Association between 25-hydroxyvitamin D levels and COVID-19 severity

Unveiling the Interplay-Vitamin D and ACE-2 Molecular Interactions in Mitigating Complications and Deaths from SARS-CoV-2

The interaction of the SARS-CoV-2 spike protein with membrane-bound angiotensin-converting enzyme-2 (ACE-2) receptors in epithelial cells facilitates viral entry into human cells. Despite this, ACE-2 exerts significant protective effects against coronaviruses by neutralizing viruses in circulation and mitigating inflammation. While SARS-CoV-2 reduces ACE-2 expression, vitamin D increases it, counteracting the virus's harmful effects. Vitamin D's beneficial actions are mediated through complex molecular mechanisms involving innate and adaptive immune systems. Meanwhile, vitamin D status [25(OH)D concentration] is inversely correlated with severity, complications, and mortality rates from COVID-19. This study explores mechanisms through which vitamin D inhibits SARS-CoV-2 replication, including the suppression of transcription enzymes, reduced inflammation and oxidative stress, and increased expression of neutralizing antibodies and antimicrobial peptides. Both hypovitaminosis D and SARS-CoV-2 elevate renin levels, the rate-limiting step in the renin-angiotensin-aldosterone system (RAS); it increases ACE-1 but reduces ACE-2 expression. This imbalance leads to elevated levels of the pro-inflammatory, pro-coagulatory, and vasoconstricting peptide angiotensin-II (Ang-II), leading to widespread inflammation. It also causes increased membrane permeability, allowing fluid and viruses to infiltrate soft tissues, lungs, and the vascular system. In contrast, sufficient vitamin D levels suppress renin expression, reducing RAS activity, lowering ACE-1, and increasing ACE-2 levels. ACE-2 cleaves Ang-II to generate Ang(1-7), a vasodilatory, anti-inflammatory, and anti-thrombotic peptide that mitigates oxidative stress and counteracts the harmful effects of SARS-CoV-2. Excess ACE-2 molecules spill into the bloodstream as soluble receptors, neutralizing and facilitating the destruction of the virus. These combined mechanisms reduce viral replication, load, and spread. Hence, vitamin D facilitates rapid recovery and minimizes transmission to others. Overall, vitamin D enhances the immune response and counteracts the pathological effects of SARS-CoV-2. Additionally, data suggests that widely used anti-hypertensive agents-angiotensin receptor blockers and ACE inhibitors-may lessen the adverse impacts of SARS-CoV-2, although they are less potent than vitamin D.

Impact of 25-hydroxy vitamin D levels in severe acute respiratory syndrome coronavirus 2 patients with respect to clinical and biochemical profile: An experience from a tertiary care hospital

INTRODUCTION

Among the many micronutrients, Vitamin D deficiency has been associated with the severity of Severe Acute Respiratory Syndrome Coronavirus 2 patients.

DESIGN AND METHODS

A retrospective observational study was conducted on Severe acute respiratory syndrome coronavirus 2 patients admitted to a tertiary care hospital between April 5, 2021, and May 5, 2021.

RESULTS

Among 285 patients,77.2 % of the patients who stayed for more than 14 days were either Vitamin D insufficient or deficient [P value < 0.05]. In our study, the mean oxygen saturation at admission was 85.7 % in the Vitamin D deficiency group compared to 95.6 % in Vitamin D sufficiency patients [P value < 0.05]. Mean serum ferritin was 398 ng/ml in the Vitamin D deficiency group compared to 393 ng/ml in Vitamin D sufficiency patients [P value > 0.05]. The mean C-reactive protein was 107.6 mg/ml in the Vitamin D deficiency group compared to 21.8 ng/ml in Vitamin D sufficiency patients [P value < 0.05]. The mean D-Dimer was 2268 ng/ml in the Vitamin D deficiency group compared to 781 ng/ml in Vitamin D sufficiency patients [P value < 0.05]. In the non-survivor group,97.4 % were Vitamin D deficient and insufficient. Only 2 % of the patients who survived were Vitamin D deficient [P value < 0.05].

CONCLUSION

We observed that low 25-hydroxy Vitamin D levels were associated with lower oxygen saturation and higher acute physiology and chronic health evaluation II scores, requiring a more extended stay in the hospital. C-reactive protein and D-dimers were significantly higher in Vitamin D deficient patients, suggesting severe disease. We did not find statistically significant findings in the case of the correlation of serum ferritin levels with Vitamin D status.

Vitamin D/Bone Mineral Density and Triglyceride Paradoxes Seen in African Americans: A Cross-Sectional Study and Review of the Literature

Vitamin D is known to have a positive effect on bone health. Despite the greater frequency of vitamin D deficiency in African Americans (AA), they have a higher bone mineral density (BMD) compared to whites, demonstrating a disconnect between BMD and vitamin D levels in AA. Another intriguing relationship seen in AA is the triglyceride (TG) paradox, an unusual phenomenon in which a normal TG status is observed even when patients house conditions known to be characterized by high TG levels, such as Type II diabetes. To the best of our knowledge, no study has examined whether these two paradoxical relationships exist simultaneously in AA subjects with Type II diabetes. In this study, we compared levels of blood markers, including HbA1c, TG, and vitamin D, measured as serum 25-hydroxyvitamin D [25(OH)VD] µM/mL, [25(OH)VD]/TG, calcium, and BMD in AA (n = 56) and white (n = 26) subjects with Type II diabetes to see whether these relationships exist concurrently. We found that AA subjects had significantly lower TG and [25(OH)VD] levels and a significantly higher BMD status compared to white subjects, even when the ages, BMI, duration of diabetes, HbA1c, and calcium levels were similar between the two groups. This demonstrates that these two paradoxical relationships exist simultaneously in Type II diabetic AA subjects. In addition to these findings, we discuss the current hypotheses in the literature that attempt to explain why these two intriguing relationships exist. This review also discusses four novel hypotheses, such as altered circulating levels and the potential role of estrogen and hydrogen sulfide on BMD and HMG-CoA reductase as a possible contributor to the TG paradox in AA subjects. This manuscript demonstrates that there are still many unanswered questions regarding these two paradoxical relationships and further research is needed to determine why they exist and how they can be implemented to improve healthcare.

Association between 25-OH Vitamin D Deficiency and COVID-19 Severity in Pregnant Women

Evidence from studies in the general population suggests an association between vitamin D insufficiency/deficiency and COVID-19 susceptibility and disease severity. The present study was performed on 165 third-trimester pregnant women at the time of delivery. Seventy-nine women tested negative for SARS-CoV-2. From 86 women testing positive, 32 were asymptomatic, 44 presented a mild form of the disease, and 10 experienced severe symptoms. Serum 25-OH vitamin D levels were measured on blood samples collected on admission. Low vitamin D levels were detected in symptomatic but not asymptomatic COVID-19 patients compared to healthy women (p = 0.0227). In addition, 20 (45.4%) pregnant women in the mild COVID-19 group and 6 (60%) in the severe group were vitamin D deficient (p = 0.030). On the other hand, lasso regression analysis showed that 25-OH vitamin D deficiency is an independent predictor of severe COVID-19 with an odds ratio (OR) of 5.81 (95% CI: 1.108-30.541; p = 0.037). These results show the relationship between vitamin D deficiency in pregnant women and the severity of COVID-19 infection and support the recommendation to supplement with vitamin D to avoid worse COVID-19 outcomes during pregnancy.

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.

Clinical and Prognostic Significance of Baseline Serum Vitamin D Levels in Hospitalized Egyptian Covid-19 Patients

BACKGROUND AND AIM

Vitamin D is a hormone with essential roles in both cellular metabolism and immunity. It controls calcium homeostasis and modulates innate and adaptive immune system responses. Many studies suggested an association between vitamin D deficiency and clinical outcomes of covid-19 infection, while others failed to document such a relation. The present study aimed to evaluate the clinical and prognostic significance of baseline vitamin D levels in hospitalized Egyptian covid-19 patients.

PATIENTS AND METHODS

The present retrospective study included 300 hospitalized covid-19 patients. Patients were submitted to standard clinical, laboratory, and radiological assessment. According to vitamin D levels, patients were classified to have normal levels (≥30), insufficient levels (20-29) or deficient levels (<20).

RESULTS

According to their vitamin D levels, patients were classified into those with normal vitamin D (n=135), others with vitamin D insufficiency (n=114), and a third group with vitamin D deficiency (n=51). Patients with normal vitamin D levels and vitamin D insufficiency are significantly younger [median (IQR): 49.0 (39.0-57.0) versus 51.0 (40.0-61.0) and 55.0 (43.0-62.0) years, respectively, p=0.012] and had less frequency of severe disease (24.4% versus 40.4% and 51.0%, respectively) when compared with those with vitamin D deficiency. Moreover, they had significantly lower levels of D dimer [median (IQR): 1.5 (0.9-2.5) versus 1.8 (0.9-3.1) and 2.0 (1.0-3.2)], CRP [median (IQR): 58.0 (30.0-120.0) versus 76.0 (42.5-160.0) and 105.0 (74.0-208.0), respectively, p<0.001], ferritin [median (IQR): 458.0 (240.0-759.0) versus 606.0 (433.8-897.8) and 820.0 (552.0-1087.0), respectively, p<0.001], and procalcitonin [median (IQR): 290.0 (152.0-394.0) versus 372.5 (227.0-530.5) and 443.0 (272.0-575.0), respectively, p<0.001]. Only lower vitamin D levels were significant predictors of mortality in multivariate analysis [OR (95% CI): 0.88 (0.84-0.92), p<0.001].

CONCLUSION

Low vitamin D levels are related to exaggerated inflammatory response, disease severity, and poor clinical outcome in hospitalized covid-19 patients.