Vitamin D deficiency aggravates COVID-19: systematic review and meta-analysis

Are Nutraceuticals Effective in COVID-19 and Post-COVID Prevention and Treatment?

The beginning of the end or the end of the beginning? After two years mastered by coronavirus disease 19 (COVID-19) pandemic, we are now witnessing a turnaround. The reduction of severe cases and deaths from COVID-19 led to increasing importance of a new disease called post-COVID syndrome. The term post-COVID is used to indicate permanency of symptoms in patients who have recovered from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Immune, antiviral, antimicrobial therapies, as well as ozone therapy have been used to treat COVID-19 disease. Vaccines have then become available and administered worldwide to prevent the insurgence of the disease. However, the pandemic is not over yet at all given the emergence of new omicron variants. New therapeutic strategies are urgently needed. In this view, great interest was found in nutraceutical products, including vitamins (C, D, and E), minerals (zinc), melatonin, probiotics, flavonoids (quercetin), and curcumin. This review summarizes the role of nutraceuticals in the prevention and/or treatment of COVID-19 disease and post-COVID syndrome.

IFI44 is an immune evasion biomarker for SARS-CoV-2 and Staphylococcus aureus infection in patients with RA

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a global pandemic of severe coronavirus disease 2019 (COVID-19). Staphylococcus aureus is one of the most common pathogenic bacteria in humans, rheumatoid arthritis (RA) is among the most prevalent autoimmune conditions. RA is a significant risk factor for SARS-CoV-2 and S. aureus infections, although the mechanism of RA and SARS-CoV-2 infection in conjunction with S. aureus infection has not been elucidated. The purpose of this study is to investigate the biomarkers and disease targets between RA and SARS-CoV-2 and S. aureus infections using bioinformatics analysis, to search for the molecular mechanisms of SARS-CoV-2 and S. aureus immune escape and potential drug targets in the RA population, and to provide new directions for further analysis and targeted development of clinical treatments.

Methods

The RA dataset (GSE93272) and the S. aureus bacteremia (SAB) dataset (GSE33341) were used to obtain differentially expressed gene sets, respectively, and the common differentially expressed genes (DEGs) were determined through the intersection. Functional enrichment analysis utilizing GO, KEGG, and ClueGO methods. The PPI network was created utilizing the STRING database, and the top 10 hub genes were identified and further examined for functional enrichment using Metascape and GeneMANIA. The top 10 hub genes were intersected with the SARS-CoV-2 gene pool to identify five hub genes shared by RA, COVID-19, and SAB, and functional enrichment analysis was conducted using Metascape and GeneMANIA. Using the NetworkAnalyst platform, TF-hub gene and miRNA-hub gene networks were built for these five hub genes. The hub gene was verified utilizing GSE17755, GSE55235, and GSE13670, and its effectiveness was assessed utilizing ROC curves. CIBERSORT was applied to examine immune cell infiltration and the link between the hub gene and immune cells.

Results

A total of 199 DEGs were extracted from the GSE93272 and GSE33341 datasets. KEGG analysis of enrichment pathways were NLR signaling pathway, cell membrane DNA sensing pathway, oxidative phosphorylation, and viral infection. Positive/negative regulation of the immune system, regulation of the interferon-I (IFN-I; IFN-α/β) pathway, and associated pathways of the immunological response to viruses were enriched in GO and ClueGO analyses. PPI network and Cytoscape platform identified the top 10 hub genes: RSAD2, IFIT3, GBP1, RTP4, IFI44, OAS1, IFI44L, ISG15, HERC5, and IFIT5. The pathways are mainly enriched in response to viral and bacterial infection, IFN signaling, and 1,25-dihydroxy vitamin D3. IFI44, OAS1, IFI44L, ISG15, and HERC5 are the five hub genes shared by RA, COVID-19, and SAB. The pathways are primarily enriched for response to viral and bacterial infections. The TF-hub gene network and miRNA-hub gene network identified YY1 as a key TF and hsa-mir-1-3p and hsa-mir-146a-5p as two important miRNAs related to IFI44. IFI44 was identified as a hub gene by validating GSE17755, GSE55235, and GSE13670. Immune cell infiltration analysis showed a strong positive correlation between activated dendritic cells and IFI44 expression.

Conclusions

IFI144 was discovered as a shared biomarker and disease target for RA, COVID-19, and SAB by this study. IFI44 negatively regulates the IFN signaling pathway to promote viral replication and bacterial proliferation and is an important molecular target for SARS-CoV-2 and S. aureus immune escape in RA. Dendritic cells play an important role in this process. 1,25-Dihydroxy vitamin D3 may be an important therapeutic agent in treating RA with SARS-CoV-2 and S. aureus infections.

The Perspective of Vitamin D on suPAR-Related AKI in COVID-19

The coronavirus disease 2019 (COVID-19) pandemic has claimed the lives of millions of people around the world. Severe vitamin D deficiency can increase the risk of death in people with COVID-19. There is growing evidence that acute kidney injury (AKI) is common in COVID-19 patients and is associated with poorer clinical outcomes. The kidney effects of SARS-CoV-2 are directly mediated by angiotensin 2-converting enzyme (ACE2) receptors. AKI is also caused by indirect causes such as the hypercoagulable state and microvascular thrombosis. The increased release of soluble urokinase-type plasminogen activator receptor (suPAR) from immature myeloid cells reduces plasminogen activation by the competitive inhibition of urokinase-type plasminogen activator, which results in low plasmin levels and a fibrinolytic state in COVID-19. Frequent hypercoagulability in critically ill patients with COVID-19 may exacerbate the severity of thrombosis. Versican expression in proximal tubular cells leads to the proliferation of interstitial fibroblasts through the C3a and suPAR pathways. Vitamin D attenuates the local expression of podocyte uPAR and decreases elevated circulating suPAR levels caused by systemic inflammation. This decrease preserves the function and structure of the glomerular barrier, thereby maintaining renal function. The attenuated hyperinflammatory state reduces complement activation, resulting in lower serum C3a levels. Vitamin D can also protect against COVID-19 by modulating innate and adaptive immunity, increasing ACE2 expression, and inhibiting the renin-angiotensin-aldosterone system. We hypothesized that by reducing suPAR levels, appropriate vitamin D supplementation could prevent the progression and reduce the severity of AKI in COVID-19 patients, although the data available require further elucidation.

Management and treatment of long COVID symptoms in general practices: An online-based survey

Independent from initial severity, many patients develop persistent symptoms after infection with SARS-CoV-2, described as long COVID syndrome. Most of these patients are treated by general practitioners (GPs). As evidence-based treatment recommendations are still sparse, GPs must make their therapy decisions under uncertainty. We investigated (1) the most frequently observed long COVID symptoms in general practices and (2) GPs' applied treatment and rehabilitation plans for these symptoms. In total, 143 German GPs participated in an online-based survey between 05/2021 and 07/2021. We found that each GP practice was treating on average 12 patients with long COVID symptoms. Most frequently seen symptoms were fatigue and reduced performance. Current therapy options were rated as poor and loss of smell and taste, fatigue, or lack of concentration were perceived to be especially difficult to treat. The use of drug and non-drug therapies and specialist referrals focused primarily on physiological and less on psychosomatic/psychological rehabilitation and followed guidelines of similar conditions. Our results provide first insights into how GPs approach a newly emerging condition in the absence of guidelines, evidence-based recommendations, or approved therapies, and might inform about GP preparedness in future pandemics. Our results also emphasize a gap between the current knowledge of the long COVID manifestation and knowledge about effective rehabilitation.

Vitamin D as a Possible COVID-19 Prevention Strategy

Vitamin D is no longer considered an agent only affecting calcium phosphate metabolism. A number of studies over the past few years have demonstrated its role in immunomodulation and its influence on the development and functioning of the brain and nervous system. In the current epidemiological crisis caused by coronavirus disease 2019 (COVID-19), the immunoprotective role of vitamin D has been discussed by some authors regarding whether it contributes to protection against this serious disease or whether its use does not play a role. Non-standard approaches taken by laboratories in examining the serum levels of the vitamin D metabolite calcidiol have contributed to inconsistent results. We examined the serum of 60 volunteers in the spring and autumn of 2021 who declared whether they were taking vitamin D at the time of sampling. Furthermore, the tested participants noted whether they had experienced COVID-19. A newly developed liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used to measure calcidiol levels. The analysis of variance (ANOVA) model of Statgraphics Centurion 18 statistical software from Statgraphics Technologies was used for calculations. The results of this study showed that those who took vitamin D suffered significantly less often from COVID-19 than those who did not take vitamin D.

Obesity, Hypovitaminosis D, and COVID-19: the Bermuda Triangle in Public Health

PURPOSE OF REVIEW

The COVID-19 pandemic has challenged public health to a significant extent by markedly increasing morbidity and mortality. Evidence suggests that obesity and hypovitaminosis D constitute important risk factors for SARS-CoV-2 infection, severity of disease, and poor outcomes. Due to their high prevalence globally, obesity and hypovitaminosis D are considered pandemics. This review presents current epidemiologic and genetic data linking obesity, hypovitaminosis D, and COVID-19, highlighting the importance of the convergence of three pandemics and their impact on public health. We also briefly summarize potential mechanisms that could explain these links.

RECENT FINDINGS

Epidemiologic data have shown that obesity is an independent risk factor for COVID-19, severe disease and death, and genetic evidence has suggested a causal association between obesity-related traits and COVID-19 susceptibility and severity. Additionally, obesity is independently associated with hypovitaminosis D, which is highly prevalent in subjects with obesity. Hypovitaminosis D is independently associated with a higher risk for COVID-19, severity, hospitalization, infectious complications, acute respiratory distress syndrome, and poor outcomes. However, genome-wide association studies have not revealed any causal association between vitamin D levels and the risk for COVID-19, while there is no robust evidence for a beneficial role of vitamin D supplementation in the prevention and treatment of COVID-19. In the context of the ongoing COVID-19 pandemic, the epidemiologic impact of obesity and hypovitaminosis D is emphasized. Efforts to increase public awareness and reinforce preventive and therapeutic measures against obesity and hypovitaminosis D are strongly required.

The Role of Diet in Regulation of Macrophages Functioning

The great importance of diet for health and high life-expectancy is established. The impact of nutrients on immune system is a point of growing research interest. Recent studies have found pro- and anti-inflammatory properties of some diet patterns and nutrients that can be used from the bench to the bedside for chronic low-grade inflammatory status correction. In this regard, the assessment of potential effects of nutrition on macrophage differentiation, proliferation, and functioning in health and disease is highly demanded. In this review, we present current data on the effects of nutrients on the macrophage functioning.

Rapidly Increasing Serum 25(OH)D Boosts the Immune System, against Infections-Sepsis and COVID-19

Vitamin D deficiency is a global public health problem, a pandemic that commonly affects the elderly and those with comorbidities such as obesity, diabetes, hypertension, respiratory disorders, recurrent infections, immune deficiency, and malignancies, as well as ethnic minorities living in temperate countries. The same groups were worst affected by COVID-19. Since vitamin D deficiency weakens the immune system, it increases the risk of infections, complications, and deaths, such as from sepsis and COVID-19. Deficiency can be remedied cost-effectively through targeted food fortification, supplementation, and/or daily safe sun exposure. Its endocrine functions are limited to mineral metabolism, musculoskeletal systems, specific cell membrane interactions, and parathyroid gland functions. Except for the rapid, endocrine, and cell membrane-based non-genomic functions, all other biological and physiological activities of vitamin D depend on the adequate intracellular synthesis of 1,25(OH)2D (calcitriol) in peripheral target cells via the genome. Calcitriol mediates autocrine (intracrine) and paracrine signalling in immune cells, which provides broader, protective immune functions crucial to overcoming infections. The synthesis of 1,25(OH)2D (calcitriol) in peripheral target cells is dependent on diffusion and endocytosis of D3 and 25(OH)D from the circulation into them, which requires maintenance of serum 25(OH)D concentration above 50 ng/mL. Therefore, in acute infections such as sepsis and respiratory infections like COVID-19, it is necessary to rapidly provide its precursors, D3 and 25(OH)D, through the circulation to generate adequate intracellular calcitriol. Immune defence is one of the crucial non-hormonal functions of vitamin D. A single oral (bolus) dose or divided upfront loading doses between 100,000 and 500,000 IU, using 50,000 IU vitamin D3 increase the serum 25(OH)D concentrations to a therapeutic level of above 50 ng/mL that lasts between two to three months. This takes three to five days to raise serum 25(OH)D. In contrast, a single oral dose of calcifediol (0.014 mg/kg body weight) can generate the needed 25(OH)D concentration within four hours. Considering both D3 and 25(OH)D enter immune cells for generating calcitriol, using the combination of D3 (medium-term) and calcifediol (immediate) is cost-effective and leads to the best clinical outcome. To maximise protection against infections, particularly to reduce COVID-19-associated complications and deaths, healthcare workers should advise patients on safe sun exposure, adequate vitamin D supplementation and balanced diets containing zinc, magnesium, and other micronutrients to support the immune system. Meanwhile, governments, the World Health Organisation, the Centers for Disease Control, and governments should consider similar recommendations to physicians and the public, change the outdated vitamin D and other micronutrient recommendations directed to their population, and organise targetted food fortification programs for the vulnerable groups. This article discusses a rational approach to maintaining a sustained serum 25(OH)D concentration above 50 ng/mL, necessary to attain a robust immune system for overcoming infections. Such would cost-effectively improve the population’s health and reduce healthcare costs. It also describes three cost-effective, straightforward protocols for achieving and sustaining therapeutic serum 25(OH)D concentrations above 50 ng/mL (>125 nmol/L) to keep the population healthy, reduce absenteeism, improve productivity, and lower healthcare costs.

Vitamin D deficiency is Associated with Increased Risk of Delirium and Mortality among Critically Ill, Elderly Covid-19 Patients

Background and aim

Data on the associations of vitamin D levels with severe outcomes of coronavirus disease 2019 (COVID-19) among critically ill elderly patients are not conclusive and also no information is available about some outcomes such as delirium. Therefore, the current study was done to assess these associations in critically ill elderly COVID-19 patients.

Methods

In total, 310 critically ill COVID-19 patients, aged ≥ 65 years, were included in the current single center prospective study. All patients were hospitalized in the intensive care unit (ICU). We collected data on demographic characteristics, laboratory parameters, blood pressure, comorbidities, medications, and types of mechanical ventilation at baseline (the first day of ICU admission). Patients were categorized based on serum 25(OH)D3 levels at the baseline [normal levels (>30 ng/mL), insufficiency (20–30 ng/mL), deficiency (<20 ng/mL)]. Data on delirium incidence, mortality, invasive mechanical ventilation (IMV) requirement during treatment, length of ICU and hospital admission, and re-hospitalization were recorded until 45 days after the baseline.

Results

Vitamin D deficiency and insufficiency were prevalent among 12 % and 37 % of study participants, respectively. In terms of baseline differences, patients with vitamin D deficiency were more likely to be older, have organ failure, take propofol, need IMV, and were less likely to need face mask compared to patients with normal levels of vitamin D. A significant positive association was found between vitamin D deficiency and risk of delirium. After controlling for potential confounders, patients with vitamin D deficiency had a 54 % higher risk of delirium compared to those with vitamin D sufficiency (HR: 1.54, 95 % CI: 1.02–2.33). Such a positive association was also seen for 45-day COVID-19 mortality (HR: 3.95, 95 % CI: 1.80–8.67). Also, each 10 ng/mL increase in vitamin D levels was associated with a 45 % and 26 % lower risk of 45-day mortality (HR: 0.55, 95 % CI: 0.40–0.74) and ICU mortality due to COVID-19 (HR: 0.74, 95 % CI: 0.60–0.92), respectively. In terms of other COVID-19 outcomes including IMV requirement during treatment, prolonged hospitalization, and re-hospitalization, we found no significant association in relation to serum 25(OH)D3 levels either in crude or fully adjusted models.

Conclusion

Vitamin D deficiency was associated with an increased risk of delirium and mortality among critically ill elderly COVID-19 patients.

A web-based survey assessing perceived changes in diet, physical activity and sleeping behaviours in adults with type 1 and type 2 diabetes during the COVID-19 pandemic in the UK

Background

The COVID-19 pandemic may have contributed to poorer self-management (ie, diet, physical activity and sleep) of diabetes mellitus (DM), which might predispose individuals to more severe COVID-19 outcomes.

Objective

The first objective was to capture perceived changes in diet, physical activity and sleeping during the COVID-19 pandemic in adults with type 1 (T1DM) and type 2 diabetes mellitus (T2DM) in the UK. A second objective was to explore differences between individuals with DM compared with 'no' or 'other' health conditions.

Methods

Participants aged >18 years were selected by convenience. Individuals subscribed to the Diabetes.co.uk community were sent a web-based survey including questions about demographics and health, followed by 5-point Likert-type scale questions relating to lifestyle-related behaviours during the COVID-19 pandemic. Individuals were grouped by diagnosis of DM, 'other' or 'no' health condition and responses were compared.

Results

4764 individuals responded, with 2434 (51.3%) being female and 1550 (32.6%) aged 55-64 years. T2DM (2974; 62.7%), hypertension (2147; 45.2%) and T1DM (1299; 27.4%) were most frequently reported. Compared with T1DM, 'no' or 'other' health conditions, respondents with T2DM reported making a less conscious effort to get outside and exercise daily (p<0.001) and spending no time outdoors (p=0.001). Weight loss was more frequently reported in respondents with T2DM (p=0.005). More individuals with T2DM reported consuming convenience foods (p=0.012) and sugary foods (p=0.021), yet eating more fresh foods (p=0.001) and drinking less alcohol than normal (p<0.001). More individuals with T1DM and T2DM reported worse sleep quality (p=0.004).

Conclusions

Our study highlighted important differences in lifestyle by individuals with T1DM, T2DM, other and no health conditions in relation to the COVID-19 pandemic. Establishing surveillance systems and conducting repeated assessments are required to analyse how the situation shifted over time and whether adverse collateral effects of the pandemic were sustained in those with chronic health conditions.

Vitamin D and SARS-CoV2 infection, severity and mortality: A systematic review and meta-analysis

To assess the evidence on SARS-CoV2 infection and Covid-19 in relation to deficiency and supplementation of vitamin D, we conducted a systematic review up to April 2021. We summarised data from 38 eligible studies, which presented risk estimates for at least one endpoint, including two RCT and 27 cohort-studies: 205565 patients with information on 25OHD status and 2022 taking vitamin D supplementation with a total of 1197 admitted to the ICU or who needed invasive mechanical ventilation or intubation and hospital stay, and more than 910 Covid-19 deaths. Primary outcomes were severity and mortality and the main aim was to evaluate the association with vitamin D supplementation. Random effects models showed that supplementation was associated with a significant lower risk of both Covid-19 severe disease (SRR 0.38, 95% CI 0.20-0.72, 6 studies) and mortality (SRR 0.35, 95% CI 0.17-0.70, 8 studies). There were no statistically significant dose differences between studies: summary estimates with regular doses remain statistically significant, suggesting that higher doses are not necessary. For patients on vitamin D supplementation, a greater reduction in mortality risk emerged in older individuals and at higher latitudes. Regarding the quality of studies, assessed using the New Castle-Ottawa quality scale, the analysis revealed in most cases no statistically significant differences between low, medium or high quality studies. We found significant associations of vitamin D supplementation with Covid-19, encompassing risks of disease worsening and mortality, especially in seasons characterized by 25OHD deficiency and with not severe patients. Dedicated randomized clinical studies are encouraged to confirm these results.

Vitamin D deficiency in athletes: Laboratory, clinical and field integration

Vitamin D deficiency is highly prevalent in athletes. Increased utilisation and storage depletion may be key contributing factor. We found a higher prevalence of vitamin D inadequacy (deficiency/ insufficiency) in power than endurance sport athletes, which may be related to vitamin D utilisation and reserve in skeletal muscles.

The Impact of the Highly Virulent SARS-CoV-2 Gamma Variant on Young Adults in the State of São Paulo: Was It Inevitable?

Background

The coronavirus disease 2019 (COVID-19) pandemic had and is still having a tremendous impact on people all over the world, but it has been particularly harsh in South America. Nine out of 13 South American countries are among the 50 countries with the highest COVID-19 death rates. The gamma severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant that emerged by the end of 2020 in the Brazilian Amazon quickly spread throughout the country causing the harsh COVID-19 second wave. This variant displayed high viral loads, high transmissibility, and increased virulence as compared to previous variants.

Aims

The aim of this retrospective study is to revisit and analyse the epidemiology of the COVID-19 second wave in the state of São Paulo, the most populous Brazilian state. In addition to examining the possible factors that led to the emergence and propagation of the gamma variant, measures that could have prevented its spread and that of other highly virulent variants were also investigated.

Materials and methods

Data from São Paulo's official sources on morbidity, mortality, age distribution, and testing prior to and during the COVID-19 second wave (February - June 2021) and data regarding the distribution of SARS-CoV-2 variants in the country were parsed, analyzed, and compared to the period that anteceded the eruption of the second COVID-19 wave.

Results

In the state of São Paulo, the toll of the COVID-19 second wave surpassed that of the first 11 months of the pandemic (from March 2020 to January 2021), as 56% of the deaths occurred in the five months of the second wave between February and June 2021. The mean age of COVID-19 victims, which was already below life expectancy in the state dropped even further in the pandemic's second wave, reaching an average of 60 years of age. The years of life lost per death per month doubled and the case-fatality rate (CFR) of young adults (20-39 years old) more than trebled during this period. A number of hypotheses have been raised that might explain the emergence and spread of the gamma variant and the measures that could have been taken to prevent it and minimise its impact on the population.

Conclusions

Over 142,000 people died as a result of the SARS-CoV-2 gamma variant sweep in São Paulo in the first semester of 2021. Due to its high viral load, the gamma variant displayed high transmissibility and a high degree of virulence resulting in increased case fatality rates across most age tiers. Notably, this second wave was marked by a very significant increase in deaths among young adults. This increase was at least partially due to a deterioration in general health provoked by non-pharmaceutical interventions. In hindsight, a safer and more effective measure might have been to allow the free spread of the virus among the young and healthy in the first wave, thus conferring immunity against more virulent variants that emerged later on.

Vitamin D Deficiency and Comorbidities as Risk Factors of COVID-19 Infection: A Systematic Review and Meta-analysis

OBJECTIVES

Extensive evidence links low vitamin D status and comorbidities with coronavirus disease 2019 (COVID-19) outcomes, but the results of published studies are contradictory. Therefore, we investigated the association of lower levels of vitamin D and comorbidities with the risk of COVID-19 infection.

METHODS

We searched MEDLINE (via PubMed), Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov for articles published until August 20, 2021. Sixteen eligible studies were identified (386 631 patients, of whom 181 114 were male). We included observational cohort and case-control studies that evaluated serum levels of vitamin D in COVID-19-positive and COVID-19-negative patients. Mean differences (MDs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Significantly lower vitamin D levels were found in COVID-19-positive patients (MD, -1.70; 95% CI, -2.74 to -0.66; p=0.001), but with variation by study design (case-control: -4.04; 95% CI, -5.98 to -2.10; p<0.001; cohort: -0.39; 95% CI, -1.62 to 0.84; p=0.538). This relationship was more prominent in female patients (MD, -2.18; 95% CI, -4.08 to -0.28; p=0.024) than in male patients (MD, -1.74; 95% CI, -3.79 to 0.31; p=0.096). Male patients showed higher odds of having low vitamin D levels (odds ratio [OR], 2.09; 95% CI, 1.38 to 3.17; p<0.001) than female patients (OR, 1.17; 95% CI, 0.74 to 1.86; p=0.477). Comorbidities showed inconsistent, but generally non-significant, associations with COVID-19 infection.

CONCLUSIONS

Low serum vitamin-D levels were significantly associated with the risk of COVID-19 infection. This relationship was stronger in female than in male COVID-19 patients. Limited evidence was found for the relationships between comorbidities and COVID-19 infection, warranting large population-based studies to clarify these associations.

Vitamin D prescribing practices among clinical practitioners during the COVID-19 pandemic

Background and Aims

COVID-19 has caused devastation globally. Low vitamin D status, particularly during the winter months, remains commonplace around the world, and it is thought to be one of the contributing factors toward causation and severity of COVID-19. Many guidelines do not recommend vitamin D for the treatment or prevention of the disease. Hence, we set out to conduct a global survey to understand the use and prescribing habits of vitamin D among clinicians for COVID-19.

Methods

An online anonymous questionnaire was sent to clinicians enquiring about their prescribing habits of vitamin D and personal use of vitamin D. Data of the survey were collected between January 15, 2021, and February 13, 2021.

Results

Four thousand four hundred forty practicing clinicians were included in the analysis, with the majority of those responding from Asia, followed by Europe. 82.9% prescribed vitamin D before COVID-19, more commonly among general practitioners (GPs) in comparison with medical specialists, and Asian clinicians were more likely to prescribe vitamin D in comparison with Caucasian physicians (p < 0.01). GPs were also more likely to prescribe vitamin D prophylactically to prevent COVID-19 in comparison with medical specialists (OR 1.47, p < 0.01). Most GPs (72.8%) would also prescribe vitamin D to treat COVID-19 in comparison with medical specialists (OR 1.81, p < 0.01), as well as more Asian in comparison with Caucasian physicians (OR 4.57, p < 0.01). 80.4% of respondents were taking vitamin D, more so in the 45-54 and 65-74 age groups in comparison with the 18-24 years category (OR 2.15 and 2.40, respectively, both p < 0.05), many of whom did so before COVID-19 (72.1%).

Conclusion

This survey has shown that many clinicians would prescribe vitamin D for the prevention and treatment of COVID-19. The majority would also recommend measuring vitamin D levels, but not so in patients with COVID-19.

Vitamin D Endocrine System and COVID-19: Treatment with Calcifediol

The COVID-19 pandemic is the greatest challenge facing modern medicine and public health systems. The viral evolution of SARS-CoV-2, with the emergence of new variants with in-creased infectious potential, is a cause for concern. In addition, vaccination coverage remains in-sufficient worldwide. Therefore, there is a need to develop new therapeutic options, and/or to optimize the repositioning of drugs approved for other indications for COVID-19. This may include the use of calcifediol, the prohormone of the vitamin D endocrine system (VDES) as it may have potential useful effects for the treatment of COVID-19. We review the aspects associating COVID-19 with VDES and the potential use of calcifediol in COVID-19. VDES/VDR stimulation may enhance innate antiviral effector mechanisms, facilitating the induction of antimicrobial peptides/autophagy, with a critical modulatory role in the subsequent host reactive hyperinflammatory phase during COVID-19: By decreasing the cytokine/chemokine storm, regulating the renin–angiotensin–bradykinin system (RAAS), modulating neutrophil activity and maintaining the integrity of the pulmonary epithelial barrier, stimulating epithelial repair, and directly and indirectly decreasing the increased coagulability and prothrombotic tendency associated with severe COVID-19 and its complications. Available evidence suggests that VDES/VDR stimulation, while maintaining optimal serum 25OHD status, in patients with SARS-CoV-2 infection may significantly reduce the risk of acute respiratory distress syndrome (ARDS) and severe COVID-19, with possible beneficial effects on the need for mechanical ventilation and/or intensive care unit (ICU) admission, as well as deaths in the course of the disease. The pharmacokinetic and functional characteristics of calcifediol give it superiority in rapidly optimizing 25OHD levels in COVID-19. A pilot study and several observational intervention studies using high doses of calcifediol (0.532 mg on day 1 and 0.266 mg on days 3, 7, 14, 21, and 28) dramatically decreased the need for ICU admission and the mortality rate. We, therefore, propose to use calcifediol at the doses described for the rapid correction of 25OHD deficiency in all patients in the early stages of COVID-19, in association, if necessary, with the new oral antiviral agents.

Hallmarks of Severe COVID-19 Pathogenesis: A Pas de Deux Between Viral and Host Factors

Two years into Coronavirus Disease 2019 (COVID-19) pandemic, a comprehensive characterization of the pathogenesis of severe and critical forms of COVID-19 is still missing. While a deep dysregulation of both the magnitude and functionality of innate and adaptive immune responses have been described in severe COVID-19, the mechanisms underlying such dysregulations are still a matter of scientific debate, in turn hampering the identification of new therapies and of subgroups of patients that would most benefit from individual clinical interventions. Here we review the current understanding of viral and host factors that contribute to immune dysregulation associated with COVID-19 severity in the attempt to unfold and broaden the comprehension of COVID-19 pathogenesis and to define correlates of protection to further inform strategies of targeted therapeutic interventions.

The Association Between Vitamin D Serum Level and COVID-19 Patients’ Outcomes in a Tertiary Center in Saudi Arabia: A Retrospective Cohort Study

Vitamin D deficiency has been associated with the risk for immune-mediated inflammatory reactions in various respiratory infections. Our study investigated the association between vitamin D deficiency and coronavirus disease 2019 (COVID-19) patients’ outcomes. We included 545 patients who were admitted to a tertiary center in Jeddah, Saudi Arabia from March 2020 to July 2021 with a vitamin D serum test result at the time of infection or prior to disease onset. The data were extracted retrospectively using a data collection sheet. Our primary outcomes were intensive care unit (ICU) admission and in-hospital mortality. The cut-off values for vitamin D were <25, 25-49, and 50-250 for deficient, suboptimal, and optimal levels respectively. Our result revealed that there is no association between vitamin D serum levels deficiency and ICU admission (OR=1.08, p=0.75) or in-hospital mortality (OR=1.74, p=0.97). ICU admission and in-hospital mortality percentages in patients with vitamin D deficiency were 14.1% and 6.4%, respectively. In comparison, percentages for patients with optimal levels were 16.67% and 6.15% for ICU admission and in-hospital mortality, respectively. Smoking was not associated with ICU admission (p=0.05) or in-hospital mortality (p=0.38). Our study does not support a relationship between vitamin D deficiency and COVID-19 patients’ outcomes. Future studies should be directed toward conducting randomized clinical trials to determine whether vitamin D has an effective role in reducing COVID-19 severity.

Vitamin D for Recovery of COVID-19 in Patients With Chronic Kidney Disease

The severity of coronavirus disease 2019 (COVID-19) is determined not only by viral damage to cells but also by the immune reaction in the host. In addition to therapeutic interventions that target the viral infection, immunoregulation may be helpful in the management of COVID-19. Vitamin D exerts effects on both innate and adaptive immunity and subsequently modulates immune responses to bacteria and viruses. Patients with chronic kidney disease (CKD) frequently have vitamin D deficiency and increased susceptibility to infection, suggesting a potential role of vitamin D in this vulnerable population. In this paper, we review the alterations of the immune system, the risk of COVID-19 infections and mechanisms of vitamin D action in the pathogenesis of COVID-19 in CKD patients. Previous studies have shown that vitamin D deficiency can affect the outcomes of COVID-19. Supplementing vitamin D during treatment may be protective against COVID-19. Future studies, including randomized control trials, are warranted to determine the effect of vitamin D supplementation on the recovery from COVID-19 in CKD patients.

Effects of Vitamin D Supplementation on COVID-19 Related Outcomes: A Systematic Review and Meta-Analysis

The COVID-19 outbreak has rapidly expanded to a global pandemic; however, our knowledge is limited with regards to the protective factors against this infection. The aim of this systematic literature review and meta-analysis was to evaluate the impact of vitamin D supplementation on COVID-19 related outcomes. A systematic search of relevant papers published until January 2022 was conducted to identify randomized controlled trials (RCTs) and non-randomized studies of intervention (NRISs). The primary outcomes included the risk of COVID-19 infection (primary prevention studies on uninfected individuals), hospital admission (secondary prevention studies on mild COVID-19 cases), and ICU admission and mortality rate (tertiary prevention studies on hospitalized COVID-19 patients). We identified five studies (one RCT, four NRISs) on primary prevention, with five (two RCTs, three NRISs) on secondary prevention, and 13 (six RCTs, seven NRISs) on tertiary prevention. Pooled analysis showed no significant effect on the risk of COVID-19 infection. No meta-analysis was possible on hospitalization risk due to paucity of data. Vitamin D supplementation was significantly associated with a reduced risk of ICU admission (RR = 0.35, 95% CI: 0.20, 0.62) and mortality (RR = 0.46, 95% CI: 0.30, 0.70). Vitamin D supplementation had no significant impact on the risk of COVID-19 infection, whereas it showed protective effects against mortality and ICU admission in COVID-19 patients.

Vitamin D Fortification of Milk Would Increase Vitamin D Intakes in the Australian Population, but a More Comprehensive Strategy Is Required

Low vitamin D status (serum 25-hydroxyvitamin D (25(OH)D) concentration < 50 nmol/L) is prevalent in Australia, ranging between 15% and 32% in the adolescent and adult populations. Vitamin D intakes are also low across the population and were recently estimated at 1.8−3.2 µg/day on average, assuming equal bioactivity of the D vitamers. In combination, these findings strongly suggest that data-driven nutrition policy is needed to increase vitamin D intake and improve status in the Australian population. Food fortification is a potential strategy. We used up-to-date vitamin D food composition data for vitamin D3, 25(OH)D3, vitamin D2, and 25(OH)D2, and nationally representative food and supplement consumption data from the 2011−2013 Australian Health Survey, to model a fortification scenario of 0.8 µg/100 mL vitamin D for fluid dairy milks and alternatives. Under the modelled fortification scenario, the mean vitamin D intake increased by ~2 µg/day from baseline to 4.9 µg/day from food only (7.2 µg/day including supplements). Almost all individual intakes remained substantially below 10 µg/day, which is the Estimated Average Requirement in North America. In conclusion, this modelling showed that fortification of fluid milks/alternatives with vitamin D at the current permitted level would produce a meaningful increase in vitamin D intake, which could be of potential benefit to those with a low vitamin D status. However, this initial step would be insufficient to ensure that most of the population achieves the North American EAR for vitamin D intake. This approach could be included as an effective component of a more comprehensive strategy that includes vitamin D fortification of a range of foods.

Comparison of the cardiovascular system, clinical condition, and laboratory results in COVID-19 patients with and without vitamin D insufficiency

BACKGROUND

Serum vitamin D levels may have a protective role against severe coronavirus disease 2019 (COVID-19). Studies have shown that deficiency in vitamin D may be a significant risk factor for poor outcomes. This study aims to compare the outcome and clinical condition of patients diagnosed with COVID-19 infection considering serum vitamin D levels.

METHODS

In this cross-sectional study, 202 COVID-19 patients without known cardiovascular disease (reduced ejection fraction, uncontrolled arrhythmia, pericardial effusion, cardiac block, valvular disease, or hypertension) were included. Patients were divided into three groups of insufficient (< 30 ng/mL), normal (30 to 50 ng/mL), and high (> 50 ng/mL) serum vitamin D levels. Clinical outcome was defined as severe if invasive respiratory intervention and ICU admission was required.

RESULTS

The patients were divided into three groups based on their vitamin D level: 127 cases in the insufficient vitamin D group, 53 cases in the normal vitamin D group, and 22 cases in the high vitamin D group. The mean age of the population study was 56 years. Thirty-four patients had severe clinical outcomes. The distribution of this group was as follows: 21 patients in the insufficient vitamin D group (16.5%), eight patients in the normal vitamin D group (15.1%), and five patients in the high vitamin D group (22.7%); P = 0.74. No significant differences were found between the groups in terms of mortality rate (P = 0.46). Moreover, the mean of leukocytes (mean ± SD = 6873.5 ± 4236.2), ESR (mean ± SD = 38.42 ± 26.7), and CPK-MB (mean ± SD = 63 ± 140.7) were higher in the insufficient vitamin D group, but it was not statistically significant (P > 0.05).

CONCLUSION

The finding of the present study showed that vitamin D could not make a significant difference in cardiovascular systems, laboratory results, and severity of the disease in COVID-19 patients.

Endocrine and Metabolic Manifestations of COVID-19 Patients Admitted to an Intensive Care Unit

CONTEXT

The effects of coronavirus disease 2019 (COVID-19) on the endocrine system remain uncertain.

OBJECTIVE

Our study aimed to explore the possible effects of COVID-19 on endocrine organs and to determine the impact of glycemic status, 25-hydroxyvitamin D levels, calcium levels, and thyroid dysfunction on the final outcome of patients with COVID-19.

DESIGN AND METHODS

This single-center, retrospective study evaluated endocrine function abnormalities in 102 patients hospitalized with COVID-19 in the intensive care unit (ICU).

RESULTS

 Of 102 patients admitted to ICU, 42 (41.2%) succumbed to illness. The most frequently observed abnormality in thyroid function tests was low free triiodothyronine (FT3) levels (56%). A thyroid profile indicating thyrotoxicosis was detected in five (4.9%) patients, and overt hypothyroidism was identified in two (1.9%) patients. New-onset diabetes was detected in five (4.9%) patients whereas diabetic ketoacidosis at presentation was found in six (5.9%) cases. Rhino-orbital mucormycosis was detected in one patient with diabetes during treatment of COVID-19 while three (2.9%) patients were diagnosed with pulmonary mucormycosis after recovery from COVID-19. Hypocalcemia was observed in 52 (51 %) patients. Out of 42 patients who died, 32 patients had low FT3, 26 patients had high glycated haemoglobin (HbA1c), and 33 patients had low 25-hydroxyvitamin D. Multivariate analysis demonstrated that low concentration of 25-hydroxyvitamin D, low FT3 and higher HbA1c levels were significantly associated with increased mortality.

CONCLUSION

 New-onset thyrotoxicosis in COVID-19 patients is mostly due to subacute thyroiditis. Hypocalcemia is also frequently encountered in patients with moderate disease and those with critical COVID-19. A high index of suspicion is required to timely diagnose mucormycosis in COVID-19 patients with diabetes.

The association between tobacco smoke exposure and vitamin D levels among US general population, 2001-2014: temporal variation and inequalities in population susceptibility

Tobacco smoking is endocrine-disrupting and may interfere with vitamin D endocrine systems (VDES), but supporting evidence is limited and inconsistent. Also, there is a lack of evidence on whether the association between tobacco smoke exposure and VD levels exhibit temporal variation. Data from the National Health and Nutrition Examination Survey was used to evaluate the association between tobacco smoke exposure and VD levels among US general participants from 2001 to 2014. We examined the linear association between serum cotinine and 25(OH)D concentrations, as well as relationship between tobacco smoke exposure categories (active, passive, non-smoking) with VD status (deficiency, inadequacy, sufficiency, intoxication), and assessed whether specific gender, age (3-11, 12-19, 20-59, ≥ 60 years), ethnicity/race, or body mass index (BMI) groups were disproportionately impacted. During 2001-2004, a decrease in both serum cotinine and passive smoking prevalence was observed, with a stabilized active smoking rate. The estimates for the association between tobacco smoke exposure and suboptimal VD levels increased over the study period. Overall results indicated that serum cotinine was negatively associated with 25(OH)D in all participants. Tobacco smoke exposure, including both active and passive smoking exposure, was associated with increased risk of VD deficiency. Moreover, active smoking was additionally related to enhanced risk of VD inadequacy. These associations showed some age and gender differences, with consistent and stronger associations observed in female adults. In contrast, effects of tobacco smoke exposure on VD levels were mostly negative or non-significant among children and adolescents aged 3-19 years. The percentage of US general population with active smoking exposure stabilized over the 14-year period and was still high. Tobacco smoke exposure may disrupt vitamin D levels with an increasing temporal trend in the risk. Our results also provided initial evidence of smoking exposure on VD intoxication, which needs to be further verified. Convincing studies have linked tobacco use exposure, to dysfunctional VDES accompanied with declined serum levels of VD metabolites. However, evidence on the association between tobacco smoke exposure and VD status was rather limited and inconsistent, and there were no researches to date that estimated the temporal variation of the association as well as the effects of smoke exposure on VD intoxication. This study analyzed national survey data, to evaluate the temporal trends in effects of tobacco smoke exposure on VD levels over a decade, and to comprehensively assess the impacts of tobacco smoke exposure on VD levels across specific subgroups. The evidence suggests that the prevalence of active smoking exposure stabilized over the 14-year period and was still high. Moreover, tobacco smoke exposure may disrupt vitamin D levels among general population, with an increasing temporal trend and age-, gender-differences in risk.

Vitamin D and COVID-19 Severity in Hospitalized Older Patients: Potential Benefit of Prehospital Vitamin D Supplementation

Studies involving the associations between vitamin D supplementation taken before the onset of COVID-19 infection and the clinical outcomes are still scarce and this issue remains controversial. This study aimed to assess the relationships between vitamin D (VitD) status and supplementation and coronavirus disease 2019 (COVID-19) severity in older adults (average age of 78 years) hospitalized for COVID-19. We conducted an observational retrospective cohort study with 228 older hospitalized patients during the first wave of the COVID-19 pandemic. The outcomes were in-hospital mortality secondary to COVID-19 or critically severe COVID-19. A logistic regression analysis was conducted to test whether pre-hospital VitD supplementation was independently associated with severity. In this study, 46% of patients developed a severe form and the overall in-hospital mortality was 15%. Sixty-six (29%) patients received a VitD supplement during the 3 months preceding the infection onset. Additionally, a VitD supplement was associated with fewer severe COVID-19 forms (OR = 0.426, p = 0.0135) and intensive care unit (ICU) admissions (OR = 0.341, p = 0.0076). As expected, age > 70 years, male gender and BMI ≥ 35 kg/m2 were independent risk factors for severe forms of COVID-19. No relationship between serum 25(OH)D levels and the severity of the COVID-19 was identified. VitD supplementation taken during the 3 months preceding the infection onset may have a protective effect on the development of severe COVID-19 forms in older adults. Randomized controlled trials and large-scale cohort studies are necessary to strengthen this observation.

Vitamin D: A Role Also in Long COVID-19?

Coronavirus disease 2019 (COVID-19) has quickly become a global pandemic. Reports from different parts of the world indicate that a significant proportion of people who have recovered from COVID-19 are suffering from various health problems collectively referred to as “long COVID-19”. Common symptoms include fatigue, shortness of breath, cough, joint pain, chest pain, muscle aches, headaches, and so on. Vitamin D is an immunomodulatory hormone with proven efficacy against various upper respiratory tract infections. Vitamin D can inhibit hyperinflammatory reactions and accelerate the healing process in the affected areas, especially in lung tissue. Moreover, vitamin D deficiency has been associated with the severity and mortality of COVID-19 cases, with a high prevalence of hypovitaminosis D found in patients with COVID-19 and acute respiratory failure. Thus, there are promising reasons to promote research into the effects of vitamin D supplementation in COVID-19 patients. However, no studies to date have found that vitamin D affects post-COVID-19 symptoms or biomarkers. Based on this scenario, this review aims to provide an up-to-date overview of the potential role of vitamin D in long COVID-19 and of the current literature on this topic.

Long COVID-19 in Children: From the Pathogenesis to the Biologically Plausible Roots of the Syndrome

Long Coronavirus disease-19 (COVID-19) refers to the persistence of symptoms related to the infection with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). This condition is described as persistent and can manifest in various combinations of signs and symptoms, such as fatigue, headache, dyspnea, depression, cognitive impairment, and altered perception of smells and tastes. Long COVID-19 may be due to long-term damage to different organs-such as lung, brain, kidney, and heart-caused by persisting viral-induced inflammation, immune dysregulation, autoimmunity, diffuse endothelial damage, and micro thrombosis. In this review, we discuss the potential and biologically plausible role of some vitamins, essential elements, and functional foods based on the hypothesis that an individual's dietary status may play an important adjunctive role in protective immunity against COVID-19 and possibly against its long-term consequences.

Gastrointestinal symptoms and the severity of COVID-19: Disorders of gut-brain interaction are an outcome

BACKGROUND

Many of the studies on COVID-19 severity and its associated symptoms focus on hospitalized patients. The aim of this study was to investigate the relationship between acute GI symptoms and COVID-19 severity in a clustering-based approach and to determine the risks and epidemiological features of post-COVID-19 Disorders of Gut-Brain Interaction (DGBI) by including both hospitalized and ambulatory patients.

METHODS

The study utilized a two-phase Internet-based survey on: (1) COVID-19 patients' demographics, comorbidities, symptoms, complications, and hospitalizations and (2) post-COVID-19 DGBI diagnosed according to Rome IV criteria in association with anxiety (GAD-7) and depression (PHQ-9). Statistical analyses included univariate and multivariate tests.

RESULTS

Five distinct clusters of symptomatic subjects were identified based on the presence of GI symptoms, loss of smell, and chest pain, among 1114 participants who tested positive for SARS-CoV-2. GI symptoms were found to be independent risk factors for severe COVID-19; however, they did not always coincide with other severity-related factors such as age >65 years, diabetes mellitus, and Vitamin D deficiency. Of the 164 subjects with a positive test who participated in Phase-2, 108 (66%) fulfilled the criteria for at least one DGBI. The majority (n = 81; 75%) were new-onset DGBI post-COVID-19. Overall, 86% of subjects with one or more post-COVID-19 DGBI had at least one GI symptom during the acute phase of COVID-19, while 14% did not. Depression (65%), but not anxiety (48%), was significantly more common in those with post-COVID-19 DGBI.

CONCLUSION

GI symptoms are associated with a severe COVID-19 among survivors. Long-haulers may develop post-COVID-19 DGBI. Psychiatric disorders are common in post-COVID-19 DGBI.

Clinical significance of micronutrient supplements in patients with coronavirus disease 2019: A comprehensive systematic review and meta-analysis

BACKGROUND AND AIMS

Micronutrient supplements such as vitamin D, vitamin C, and zinc have been used in managing viral illnesses. However, the clinical significance of these individual micronutrients in patients with Coronavirus disease 2019 (COVID-19) remains unclear. We conducted this meta-analysis to provide a quantitative assessment of the clinical significance of these individual micronutrients in COVID-19.

METHODS

We performed a comprehensive literature search using MEDLINE, Embase, and Cochrane databases through December 5th, 2021. All individual micronutrients reported by ≥ 3 studies and compared with standard-of-care (SOC) were included. The primary outcome was mortality. The secondary outcomes were intubation rate and length of hospital stay (LOS). Pooled risk ratios (RR) and mean difference (MD) with corresponding 95% confidence intervals (CI) were calculated using the random-effects model.

RESULTS

We identified 26 studies (10 randomized controlled trials and 16 observational studies) involving 5633 COVID-19 patients that compared three individual micronutrient supplements (vitamin C, vitamin D, and zinc) with SOC. Nine studies evaluated vitamin C in 1488 patients (605 in vitamin C and 883 in SOC). Vitamin C supplementation had no significant effect on mortality (RR 1.00, 95% CI 0.62-1.62, P = 1.00), intubation rate (RR 1.77, 95% CI 0.56-5.56, P = 0.33), or LOS (MD 0.64; 95% CI -1.70, 2.99; P = 0.59). Fourteen studies assessed the impact of vitamin D on mortality among 3497 patients (927 in vitamin D and 2570 in SOC). Vitamin D did not reduce mortality (RR 0.75, 95% CI 0.49-1.17, P = 0.21) but reduced intubation rate (RR 0.55, 95% CI 0.32-0.97, P = 0.04) and LOS (MD -1.26; 95% CI -2.27, -0.25; P = 0.01). Subgroup analysis showed that vitamin D supplementation was not associated with a mortality benefit in patients receiving vitamin D pre or post COVID-19 diagnosis. Five studies, including 738 patients, compared zinc intake with SOC (447 in zinc and 291 in SOC). Zinc supplementation was not associated with a significant reduction of mortality (RR 0.79, 95% CI 0.60-1.03, P = 0.08).

CONCLUSIONS

Individual micronutrient supplementations, including vitamin C, vitamin D, and zinc, were not associated with a mortality benefit in COVID-19. Vitamin D may be associated with lower intubation rate and shorter LOS, but vitamin C did not reduce intubation rate or LOS. Further research is needed to validate our findings.

Vitamin D and its possible relationship to neuroprotection in COVID-19: evidence in the literature

Abstract:

Vitamin D is a hormone involved in the regulation of important biological processes such as signal transduction, immune response, metabolic regulation and also in the nervous and vascular systems. To date, coronavirus disease 2019 (COVID-19) infection does not have a specific treatment, however various drugs have been proposed, including those that attenuate the intense inflammatory response and recently the use of vitamin D, in clinical trials, as part of the treatment of COVID-19 has provided promising results. It has been observed in some clinical studies that the use of cholecalciferol (vitamin D3) and its two metabolites the circulating form, calcidiol or calcifediol (25-hydroxycalciferol, 25-(OH)-D) and the active form, calcitriol (1,25-(OH)2-D), in different doses, improve the clinical manifestations, prognosis and survival of patients infected with COVID-19 probably because of its anti-inflammatory, antiviral and lung-protective action. In relation to the central nervous system (CNS) it has been shown, in clinical studies, that vitamin D is beneficial in some neurological and psychiatric conditions because of its anti-inflammatory and antioxidant properties, modulation of neurotransmitters actions, regulation of calcium homeostasis between other mechanisms. It has been showed that COVID-19 infection induces CNS complications such as headache, anosmia, ageusia, neuropathy, encephalitis, stroke, thrombosis, cerebral hemorrhages, cytotoxic lesions and psychiatric conditions and it has been proposed that the use of dietary supplements, as vitamin and minerals, can be adjuvants in this disease. In this review the evidence of possible role of vitamin D, and its metabolites, as protector against the neurological manifestations of COVID-19 was summarized.

Serum 25(OH) Vitamin D Levels in Pregnant Women with Coronavirus Disease 2019 (COVID-19): A Case-Control Study

The physiological changes during pregnancy may increase the risk of complications in pregnant women with coronavirus disease 2019 (COVID-19). Vitamin D is a fat-soluble secosteroid hormone and its role in immunity is appears to be of particular importance in this recent pandemic. Nevertheless, there is little research about the role of vitamin D levels regarding COVID-19 in pregnant women to date. This study aimed to establish a relationship between serum 25-hydroxyvitamin D (25(OH)D) levels in pregnant women and COVID-19. A comparative case-control study was performed with a study population of 256 pregnant women (82 pregnant women with infection and 174 women in control group). Serum 25(OH)D levels were significantly lower in pregnant women with COVID-19 infection than in those without infection. In addition, 89% of COVID-19-positive pregnant women had 25(OH)D deficiency, while in the control group the percentage was 75.30%, finding statistically significant differences (ORa = 2.68; 95% CI 1.19–6.06; p = 0.01). Our results find a relationship between vitamin D deficiency in pregnant women and COVID-19 infection. This finding could be relevant for actual clinical practice. Thus, more research is needed in this field.

Association between vitamin D and bisphenol A levels in an elderly Italian population: results from the InCHIANTI study

OBJECTIVE

This study aimed to evaluate the association between the endocrine-disrupting chemical, bisphenol A (BPA) on circulating levels of 25-hydroxy vitamin D (25(OD)D) and other vitamin D metabolites in an elderly population in Italy.

METHODS

This was a retrospective analysis of the InCHIANTI Biobank in Italy. The association between vitamin D metabolites namely 1,25(OH)D, 25(OH)D, parathyroid hormone (PTH) and BPA levels were evaluated. Multiple regression models were used to examine the association between predictor variables with 1,25(OH)D or 25(OH)D levels.

RESULTS

Samples from 299 individuals aged 72.8 ± 15.7 years were examined. Mean levels of BPA, 1,25(OH)D and 25(OH)D were 351.2 ± 511.6 ng/dL, 43.7 ± 16.9 pg/mL and 20.2 ± 12.1 ng/mL, respectively. One hundred eighty individuals (60.2%) were deficient (<20 ng/mL) in 25(OH)D and this population also presented higher BPA levels (527.9 ± 1289.5 ng/dL vs 86.9 ± 116.8 ng/dL, P < 0.0001). Univariate analysis revealed that BPA levels were negatively correlated with both 1,25(OH)D (r= -0.67, P < 0.0001) and 25(OH)D (r= -0.69, P < 0.0001). Multivariate regression revealed that PTH (β: -0.23, 95% CI: -0.34, -0.13, P < 0.0001) and BPA (β: -0.25, 95% CI: -0.3, -0.19, P < 0.0001) remained significantly associated with 25(OH)D levels while BPA was also associated with 1,25(OH)D levels (β: -0.19, 95% CI: -0.22, -0.15, P < 0.0001). Receiver operating characteristic curve analysis showed that a BPA concentration of >113 ng/dL was the best cut-off to predict individuals deficient in 25(OH)D (area under the curve: 0.87, 95% CI: 0.82-0.90, P < 0.0001).

CONCLUSION

The strong negative association between BPA and vitamin D in this elderly population warrants further investigation, particularly since this population is already at greatest risk of hypovitaminosis and fracture.

The Role of Vitamin D in COVID-19 and the Impact of Pandemic Restrictions on Vitamin D Blood Content

Vitamin D is a hormone regulating the immune system and playing a pivotal role in responses to microbial infections. It regulates inflammatory processes by influencing the transcription of immune-response genes in macrophages, T cells, and dendritic cells. The proven role of vitamin D in many infectious diseases of the respiratory tract indicated that vitamin D should also play a role in SARS-CoV-2 infection. Vitamin D inhibits cytokine storm by switching the pro-inflammatory Th1 and Th17 to the anti-inflammatory Th2 and Treg response. Vitamin D is therefore expected to play a role in preventing, relieving symptoms, or treating SARS-CoV-2 infection symptoms, including severe pneumonia. There are several possible mechanisms by which vitamin D may reduce the risk of COVID-19 infection, such as induction of the transcription of cathelicidin and defensin. Also a nongenomic antiviral action of vitamin D and lumisterol, the molecule closely related to vitamin D, was reported. Despite this enormous progress, currently, there is still insufficient scientific evidence to support the claim that vitamin D supplementation may help treat COVID-19 infection. The pandemic restrictions were also shown to impact vitamin D uptake by limiting exposure to sunlight.

Association of vitamin D deficiency with COVID-19 severity and mortality in Iranian people: a prospective observational study

Background

As the coronavirus disease 2019 (COVID-19) pandemic continues to escalate, it is important to identify the prognostic factors related to increased mortality and disease severity. To assess the possible associations of vitamin D level with disease severity and survival, we studied 248 hospitalized COVID-19 patients in a single center in a prospective observational study from October 2020 to May 2021 in Tehran, Iran.

Methods

Patients who had a record of their 25-hydroxyvitamin D level measured in the previous year before testing positive with COVID-19 were included. Serum 25-hydroxyvitamin D level was measured upon admission in COVID-19 patients. The associations between clinical outcomes of patients and 25-hydroxyvitamin D level were assessed by adjusting for potential confounders and estimating a multivariate logistic regression model.

Results

The median (interquartile range) age of patients was 60 years (44–74 years), and 53% were male. The median serum 25-hydroxyvitamin D level prior to admission decreased with increasing COVID-19 severity (P=0.009). Similar findings were obtained when comparing median serum 25-hydroxyvitamin D on admission between moderate and severe patients (P=0.014). A univariate logistic regression model showed that vitamin D deficiency prior to COVID-19 was associated with a significant increase in the odds of mortality (odds ratio, 2.01; P=0.041). The multivariate Cox model showed that vitamin D deficiency on admission was associated with a significant increase in risk for mortality (hazard ratio, 2.35; P=0.019).

Conclusions:

Based on our results, it is likely that deficient vitamin D status is associated with increased mortality in COVID-19 patients. Thus, evaluating vitamin D level in COVID-19 patients is warranted.

Nutrition and a Balanced Diet in the Elderly During the COVID-19 Pandemic

Background:

Age is an important risk factor in the mortality ratio of the COVID-19 disease and mostly, the hospitalised patients over 60 years with chronic diseases are at high risk of death. With preventive measures, proper nutrient intake might be helpful to maintain a healthy state or reduce the severity of the COVID-19 disease in the elderly.

Methods:

Database searches of PubMed, Scopus, Medline, Google Scholar and Web of Science were performed by the following terms of pandemic; COVID-19; coronavirus; elderly; elderly nutrition.

Results:

The requirement of some macro and micro nutrients increases especially the nutrients that support the immune activity. During the pandemic, the daily energy requirement for the elderly is stated as 27-30 kcal/kg while the protein intake is recommended as at least 1g/kg, and the ratio of fat and carbohydrate is 30:70 or 50:50. The daily intake of Vitamin A, B6, B12, C, D, zinc and selenium can also be increased due to their supporting function in the immune system. Probiotics such as Bifidobacterium longum MM-2, Lactobacillus plantarum 06CC2, Lactobacillus bulgaricus OLL1073R-1 and Lactobacillus rhamnosus M21 and the consumption of prebiotics in diet enhance the immune function. Additionally, flavonoids such as baicalin, epigallocatechin gallate, gallocatechin gallate, kaempferol, luteolin, resveratrol and quercetin improve immunity by reducing oxidative stress in the elderly.

Conclusion:

Adequate and balanced nutrition should be provided during the pandemic; in addition to this, micronutrient deficiencies should also be prevented in this period in the elderly at every stage of life.

Association of vitamin D deficiency with COVID-19 infection severity: Systematic review and meta-analysis

BACKGROUND

We sought to evaluate the association between vitamin D deficiency and the severity of coronavirus disease 2019 (COVID-19) infection.

METHODS

Multiple databases from 1 January 2019 to 3 December 2020 were searched for observational studies evaluating the association between vitamin D deficiency and severity of COVID-19 infection. Independent reviewers selected studies and extracted data for the review. The main outcomes of interest were mortality, hospital admission, length of hospital stay and intensive care unit admission.

RESULTS

Seventeen observational studies with 2756 patients were included in the analyses. Vitamin D deficiency was associated with significantly higher mortality (odds ratio [OR]: 2.47, 95% confidence interval [CI]: 1.50-4.05; 12 studies; hazard ratio [HR]: 4.11, 95% CI: 2.40-7.04; 3 studies), higher rates of hospital admissions (OR: 2.18, 95% CI: 1.48-3.21; 3 studies) and longer hospital stays (0.52 days; 95% CI: 0.25-0.80; 2 studies) as compared to nonvitamin D deficient status. Subgroup analyses based on different cut-offs for defining vitamin D deficiency, study geographic locations and latitude also showed similar trends.

CONCLUSIONS

Vitamin D deficiency is associated with greater severity of COVID-19 infection. Further studies are warranted to determine if vitamin D supplementation can decrease the severity of COVID-19.

Vitamin D supplementation and Covid‐19 outcomes: A systematic review, meta‐analysis and meta‐regression

Vitamin D has many protective properties and potential role against acute lung injury. Low serum vitamin D is associated with high risk of pneumonia and development of acute respiratory distress syndrome. This study sought to analyse the efficacy of vitamin D in improving the outcomes of coronavirus disease 2019 (Covid‐19) patients. Using specific keywords, we comprehensively searched the potential articles on PubMed, Europe PMC and ClinicalTrials.gov database until 8th May 2021. All published studies on Covid‐19 and vitamin D were retrieved. Statistical analysis was conducted using Review Manager 5.4 software. A total of 11 studies with 22,265 Covid‐19 patients were included in the meta‐analysis. Our data suggested that vitamin D supplementation was associated with reduction in intensive care unit admission rate (OR 0.27; 95% CI: 0.09–0.76, p  = 0.010, I 2 = 70%, random‐effect modelling); reduction of the need for mechanical ventilation (OR 0.34; 95% CI: 0.16–0.72, p  = 0.005, I 2 = 61%, random‐effect modelling) and reduction of mortality from Covid‐19 (OR 0.37; 95% CI: 0.21–0.66, p  < 0.001, I 2 = 50%, random‐effect modelling). Further analysis showed that the associations were influenced by age (p  = 0.020). Our study suggests that vitamin D supplementation may offer beneficial effects on Covid‐19 outcomes. However, more randomized clinical trials are required to confirm this conclusion.

Rethinking COVID-19 and Beyond: Prevention, Remedies, and Recovery

In a relatively short timeframe, millions of deaths and illnesses associated with COVID-19 have been reported, accompanied by substantial economic losses, and overall, negatively impacting society. This experience should serve as a wakeup call to those in public health and healthcare, along with politicians and citizens: COVID-19 is considered a predictable and preventable disaster. While various reactive responses to address the pandemic were implemented, some with adverse effects, proactive measures in the years before COVID-19 were neglected. Predominately this involved the development of a preventable overfat pandemic, which played a key role in both rising rates of chronic disease, the comorbidities that increase the risk for COVID-19, along with associated inflammation and malnutrition. This increased the risk of infection in billions of people worldwide, which, in essence, primed society for high rates of COVID-19 infection. Excess body fat evolves primarily from poor nutrition, particularly the overconsumption of sugar and other refined carbohydrates, which replace the vital nutrients needed for optimal immune function. Sugar and refined carbohydrates must be considered the new tobacco, as these foods are also devoid of nutrients, and underly inflammatory chronic diseases. A balanced diet of nutrient-dense wholefood must be emphasized to combat infectious and inflammatory diseases. Implementing proactive preventive lifestyle changes must begin now, starting with simple, safe, and inexpensive dietary modifications that can quickly lead to a healthier population.

Populations in Low-Magnesium Areas Were Associated with Higher Risk of Infection in COVID-19's Early Transmission: A Nationwide Retrospective Cohort Study in the United States

Many studies have confirmed the important roles of nutritional status and micronutrients in the COVID-19 pandemic. Magnesium is a vital essential trace element that is involved in oxidative stress, inflammation, and many other immunological functions and has been shown to be associated with the outcome of COVID-19 infection. Here, we conducted a nationwide retrospective cohort study in the United States involving 1150 counties, 287,326,503 individuals, and 5,401,483 COVID-19 confirmed cases as of 30 September 2020 to reveal the infection risk of the populations distributed in low-magnesium areas in the early transmission of COVID-19. Our results indicate that the average county-level COVID-19 cumulative incidence in low-magnesium areas was significantly higher than in the control areas. Additionally, a significant negative nonlinear association was found between environmental magnesium concentration and the county-level COVID-19 cumulative incidence. Furthermore, the populations distributed in low environmental magnesium areas faced a higher COVID-19 infection risk (RR: 1.066; CI: 1.063-1.068), among which females (RR: 1.07; CI: 1.067-1.073), the 0-17 years subgroup (RR: 1.125; CI: 1.117-1.134), the 65+ years subgroup (RR: 1.093; CI: 1.087-1.098), black people (RR: 1.975; CI: 1.963-1.986), populations outside metro areas, and counties with a smaller population experienced higher risk of infection by COVID-19 than other subgroups. Considering that the magnesium intake of about half the population of the United States is below the daily required dose, our study will contribute to the creation of long-term public health strategies to help protect against COVID-19.

The impact of the COVID-19 pandemic on lifestyle behaviors in children and adolescents: an international overview

The adverse effects of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) are not limited to the related infectious disease. In children and adolescents, serious risks due to the coronavirus disease 2019 (COVID-19) pandemic are also related to its indirect effects. These include an unbalanced diet with an increased risk of weight excess or nutritional deficiencies, increased sedentary lifestyle, lack of schooling, social isolation, and impaired mental health.Pediatricians should be aware of the side effects of the COVID-19 pandemic on children's diet, physical mental health and advise the families according to their nutritional needs and financial resources. Moreover, the lack of a targeted therapy able to offer protection against the deleterious effects of SARS-CoV-2 infection should require a greater effort by scientific societies to find a more effective prevention strategy. In this context, much interest should be given to nutritional support, able to contrast malnutrition and to stimulate the immune system.

Foods to deliver immune-supporting nutrients

PURPOSE OF REVIEW

This article will briefly describe the role of specific dietary components, mainly micronutrients, in supporting the immune response and summarise the literature regarding foods and dietary patterns in the context of immunity and infectious illness. Literature on SARS-COV-2 infection and COVID-19 is referred to where appropriate.

RECENT FINDINGS

Micronutrients, other nutrients and plant bioactives have roles in supporting the immune response. Low status of a number of micronutrients is associated with increased risk and severity of COVID-19. Recent studies report associations of plant-based diets with lower risk of, and less severe, COVID-19.

SUMMARY

In order to support the immune response, sufficient amounts of a range of essential and non-essential nutrients and other bioactives, mainly from a plant-based diet should be consumed. Further research should define cause-and-effect relationships of intakes of individual dietary components and foods, and of dietary patterns with susceptibility to, and severity of, viral infections.

Vitamin D attenuates COVID-19 complications via modulation of proinflammatory cytokines, antiviral proteins, and autophagy

INTRODUCTION

Global emergence of coronavirus disease-19 (COVID-19) has clearly shown variable severity, mortality, and frequency between and within populations worldwide. These striking differences have made many biological variables attractive for future investigations. One of these variables, vitamin D, has been implicated in COVID-19 with rapidly growing scientific evidence.

AREAS COVERED

The review intended to systematically explore the sources, and immunomodulatory role of vitamin D in COVID-19. Search engines and data sources including Google Scholar, PubMed, NCBI, Scopus, and Web of Science were used for data collection. The search terms used were Vitamin D, COVID-19, immune system, and antiviral mechanism. Overall, 232 sources of information were collected and 188 were included in this review.

EXPERT OPINION

Interaction of vitamin D and vitamin D receptor (VDR) triggers the cellular events to modulate the immune system by regulation of many genes. Vitamin D operates as a double-edged sword against COVID-19. First, in macrophages, it promotes the production of antimicrobial and antiviral proteins like β-defensin 2 and cathelicidin, and these proteins inhibit the replication of viral particles and promote the clearance of virus from the cells by autophagy. Second, it suppresses cytokine storm and inflammatory processes in COVID-19.

Is There a Crucial Link Between Vitamin D Status and Inflammatory Response in Patients With COVID-19?

Background

Hypovitaminosis D has been suggested to play a possible role in coronavirus disease 2019 (COVID-19) infection.

Methods

The aim of this study is to analyze the relationship between vitamin D status and a biochemical panel of inflammatory markers in a cohort of patients with COVID-19. A secondary endpoint was to evaluate the correlation between 25OHD levels and the severity of the disease. Ninety-three consecutive patients with COVID-19-related pneumonia were evaluated from March to May 2020 in two hospital units in Pisa, in whom biochemical inflammatory markers, 25OHD levels, P/F ratio at nadir during hospitalization, and complete clinical data were available.

Results

Sixty-five percent of patients presented hypovitaminosis D (25OHD ≤ 20 ng/ml) and showed significantly higher IL-6 [20.8 (10.9-45.6) vs. 12.9 (8.7-21.1) pg/ml, p = 0.02], CRP [10.7 (4.2-19.2) vs. 5.9 (1.6-8.1) mg/dl, p = 0.003], TNF-α [8.9 (6.0-14.8) vs. 4.4 (1.5-10.6) pg/ml, p = 0.01], D-dimer [0.53 (0.25-0.72) vs. 0.22 (0.17-0.35) mg/l, p = 0.002], and IL-10 [3.7 (1.8-6.9) vs. 2.3 (0.5-5.8) pg/ml, p = 0.03]. A significant inverse correlation was found between 25OHD and all these markers, even adjusted for age and sex. Hypovitaminosis D was prevalent in patients with severe ARDS, compared with the other groups (75% vs. 68% vs. 55%, p < 0.001), and 25OHD levels were lower in non-survivor patients.

Conclusions

The relationship between 25OHD levels and inflammatory markers suggests that vitamin D status needs to be taken into account in the management of these patients. If vitamin D is a marker of poor prognosis or a possible risk factor with beneficial effects from supplementation, this still needs to be elucidated.

The Prognostic Role of Metabolic and Endocrine Parameters for the Clinical Severity of COVID-19

OBJECTIVE

An outbreak of coronavirus disease-19 (COVID-19) began in December 2019 and spread globally, overwhelming the entire world. COVID-19 is a public health emergency of international concern. Due to its high morbidity and mortality rate, recognition of its risk and prognostic factors is important. We aimed to understand the relationship between metabolic and endocrine parameters and the prognosis of COVID-19.

METHODS AND MATERIALS

This was a cross-sectional clinical study. A total of 70 patients with severe COVID-19 were enrolled. Laboratory results at the first admission time (including complete blood count, C-reactive protein, lactate dehydrogenase, blood glucose, calcium, phosphate, albumin, creatinine, magnesium, lipid profiles, liver enzymes, thyroid hormones, cortisol, and vitamin D) and outcome data were recorded. We divided patients into (1) intensive care unit- (ICU-) admitted and non-ICU-admitted and (2) survivors and nonsurvivors for estimation of severity and prognosis. We determined the risk factors associated with critical illness and poor prognosis.

RESULTS

Patients with higher white blood cell (WBC) count and phosphate levels had significantly higher ICU admission rates. According to univariate analysis, serum levels of T3, phosphate, and WBC as well as the duration of hospitalization were associated with mortality. Multivariate analysis revealed that only WBC and duration of hospitalization were independent predictors for mortality rate in COVID-19 patients.

CONCLUSION

Our findings suggest that longer duration of hospitalization and higher WBC count are associated with poor outcomes in patients with COVID-19.

Vitamin D supplementation and COVID-19 risk: a population-based, cohort study

PURPOSE

To analyze the associations between cholecalciferol or calcifediol supplementation, serum 25-hydroxyvitamin D (25OHD) levels and COVID-19 outcomes in a large population.

METHODS

All individuals ≥ 18 years old living in Barcelona-Central Catalonia (n = 4.6 million) supplemented with cholecalciferol or calcifediol from April 2019 to February 2020 were compared with propensity score-matched untreated controls. Outcome variables were SARS-CoV2 infection, severe COVID-19 and COVID-19 mortality occuring during the first wave of the pandemic. Demographical data, comorbidities, serum 25OHD levels and concomitant pharmacological treatments were collected as covariates. Associations between cholecalciferol or calcifediol use and outcome variables were analyzed using multivariate Cox proportional regression.

RESULTS

Cholecalciferol supplementation (n = 108,343) was associated with slight protection from SARS-CoV2 infection (n = 4352 [4.0%] vs 9142/216,686 [4.2%] in controls; HR 0.95 [CI 95% 0.91-0.98], p = 0.004). Patients on cholecalciferol treatment achieving 25OHD levels ≥ 30 ng/ml had lower risk of SARS-CoV2 infection, lower risk of severe COVID-19 and lower COVID-19 mortality than unsupplemented 25OHD-deficient patients (56/9474 [0.6%] vs 96/7616 [1.3%]; HR 0.66 [CI 95% 0.46-0.93], p = 0.018). Calcifediol use (n = 134,703) was not associated with reduced risk of SARS-CoV2 infection or mortality in the whole cohort. However, patients on calcifediol treatment achieving serum 25OHD levels ≥ 30 ng/ml also had lower risk of SARS-CoV2 infection, lower risk of severe COVID-19, and lower COVID-19 mortality compared to 25OHD-deficient patients not receiving vitamin D supplements (88/16276 [0.5%] vs 96/7616 [1.3%]; HR 0.56 [CI 95% 0.42-0.76], p < 0.001).

CONCLUSIONS

In this large, population-based study, we observed that patients supplemented with cholecalciferol or calcifediol achieving serum 25OHD levels ≥ 30 ng/ml were associated with better COVID-19 outcomes.

Vitamin D supplementation and clinical outcomes in COVID-19: a systematic review and meta-analysis

PURPOSE

To provide a precise summary and collate the hitherto available clinical evidence on the effect of vitamin D supplementation on clinical outcomes in COVID-19 patients.

METHODS

PubMed/MEDLINE, Scopus, and Web of Science databases were systematically searched using appropriate keywords till June 8, 2021, to identify observational studies and randomized controlled trials (RCTs) reporting adverse clinical outcomes (ICU admission and/or mortality) in COVID-19 patients receiving vitamin D supplementation vs. those not receiving the same. Both prior use and use of vitamin D after COVID-19 diagnosis were considered. Unadjusted/adjusted pooled odds ratio (OR) with 95% confidence intervals (CI) were calculated (PROSPERO registration number CRD42021248488).

RESULTS

We identified 13 studies (10 observational, 3 RCTs) pooling data retrieved from 2933 COVID-19 patients. Pooled analysis of unadjusted data showed that vitamin D use in COVID-19 was significantly associated with reduced ICU admission/mortality (OR 0.41, 95% CI: 0.20, 0.81, p = 0.01, I2 = 66%, random-effects model). Similarly, on pooling adjusted risk estimates, vitamin D was also found to reduce the risk of adverse outcomes (pooled OR 0.27, 95% CI: 0.08, 0.91, p = 0.03, I2 = 80%, random-effects model). Subgroup analysis showed that vitamin D supplementation was associated with improved clinical outcomes only in patients receiving the drug post-COVID-19 diagnosis and not in those who had received vitamin D before diagnosis.

CONCLUSIONS

Vitamin D supplementation might be associated with improved clinical outcomes, especially when administered after the diagnosis of COVID-19. However, issues regarding the appropriate dose, duration, and mode of administration of vitamin D remain unanswered and need further research.

Evaluation of the relationship between serum levels of zinc, vitamin B12, vitamin D, and clinical outcomes in patients with COVID-19

Due to the known anti-inflammatory and antiviral effects of zinc, 25(OH)D, and vitamin B12, in this study, we explored the association between serum levels of these micronutrients in coronavirus disease 2019 (COVID-19) patients at the time of admission and the clinical outcomes. This study was carried out on 293 patients with COVID-19, who were hospitalized at Imam Hassan hospital (Bojnourd, Iran). We collected demographic data, clinical characteristics, values of serum biochemical parameters in the first week of admission, and clinical outcomes from electronic medical records. We also measured serum levels of zinc, 25(OH)D, and vitamin B12 within 3 days of admission. Of the 293 hospitalized, the median age was 53 years, and 147 (50.17%) were female. Thirty-seven patients (12.62%) were admitted to the intensive care unit (ICU), and forty-two (14.32%) died. We found that the serum levels of zinc, vitamin B12, and 25(OH)D were lower in patients who died than those who were admitted to ICU or non-ICU and survived; however, these differences were not statistically significant for vitamin B12 and 25(OH)D (p > 0.05). The serum concentrations of zinc, vitamin B12, and 25(OH)D at the time of admission did not affect the length of hospital stay in patients with COVID-19. In general, it seems that serum levels of 25(OH)D, vitamin B12, and especially zinc at the time of admission can affect clinical outcomes in COVID-19 patients.

Seasonal UV exposure and vitamin D: association with the dynamics of COVID-19 transmission in Europe

Several recent studies have demonstrated that low plasma 25(OH) vitamin D levels are associated with the risk of COVID-19 infection. The primary source of vitamin D production in humans is environmental UV radiation. In many viral respiratory diseases, peak infection rates are observed during winter due to reduced UV exposure and low temperatures. In Europe, the second wave of COVID-19 began early in the winter of 2020. Investigating the impact of seasonal temperature and UV exposure on COVID-19 transmission could thus aid in prevention and intervention. As such, we first performed a comprehensive meta-analysis of all related published literature based on the association between vitamin D and COVID-19, which supported the hypothesis that the low vitamin D level is a critical risk factor for COVID-19 infection. Next, to understand the potential impact of seasonal UV and temperature levels on COVID-19 cases, we analyzed meteorological data and daily COVID-19 cases per million in the populations of 26 European countries. We observed that low temperature, UV index, and cloud-free vitamin D UV dose (UVDVF) levels are negatively correlated with COVID-19 prevalence in Europe. Furthermore, a distributed lag nonlinear model was used to assess the nonlinear delayed effects of individual seasonal factors on COVID-19 cases. Such analysis highlighted the significantly delayed impact of UVDVF on the cumulative relative risk of COVID-19 infection. The findings of this study suggest that low UV exposure can affect the required production of vitamin D in the body, which substantially influences the dynamics of COVID-19 transmission and severity.