infection.

METHODS

A narrative review was conducted in the PubMed-Medline database, analyzing primary studies.

RESULTS

Our review identified 21 relevant studies: 13 focused on vitamins, 1 on omega-3 supplementation, 1 on probiotics, and 6 on lifestyle and dietary behaviors. Vitamin supplementation has shown promise in attenuating COVID-19 symptoms and reducing mortality risk. Specifically, vitamin D has demonstrated efficacy in enhancing immune responses among patients with the disease. While preliminary evidence suggests the potential benefits of omega-3 and probiotic supplementation in improving health outcomes for COVID-19 outpatients, further research is needed to solidify these findings.

CONCLUSIONS

The lifestyle changes imposed by lockdown measures have adversely affected psychological well-being and exacerbated health issues associated with reduced physical activity and poor dietary habits.

Rise in Serum 25-Hydroxyvitamin D Levels during the COVID-19 Pandemic

With the emergence of the COVID-19 pandemic, the absence of established evidence-based treatment protocols led healthcare professionals and the public to explore experimental treatments, including high doses of vitamin D supplements. This study aimed to assess changes in serum 25-hydroxyvitamin D levels during the pandemic, employing a retrospective cohort analysis of data from Charleston Area Medical Center (CAMC). The study analyzed serum 25-hydroxyvitamin D levels in a cohort of 35,556 patients treated at CAMC in 2019, a representative pre-pandemic period, to 2021, a representative pandemic period. Our findings revealed a significant increase in mean serum 25-hydroxyvitamin D levels as compared with 2019 (37 ± 21 vs. 31 ± 15 ng/mL, p ≤ 0.001). Additionally, in 2021, there were significantly more patients exhibiting serum levels in the highest quintiles, specifically >100 ng/mL (1.6% vs. 0.2%), 75-100 ng/mL (4.6% vs. 1.2%), and 50-75 ng/mL (16.0% vs. 8.4%), p ≤ 0.001. This upsurge suggests increased intake of vitamin D supplements, potentially fueled by widespread discussions that were taking place largely on the internet regarding the efficacy of vitamin D against COVID-19. Our findings underscore the critical need for evidence-based public health messaging, especially during health crises, to prevent unnecessary health risks and ensure patient safety.

Vitamin D Metabolism Parameters and Cytokine Profile in COVID-19 Patients with Bolus Cholecalciferol Supplementation

Recent studies have demonstrated the relationship between vitamin D deficiency, infection severity and mortality from COVID-19. This study aimed to analyze the vitamin D metabolites and cytokine expression levels of COVID-19 patients who were hospitalized with bolus cholecalciferol supplementation.

MATERIALS AND METHODS

This study represents the next stage of the open-label randomized pilot conducted by the Almazov National Medical Research Centre. A total of 44 hospitalized patients, comparable in demographic, clinical, laboratory and instrumental baseline characteristics, with moderate/severe COVID-19 were included. All patients had similar doses of concomitant corticosteroid therapy. Twenty-two patients received 50,000 IU cholecalciferol on the first and eighth days of hospitalization. The serum 25(OH)D, 1,25(OH)2D and 28 plasma cytokines were estimated for each group initially and on the ninth day of hospitalization.

RESULTS

Initially, there were no differences in the 1,25(OH)2D and cytokine levels in patients with vitamin D deficiency and normal 25(OH)D. Bolus cholecalciferol therapy at a total dose of 100,000 IU led to an increase in 25(OH)D levels in hospitalized patients with COVID-19, while the levels of the active metabolite (1,25(OH)2D) did not show significant differences between the groups or in its increased level over time, regardless of cholecalciferol supplementation. Furthermore, cholecalciferol supplementation at a total dose of 100,000 IU did not affect the majority of the cytokines estimated on the ninth day of hospitalization, except for the pro-inflammatory marker IL-1b, the concentration of which was lower in the group of patients without vitamin D supplementation.

CONCLUSIONS

The 25(OH)D level was positively associated with an anti-inflammatory immune response, but cholecalciferol supplementation at a total dose of 100,000 IU did not affect the active-form vitamin D or cytokine expression levels. This fact may be explained by the impact of corticosteroid therapy, and it requires further investigation in a post-COVID-19 context.

Therapeutic effects of vitamin D supplementation on COVID-19 aggravation: a systematic review and meta-analysis of randomized controlled trials

Background

The therapeutic effects of vitamin D supplementation on Coronavirus disease 2019 (COVID-19) aggravation remain controversial and inconclusive. To probe into this contentious issue, we performed the present meta-analysis of randomized controlled trials (RCTs).

Methods

Literature published up to June 2023 was retrieved from Cochrane Library, PubMed, Web of Science and Embase. RCTs assessing mortality, intensive care unit (ICU) admission, mechanical ventilation (MV), length of hospitalization (LOH), and inflammatory markers containing C-reactive protein (CRP), D-dimer, interleukin-6 (IL-6), lactate dehydrogenase (LDH) were included. 19 RCTs were involved in the analysis and were conducted subgroup analyses on the baseline COVID-19 severity and vitamin D administration.

Results

In the severity subgroup, statistically significant effects in moderate to severe group were observed in ICU admission (OR 0.43, 95% CI 0.23, 0.80; p = 0.008), MV (OR 0.44, 95% CI 0.27, 0.72; p = 0.001) and LOH (SMD -0.49, 95% CI -0.92, -0.06; p = 0.027). In the administration subgroup, effects of ICU admission (OR 0.39, 95% CI 0.16, 0.97; p = 0.044), MV (OR 0.18, 95% CI 0.07, 0.46; p = 0.000) and LOH (SMD -0.50, 95% CI -0.96, -0.04; p = 0.034) were more pronounced in patients supplied with multiple-dose vitamin D than single-dose. Although the result of mortality showed no statistically significant effect, it indicated a reduced trend (OR 0.87, 95% CI 0.63, 1.12; p > 0.05). The results of inflammatory markers reached no statistical differences.

Conclusion

This meta-analysis revealed that moderate to severe COVID-19 patients supplied with multiple doses of vitamin D were less apt to need ICU admission, mechanical ventilation and have shorter hospital stays.

Effect of Vitamin D3 Supplementation on Severe COVID-19: A Meta-Analysis of Randomized Clinical Trials

Since the beginning of the COVID-19 pandemic, vitamin D has attracted interest due to its immunomodulatory properties. Numerous studies show a correlation between vitamin D levels and COVID-19 cases and mortality. Therefore, we conducted a meta-analysis in order to assess the relationship between vitamin D3 supplementation and COVID-19 severity. We included 13 randomized clinical trials that contained the analyzed endpoints: length of COVID-19 hospitalization, number of intensive care unit (ICU) admissions, length of stay in the ICU, number of cases requiring any supplemental oxygenation, duration of any supplemental oxygenation, number of overall mortality and number of deaths associated with COVID-19. The relative risk with 95% confidence interval (CI) and the mean difference with 95% CI were calculated to compare the effect. A random effects model was used to calculate effect sizes. Our meta-analysis showed a positive effect of vitamin D3 supplementation on ICU admission (RR = 0.73; 95% CI [0.57; 0.95], p = 0.02, I2 = 19.6%) and mortality associated with COVID-19 among patients (RR = 0.56; 95% CI [0.34; 0.91]; p = 0.02; I2 = 0%). Vitamin D3 supplementation may potentially reduce the risk of ICU admission and death associated with COVID-19.

The Efficacy of Multivitamin, Vitamin A, Vitamin B, Vitamin C, and Vitamin D Supplements in the Prevention and Management of COVID-19 and Long-COVID: An Updated Systematic Review and Meta-Analysis of Randomized Clinical Trials

This review aims to evaluate the efficacy of any vitamin administration(s) in preventing and managing COVID-19 and/or long-COVID. Databases were searched up to May 2023 to identify randomized clinical trials comparing data on the effects of vitamin supplementation(s) versus placebo or standard of care on the two conditions of interest. Inverse-variance random-effects meta-analyses were conducted to estimate pooled risk ratios (RRs) and 95% confidence intervals (CIs) for all-cause mortality between supplemented and non-supplemented individuals. Overall, 37 articles were included: two regarded COVID-19 and long-COVID prevention and 35 records the COVID-19 management. The effects of vitamin D in preventing COVID-19 and long-COVID were contrasting. Similarly, no conclusion could be drawn on the efficacy of multivitamins, vitamin A, and vitamin B in COVID-19 management. A few positive findings were reported in some vitamin C trials but results were inconsistent in most outcomes, excluding all-cause mortality (RR = 0.84; 95% CI: 0.72-0.97). Vitamin D results were mixed in most aspects, including mortality, in which benefits were observed in regular administrations only (RR = 0.67; 95% CI: 0.49-0.91). Despite some benefits, results were mostly contradictory. Variety in recruitment and treatment protocols might explain this heterogeneity. Better-designed studies are needed to clarify these vitamins' potential effects against SARS-CoV-2.

Preventive Vitamin D Supplementation and Risk for COVID-19 Infection: A Systematic Review and Meta-Analysis

Over the past few decades, vitamin D has been found to play a crucial role in bone homeostasis, muscle function, oncogenesis, immune response and metabolism. In the context of the COVID-19 pandemic, numerous researchers have tried to determine the role vitamin D might play in the immune response to the virus. The aim of this systematic review and meta-analysis is to demonstrate that preventive vitamin D supplementation can play a protective role in the incidence of COVID-19, mortality and admission to intensive care units (ICUs). A comprehensive search on the PubMed/MEDLINE, Scopus, Cochrane and Google Scholar databases was performed on 15 May 2023, and two of the authors independently screened the literature. As effect measures, we calculated the Odds Ratios with their corresponding 95% confidence intervals (ICs). The assessment of potential bias and the evaluation of study quality will be conducted independently by two researchers. Sixteen publications were selected for inclusion in the meta-analysis. Our findings indicate that vitamin D supplementation has a protective effect against the incidence of COVID-19 in RCT studies (OR 0.403, 95% IC 0.218, 0.747), in the incidence of COVID-19 in analytical studies (OR = 0.592, 95% IC 0.476-0.736) and in ICU admission (OR 0.317, 95% IC 0.147-0.680). Subsequent analyses were conducted by type of subject treated (patient/healthcare workers) and type of supplementation (vitamin D vs. placebo/no treatment or high dose vs. low dose). Our meta-analysis suggests a definitive and significant association between the protective role of vitamin D and COVID-19 incidence and ICU admission.

Pharmacological evaluation of vitamin D in COVID-19 and long COVID-19: recent studies confirm clinical validation and highlight metformin to improve VDR sensitivity and efficacy

Nearly four years after its first appearance, and having gone from pandemic to endemic, the SARS-CoV-2 remains out of control globally. The purpose of this study was to evaluate the clinical efficacy of vitamin D (VD) in COVID-19 and long COVID-19, explain the discrepancy in clinical outcomes and highlight the potential impact of metformin on VD efficacy in recent articles. Articles from January 2022 to August 2023 were selected for this review. The objective of this study was achieved by reviewing, analyzing, and discussing articles demonstrating (1) the mechanism of action of VD (2) observational or randomized clinical trials (RCTs) that support or not the beneficial clinical effects of VD in COVID-19 or long COVID. (3) genetic and non-genetic reasons for the variation in the effects of VD. Articles were collected from electronic databases such as PubMed, Scopus, MEDLINE, Google Scholar, Egyptian Knowledge Bank, Science Direct, and Cochrane Database of Systematic Reviews. Twenty three studies conducted in vitro or in animal models indicated that VD may act in COVID-19 through protecting the respiratory system by antimicrobial peptide cathelicidins, reducing lung inflammation, regulating innate and adaptive immune functions and up regulation of autophagy gene activity. Our review identified 58 clinical studies that met the criteria. The number of publications supporting a beneficial clinical activity of VD in treating COVID-19 was 49 (86%), including 12 meta-analyses. Although the total patients included in all articles was 14,071,273, patients included in publications supporting a beneficial role of VD in COVID-19 were 14,029,411 (99.7%). Collectively, extensive observational studies indicated a decisive relationship between low VD levels and the severity of COVID-19 and mortality outcomes. Importantly, evidence from intervention studies has demonstrated the effectiveness of VD supplements in treating COVID-19. Furthermore, the results of 4 observational studies supported the beneficial role of VD in alleviating symptoms of long COVID-19 disease. However, eight RCTs and one meta-analysis of RCTs may contain low-grade evidence against a beneficial role of VD in COVID-19. Twenty-five articles have addressed the association between VDR and DBP genetic polymorphisms and treatment failure of VD in COVID-19. Impaired VDR signaling may underlie the variability of VD effects as non-genetic mechanisms. Interestingly, in recent studies, metformin has a beneficial therapeutic role in COVID-19 and long COVID-19, possibly by improving AMPK signaling of the VDR and enhancing the efficacy of the VD. In conclusion, evidence has been significantly strengthened over the past 18 months, with several meta-analyses and RCTs reporting conclusive beneficial effects of VD supplementation against COVID-19 and highlighting metformin to improve VDR sensitivity and efficacy in treating COVID-19 and long COVID-19.

Has a High Dose of Vitamin D3 Impacted Health Conditions in Older Adults?-A Systematic Review and Meta-Analysis Focusing on Dose 100,000 IU

BACKGROUND

Older adults are prone to vitamin D3 (VD3) deficiency, which may impair their health. A high dose of VD3 (HDVD3 = 100,000 IU) could improve their 25-hydroxyvitamin D3 [25(OH)D] level and health outcomes. However, evidence for such a beneficial effect of HDVD3 in older adults coming from clinical trials is mixed.

OBJECTIVE

To review the literature on the efficacy of a single dose of 100,000 IU of VD3 in older people.

METHODS

We searched PubMed/Medline, Science Direct, and NIH's clinical trials registry for clinical studies on the effect of a single high dose of VD3 on various health outcomes in older people. We also performed a meta-analysis using the standardized mean difference to assess the effect of VD3 on its blood level. Due to expected high heterogeneity, its amount (i.e., tau2) was estimated using the DerSimonian-Laird estimator. To estimate tau2, the Q-test for heterogeneity and the I2 statistic were calculated.

RESULTS

Search results identify 13 studies that reported diverse health outcomes, such as lung and cardiovascular function, skin cancer progression, intensive care unit mortality, immune system response, and bone density. The meta-analysis showed a significant increase in 25(OH)D blood levels after treatment in 10 studies, with an average standardized mean difference of 2.60 ng/mL (95% CI: 2.07 to 3.13). Their results suggested that a single high dose of VD3 may benefit intensive care unit patients and skin cancer patients in remission. However, evidence for other beneficial health effects of HDVD3 was mixed due to high heterogeneity among studies.

CONCLUSIONS

A single high dose of VD3 may positively affect some health outcomes in older people, possibly due to its pleiotropic and immunomodulatory effects. However, the evidence needs to be more extensive and consistent, and more rigorous studies are required to confirm the benefits and safety of VD3 high doses in older patients.

The role of vitamin D in the prevention and treatment of SARS-CoV-2 infection: A meta-analysis of randomized controlled trials

BACKGROUND

Vitamin D (VitD) has been shown to be important for the immune response of the respiratory system, but the preventive and therapeutic effects of vitamin D supplementation on SARS-CoV-2 infection are controversial. This study aimed to determine the role of vitamin D supplementation in the prevention and treatment of SARS-CoV-2 infection through a meta-analysis of randomized controlled trials.

METHODS

The databases of PubMed, Cochrane Library, Embase, Web of Science and Google Scholar were searched systematically from inception to April 17,2023 to identify trials involving a randomized comparison of vitamin D supplementation versus non-vitamin D supplementation for SARS-CoV-2 infection prevention or treatment.

RESULTS

We retrieved 25 eligible trials, including 8128 participants. Four trials compared the preventive effects of vitamin D supplementation on SARS-CoV-2 infection, and the results (RR 0.31; 95%CI 0.07 to 1.32) were inconclusive. Regarding the treatment of SARS-CoV-2 infection with vitamin D supplementation, it was found that vitamin D supplementation could significantly reduce the rates of ICU admission (RR 0.63; 95%CI 0.44 to 0.89) and mechanical ventilation (RR 0.58; 95%CI 0.39 to 0.84), but had no statistically significant effect on mortality. However, in subgroup analyses based on the patients' specific conditions, vitamin D supplementation significantly reduced the mortality in patients with vitamin D deficiency (RR 0.76; 95%CI 0.58 to 0.98).

CONCLUSION

Vitamin D supplementation may have some beneficial impact on the severity of illness caused by SARS-CoV-2, particularly in VitD deficient patients, but further studies are still needed.

The Effect of Vitamin D Supplementation on the Length of Hospitalisation, Intensive Care Unit Admission, and Mortality in COVID-19-A Systematic Review and Meta-Analysis

The coronavirus disease 2019 (COVID-19) pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has become a global health crisis and pushed researchers and physicians to discover possible treatments to improve the outcome of their patients. Vitamin D, known for its role in immune system function, has been hypothesized to play a role in COVID-19 treatment. A systematic review and meta-analysis were conducted to evaluate the efficacy of vitamin D supplementation in COVID-19, focusing on length of hospital stay (LOS), admission to the intensive care unit (ICU), and mortality. Thirteen randomized controlled trials (RCTs) were included, and the meta-analysis revealed that high-dose vitamin D supplementation showed potential benefits in reducing the length of hospital stay and ICU admission rates for patients with COVID-19. However, the overall effect on mortality did not reach statistical significance. While this systematic review suggests the potential benefits of high-dose vitamin D supplementation in reducing hospital stays and ICU admission in COVID-19 patients, caution is warranted due to the high heterogeneity and limitations of the included studies. Further large-scale randomized controlled trials with consistent study characteristics are needed to provide more robust evidence regarding the therapeutic benefits of vitamin D supplementation in COVID-19 outcomes.

COVID-19 and Other Pleiotropic Actions of Vitamin D: Proceedings from the Fifth International Conference "Vitamin D-Minimum, Maximum, Optimum" under the Auspices of the European Vitamin D Association (EVIDAS)

Vitamin D deficiency appeared as a worldwide pandemic markedly earlier than the COVID-19 pandemic was announced in global media [...].

Effect of Single High Dose Vitamin D Substitution in Hospitalized COVID-19 Patients with Vitamin D Deficiency on Length of Hospital Stay

Vitamin D and its role in the coronavirus-19 disease (COVID-19) pandemic has been controversially discussed, with inconclusive evidence about vitamin D3 (cholecalciferol) supplementation in COVID-19 patients. Vitamin D metabolites play an important role in the initiation of the immune response and can be an easily modifiable risk factor in 25-hydroxyvitamin D₃ (25(OH)D₃)-deficient patients. This is a multicenter, randomized, placebo-controlled double-blind trial to compare the effect of a single high dose of vitamin D₃ followed by treatment as usual (TAU) of daily vitamin D₃ daily until discharge versus placebo plus TAU in hospitalized patients with COVID-19 and 25(OH)D₃-deficiency on length hospital stay. We included 40 patients per group and did not observe a significant difference in the median length of hospital stay (6 days in both groups, p = 0.920). We adjusted the length of stay for COVID-19 risk factors (β = 0.44; 95% CI: -2.17-2.22), and center (β = 0.74; 95% CI: -1.25-2.73). The subgroup analysis in patients with severe 25(OH)D₃-deficiency (<25 nmol/L) showed a non-significant reduction in the median length of hospital stay in the intervention group (5.5 vs. 9 days, p = 0.299). The competing risk model with death did not reveal significant differences between the group in the length of stay (HR = 0.96, 95% CI 0.62-1.48, p = 0.850). Serum 25(OH)D₃ level increased significantly in the intervention group (mean change in nmol/L; intervention: +26.35 vs. control: -2.73, p < 0.001). The intervention with 140,000 IU vitamin D₃ + TAU did not significantly shorten the length of hospital stay but was effective and safe for the elevation of serum 25(OH)D₃ levels.

Hospital and laboratory outcomes of patients with COVID-19 who received vitamin D supplementation: a systematic review and meta-analysis of randomized controlled trials

Coronavirus disease 2019 (COVID-19) has a wide-ranging spectrum of clinical symptoms, from asymptomatic/mild to severe. Recent research indicates that, among several factors, a low vitamin D level is a modifiable risk factor for COVID-19 patients. This study aims to evaluate the effect of vitamin D on hospital and laboratory outcomes of patients with COVID-19.Five databases (PubMed, Embase, Scopus, Web of Science, and Cochrane Library) and clinicaltrials.gov were searched until July 2022, using relevant keywords/Mesh terms. Only randomized clinical trials (RCTs) that addressed the topic were included. The Cochrane tool was used to assess the studies' risk of bias, and the data were analyzed using the review manager (RevMan 5.4).We included nine RCTs with 1586 confirmed COVID-19 patients. Vitamin D group showed a significant reduction of intensive care unit (ICU) admission (risk ratio = 0.59, 95% confidence interval (CI) [0.41, 0.84], P = 0.003), and higher change in vitamin D level (standardized mean difference = 2.27, 95% CI [2.08, 2.47], P < 0.00001) compared to the control group. Other studied hospital and laboratory outcomes showed non-significant difference between vitamin D and the control group (P ≥ 0.05).In conclusion, vitamin D reduced the risk of ICU admission and showed superiority in changing vitamin D level compared to the control group. However, other outcomes showed no difference between the two groups. More RCTs are needed to confirm these results.

Potential Benefit of Vitamin D Supplementation in COVID-19

Vitamin D is an important nutrient in the body that plays a vital role in immune system function. Several epidemiologic studies have shown that low vitamin D levels are found in a large percentage of COVID-19 patients with acute respiratory failure and that vitamin D levels may predict mortality in COVID-19 infection. Based on these findings, vitamin D supplementation may be an effective approach to preventing and/or treating COVID-19. Potential underlying mechanisms and clinical trial data evaluating the impact of supplementation in humans are described below.

Consensus and Controversial Aspects of Vitamin D and COVID-19

OBJECTIVES

This work aims to review and discuss controversial topics in the field of vitamin D, SARS-CoV-2 infection, and COVID-19.

PARTICIPANTS

The International Conferences "Controversies in Vitamin D" are a series of workshops that started in 2017 featuring international experts and leaders in vitamin D research and clinical practice. The 5th annual conference was held in Stresa, Italy, from 15 to 18 September 2021.

EVIDENCE

Before the event, participants reviewed available studies on their assigned topic, drafted a related abstract, and presented their findings at the time of the conference. Relevant literature that became available since was also discussed within the panel and updated accordingly.

CONSENSUS

Before the event, the drafted abstracts had been merged to prepare a preliminary document. After the conference presentations, in-depth discussions in open sessions led to consensus. The document was subsequently modified according to discussions and up-to-date literature inclusion.

CONCLUSIONS

There is quite consistent evidence for an association between low 25 OH vitamin D (25(OH)D) levels and poor COVID-19 outcomes, despite heterogeneous publications of variable quality. However, the low vitamin D status in COVID-19 patients might also reflect reverse causality. Vitamin D supplementation might have a positive role in COVID-19 prevention. The evidence supporting a beneficial effect of vitamin D treatment in decreasing the risk of COVID-19 complications is conflicting. Conclusive statement regarding the beneficial effect of vitamin D in this context await high-quality randomized controlled trials.

Vitamin D and COVID-19: Narrative Review after 3 Years of Pandemic

Active vitamin D [1,25(OH)₂D₃-calcitriol] is a secosteroid hormone whose receptor is expressed on all cells of the immune system. Vitamin D has a global anti-inflammatory effect and its role in the management of a SARS-CoV-2 infection has been investigated since the beginning of the COVID-19 pandemic. In this narrative review, the laboratory and clinical results of a vitamin D supplementation have been collected from both open-label and blinded randomized clinical trials. The results are generally in favor of the utility of maintaining the serum concentrations of calcifediol [25(OH)D₃] at around 40 ng/mL and of the absolute usefulness of its supplementation in subjects with deficient serum levels. However, two very recent large-scale studies (one open-label, one placebo-controlled) have called into question the contribution of vitamin D to clinical practice in the era of COVID-19 vaccinations. The precise role of a vitamin D supplementation in the anti-COVID-19 armamentarium requires further investigations in light of the breakthrough which has been achieved with mass vaccinations.

Nutraceuticals for Complementary Treatment of Multisystem Inflammatory Syndrome in Children: A Perspective from Their Use in COVID-19

Multisystem inflammatory syndrome in children (MIS-C) has been widely reported in some children diagnosed with SARS-CoV-2. Clinical signs of MIS-C are manifested at 2 to 4 weeks after SARS-CoV-2 infection, where elevated biomarkers of inflammation and cardiac dysfunction are the hallmark of this syndrome when infection or exposure to SARS-CoV-2 has been confirmed. However, after two years of acknowledgment, MIS-C treatment is still under research to reach safety and effectiveness in the acute phase in children. Therefore, in this review, we discuss the potential use of natural compounds with antioxidant and anti-inflammatory effects to reduce collateral damage caused by hyperinflammation in MIS-C pathology for new research in treatment and interventions.

Visual analysis of the research trend and status on the association between vitamin D and immunity: From 2012 to 2021

Objective

We conducted this study to visualize hot spots and trends in the correlation between vitamin D and immunity over the past decade with bibliometric analysis.

Methods

We collected relevant articles in the Web of Science Core Collection from 2012 to 2021 as the data source, and then used CiteSpace software to perform the data analysis. Some graphics were done with Graphpad software.

Results

A total of 1,656 articles were retrieved, with an average citation count of 25.2 times. The United States (439 articles, 26.51%) has the top number of published articles, followed by China (164 articles, 9.90%), England (135 articles, 8.15%), Italy (114 articles, 6.88%), and India (82 articles, 4.95%). The most literature is found in areas of Immunology (337 articles, 20.35%) and Biochemistry Molecular Biology (179 articles, 10.81%). In terms of institutions, the top five institutions with the highest number of publications all belong to Europe. Among them, the League of European Research Universities (LERU) (121, 7.31%) has a greater proportion of output articles. The United States Department of Health Human Services (225, 13.59%) and National Institutes of Health United States (223, 13.47%) funded most articles. The leading five authors with the largest number of publications were Hewison M (19, 1.15%), Bergman P (14, 0.85%), Agerberth B (13, 0.76%), Carlberg C (12, 0.73%), and White JH (12, 0.73%). The top five keywords with the highest co-occurrence frequency are “vitamin d” (367), “d deficiency” (217), “expression” (195), “association” (151), and “d receptor” (132). Among the 17 keyword clusters, the largest cluster is #0 “diet.” Despite cluster #13 “covid-19,” most of the clusters were conducted the studies before 2012.

Conclusion

The overall development of research in this field is promising. Western developed countries made outstanding contributions in this area and still take the leading role. But the participation of developing and low-income countries is also impressive. The potential therapeutic effects of vitamin D in immune-related diseases have been noted, especially in multiple sclerosis, COVID-19, etc. This is also the focus and frontier of current research. However, there is still no consensus conclusion in this field. Further research is needed in the future.