Vitamin D and Stroke: Effects on Incidence, Severity, and Outcome and the Potential Benefits of Supplementation

The Effect of Vitamin D Supplementation on Functional Outcomes in Patients Undergoing Rehabilitation After an Ischemic Stroke: A Prospective, Single-Blind, Randomized, Placebo-Controlled Study

Background/Objectives: A vitamin D deficiency is prevalent in post-stroke patients and may impair neurological recovery. While observational studies highlight the neuroprotective role of vitamin D, there is limited evidence from interventional studies evaluating its impact on functional recovery during stroke rehabilitation. This study aimed to assess whether daily vitamin D3 supplementation enhances functional recovery. Methods: This prospective, randomized, placebo-controlled, single-blind study included 159 patients (mean age: 62.5 ± 8.4 years) with a first ischemic stroke that were admitted for early rehabilitation. The participants were randomly allocated to receive 2000 IU of vitamin D3 daily (n = 79) or a placebo (n = 80) for six weeks. The functional outcomes were measured using the Barthel index (BI) and modified Rankin scale (mRS) at baseline and after 42 days. The serum 25-hydroxyvitamin D [25(OH)D] and insulin-like growth factor 1 (IGF-1) levels were analyzed. Results: Vitamin D3 supplementation significantly increased the serum 25(OH)D levels (p < 0.001). Supplementation was associated with improved BI scores (β = 0.07, p = 0.006). A higher BMI (β = -0.06, p = 0.033), higher NIHSS scores (β = -0.18, p = 0.036), hypertension, and statin use negatively impacted functional recovery. Anticoagulant use was correlated with higher mRS scores, indicating greater disability (p = 0.04). Conclusions: Vitamin D3 supplementation positively influences the functional outcomes during post-stroke rehabilitation, supporting its potential role in enhancing neuroplasticity and recovery. Larger multi-center trials are needed to confirm these findings and optimize vitamin D supplementation strategies.

Vitamin D and cardiovascular outcomes in multiple sclerosis

BACKGROUND

Vitamin D (25(OH)D) deficiency is linked to increased cardiovascular disease (CVD) risk in the general population, but its implications for people with multiple sclerosis (pwMS) remain unexplored. This study aimed to evaluate the association of 25(OH)D with long-term CVD outcomes in pwMS and the impact of vitamin D supplementation.

METHODS

This observational cohort study analysed anonymised medical records from 70 healthcare organisations following pwMS for 5-years (2019-2024). PwMS and deficient or inadequate 25(OH)D levels were 1:1 propensity-score matched with pwMS and adequate 25(OH)D levels, for demographics, comorbidities, and cardiovascular care. Cox proportional hazard models analysed the incidence of all-cause mortality, stroke, acute myocardial infarction, heart failure, angina, atrial fibrillation/flutter, and a composite measure of major adverse cardiovascular events (MACE). Propensity-matched pwMS who had deficient or inadequate 25(OH)D levels taking cholecalciferol were compared to pwMS and adequate 25(OH)D levels (not taking supplementation).

RESULTS

Amongst 74,372 pwMS, 9 % had deficient 25(OH)D levels, 18 % inadequate, and 73 % adequate. Deficient, or inadequate 25(OH)D levels were associated with an increased rate of MACE (HR, 1.32 [95 % CI: 1.19, 1.46], HR, 1.29 [95 % CI: 1.20, 1.40], respectively) compared to those with adequate levels. Cholecalciferol supplementation in pwMS and deficient or inadequate 25(OH)D levels did not alleviate the higher CVD rate (HR, 1.39 [95 % CI: 1.21,1.60], HR, 1.31 [95 % CI: 1.17, 1.47], respectively) in comparison to those with adequate 25(OH)D levels taking no vitamin D supplementation.

CONCLUSIONS

Deficient or inadequate 25(OH)D levels in pwMS were associated with an increased rate of MACE, which may not be mitigated by vitamin D supplementation.

How Follow-Up Period in Prospective Cohort Studies Affects Relationship Between Baseline Serum 25(OH)D Concentration and Risk of Stroke and Major Cardiovascular Events

Background/Objectives: Prospective cohort studies are useful for studying how biomolecular status affects risk of adverse health outcomes. Less well known is that the longer the follow-up time, the lower the association (or "apparent effect") due to "regression dilution". Here, we evaluate how follow-up interval from baseline to "event" affects the relationship between baseline serum 25-hydroxyvitamin D [25(OH)D] concentration and the later incidence of stroke and major cardiovascular events (MACEs). Methods: Findings for the relative risk (RR) of stroke and MACEs with respect to serum 25(OH)D concentrations at baseline from prospective cohort studies were plotted against mean follow-up time. Fifteen studies from mainly European countries and the United States were used for stroke and nine studies for MACEs. Linear regression analyses were used to study data for follow-up periods of up to 10 years and for more than 10 years. Results: For stroke, the linear regression fit for 1-10 years is RR = 0.34 + (0.065 × follow-up [years]), r = 0.84, adjusted r2 = 0.67, p < 0.001. No significant variations in association were found for studies with follow-up periods of 10-20 years. For MACEs, the linear fit for 1-8.1 years is RR = 0.61 + (0.055 × follow-up [years]), r = 0.81, adjusted r2 = 0.59, p = 0.03. Discussion: The shorter the follow-up period, the greater the apparent effect of better vitamin D status in reducing risk of stroke and MACEs. In addition, the apparent effect of higher 25(OH)D concentration found for the shortest follow-up time is more than twice as great as the estimate based on average follow-up intervals for all studies. Mechanisms have been found to explain how higher serum 25(OH)D concentrations could reduce risk of stroke and MACEs. Randomized controlled trials have not shown that vitamin D supplementation significantly reduces risk of either stroke or MACEs, probably because risk of both outcomes increases rapidly below 15 ng/mL (38 nmol/L) and it is difficult in Western developed countries to enroll enough participants with concentrations that low. Nonetheless, vitamin D's role in reducing risk of stroke and MACEs could be considered causal on the basis of an evaluation of the evidence using Hill's criteria for causality in a biological system. Conclusions: Serum 25(OH)D concentrations above 20 ng/mL are associated with significantly reduced risk of stroke and MACEs prospectively and in an apparent causal manner. Raising serum 25(OH)D concentrations to >20 ng/mL should, therefore, be recommended for everyone likely to be at risk for stroke or MACEs and indeed in the general population.

Tremendous Fidelity of Vitamin D3 in Age-related Neurological Disorders

Vitamin D3 (VD) is a secosteroid hormone and shows a pleiotropic effect in brain-related disorders where it regulates redox imbalance, inflammation, apoptosis, energy production, and growth factor synthesis. Vitamin D3's active metabolic form, 1,25-dihydroxy Vitamin D3 (1,25(OH)2D3 or calcitriol), is a known regulator of several genes involved in neuroplasticity, neuroprotection, neurotropism, and neuroinflammation. Multiple studies suggest that VD deficiency can be proposed as a risk factor for the development of several age-related neurological disorders. The evidence for low serum levels of 25-hydroxy Vitamin D3 (25(OH)D3 or calcidiol), the major circulating form of VD, is associated with an increased risk of Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), dementia, and cognitive impairment. Despite decades of evidence on low VD association with neurological disorders, the precise molecular mechanism behind its beneficial effect remains controversial. Here, we will be delving into the neurobiological importance of VD and discuss its benefits in different neuropsychiatric disorders. The focus will be on AD, PD, and HD as they share some common clinical, pathological, and epidemiological features. The central focus will be on the different attributes of VD in the aspect of its anti-oxidative, anti-inflammatory, anti-apoptotic, anti-cholinesterase activity, and psychotropic effect in different neurodegenerative diseases.

Vitamin D Supplementation in Functional Recovery of Subjects with Severe Acquired Brain Injury: A Pilot Controlled Randomized Study

Low vitamin D (VD) has been associated with poor clinical course in several neurological diseases. Supplementation has been suggested to improve outcomes. Severe acquired brain injury (sABI) subjects have low VD levels and disabling conditions requiring rehabilitation. The aim of the present study was to evaluate if VD supplementation produced a better clinical course and a better functional outcome in sABI during rehabilitation. A randomized single-blind study was performed. sABI subjects were randomized to the VD supplementation group (VDsG) (initial dose of 50.000 UI and 1.000 daily) and usual care control group (CG). Disability Rating Scale (DRS), Glasgow Outcome Scale (GOS), and Level of Cognitive Functioning (LCF) were used in assessing disability. A total of 73 subjects (42 M and 31 F; mean age 53.2 ± 15.7) were randomized: 36 (21 M and 15 F; mean age 57.52 ± 14.88) to VDsG and 37 (20 M and 17 F; mean age 48.28 ± 17.47) to CG. Both groups significantly improved after rehabilitation, and no between-group difference was observed. The mean score values for DRS, GOS, and LCF in VDsG were 18.83 ± 4.27 and 9.42 ± 5.83; 2.89 ± 0.32 and 3.78 ± 0.80; and 4.81 ± 1.70 and 7.53 ± 1.28, at admission and discharge, respectively. Likewise, mean values for DRS, GOS, and LCF in CG were 18.57 ± 4.80 and 9.84 ± 6.34; 2.84 ± 0.37 and 3.81 ± 0.94; and 4.97 ± 2.01 and 7.41 ± 1.32, respectively. VD supplementation did not improve functional outcomes in sABI during rehabilitation treatment.

Selected serum cytokines and vitamin D levels as potential prognostic markers of acute ischemic stroke

Inflammation-derived oxidative stress is postulated to contribute to neuronal damage leading to poor clinical outcomes in Acute Ischemic Stroke (AIS). We aimed to investigate the association between serum levels of selected cytokines (IL-1β, IFN-γ, IL-4), and vitamin D in ischemic stroke progression, and their accuracy in predicting AIS prognosis, among Sri Lankans. We compared 60 AIS patients admitted in 4 phases post-stroke onset (<6 h; 6-24 h; 24-48 h; 48-96 h; n = 15/phase), with 15 age- and sex-matched controls. The 30-day functional outcome (FO) was assessed using the modified Rankin Scale (mRS). Serum cytokine and vitamin D levels were quantified using sandwich ELISAs, and competitive ELISA, respectively. The CombiROC web tool established optimal prognostic biomarker combinations. Serum IL-1β and IFN-γ were elevated in all four phases following stroke onset while IL-4 was elevated exclusively in the recovery phase (48-96 h) (p<0.05). Th1 bias polarization of the Th1:Th2 cytokine (IFN-γ:IL-4) ratio occurred with AIS progression while a Th2 bias occurred during AIS recovery (p<0.05). Lower serum IL-1β and higher IL-4 levels were associated with a good FO (p<0.05), while lower Vitamin D levels were related to a poor FO (p = 0.001). The triple-biomarker panel, IL-4- IFN-γ -Vit D, accurately predicted AIS prognosis (sensitivity = 100%, specificity = 91.9%, area under the curve = 0.98). Serum immunologic mediators IFN-γ, IL-4, and vitamin D may be useful biomarkers of AIS prognosis and may serve as therapeutic targets in improving stroke outcomes. Vitamin D supplementation may improve the prognosis of AIS patients. Furthermore, binary logistic model fitted for FO indicated Th1:Th2 cytokine ratio (IFN-γ:IL-4), vitamin D status, history of stroke, and ischemic heart disease as significant predictors of AIS prognosis.

Stroke risk in multiple sclerosis: a critical appraisal of the literature

Observational studies suggest that the occurrence of stroke on multiple sclerosis (MS) patients is higher compared to the general population. MS is a heterogeneous disease that involves an interplay of genetic, environmental and immune factors. The occurrence of stroke is subject to a wide range of both modifiable and non-modifiable, short- and long-term risk factors. Both MS and stroke share common risk factors. The immune mechanisms that underlie stroke are similar to neurodegenerative diseases and are attributed to neuroinflammation. The inflammation in autoimmune diseases may, therefore, predispose to an increased risk for stroke or potentiate the effect of conventional stroke risk factors. There are, however, additional determinants that contribute to a higher risk and incidence of stroke in MS. Due to the challenges that are associated with their differential diagnosis, the objective is to present an overview of the factors that may contribute to increased susceptibility or occurrence of stroke in MSpatients by performing a review of the available to date literature. As both MS and stroke can individually detrimentally affect the quality of life of afflicted patients, the identification of factors that contribute to an increased risk for stroke in MS is crucial for the prompt implementation of preventative therapeutic measures to limit the additive burden that stroke imposes.

Association between Vitamin D and Short-Term Functional Outcomes in Acute Ischemic Stroke

Vitamin D (Vit D) affects musculoskeletal performance and central nervous system neuroprotection. We aimed to investigate the association between serum Vit D levels and short-term functional outcomes in patients with acute ischemic stroke. This study involved patients with acute ischemic stroke confirmed on brain MRI. The National Institutes of Health Stroke Scale (NIHSS) was used to assess initial stroke severity upon admission. We evaluated the functional outcomes using the Berg Balance Scale (BBS), Manual Function Test (MFT), Korean Mini-Mental State Examination (K-MMSE), Korean version of the modified Barthel Index (K-MBI) within three weeks from the onset of stroke, and modified Rankin Scale (mRS) score at discharge. Overall, 192 patients were finally included and divided into three groups: Vit D sufficient (n = 28), insufficient (n = 49), and deficient (n = 115). Multivariate analysis showed that the Vit D deficient group presented with a higher risk of initially severe stroke (p = 0.025) and poor functional outcomes on the BBS (p = 0.048), MFT (p = 0.017), K-MMSE (p = 0.001), K-MBI (p = 0.003), and mRS (p = 0.032) compared to the Vit D sufficient group. Vit D deficiency may be associated with severe initial stroke and poor short-term post-stroke functional outcomes.

Serum Vitamin D Level as a Risk Factor and Prognostic Marker for Acute Ischemic Stroke: A Case-Control Study at a Tertiary Care Centre in Northern India

Introduction Stroke is a predominant cause of death worldwide. Major risk factors for stroke in any age group are diabetes, hypertension, heart disease, smoking, and long-term alcohol abuse. It is of utmost importance to identify the risk factors for stroke to prevent recurrence. Vitamin D deficiency is identified as a risk factor for stroke. Therefore, we attempted to look for a correlation between vitamin D levels and acute ischemic stroke. Methods This observational case-control study was conducted with 150 patients (75 cases and 75 controls). On the day of admission, the National Institutes of Health Stroke Scale (NIHSS) score was calculated, and vitamin D levels were measured for each patient. The functional outcome was determined by the modified Rankin scale (mRS). Results The most common risk factors identified in this study were hypertension (61.3%), diabetes mellitus (41.3%), and smoking (37.3%). Out of 75 patients enrolled in the study, 49.4% had significant vitamin D deficiency, and 30.6% had insufficient vitamin D levels. Our study showed a significant correlation between vitamin D sufficiency in the body and the incidence of stroke (x2=3.888 and p=0.048). A significant correlation (p=0.03) was found between the NIHSS score and vitamin D levels in patients with acute ischemic stroke. Conclusion In this observational case-control study, we concluded that the increasing severity of vitamin D deficiency was associated with more deaths and poor outcomes.

Neuroimmunological Effect of Vitamin D on Neuropsychiatric Long COVID Syndrome: A Review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the coronavirus disease 2019 (COVID-19). COVID-19 is now recognized as a multiorgan disease with a broad spectrum of manifestations. A substantial proportion of individuals who have recovered from COVID-19 are experiencing persistent, prolonged, and often incapacitating sequelae, collectively referred to as long COVID. To date, definitive diagnostic criteria for long COVID diagnosis remain elusive. An emerging public health threat is neuropsychiatric long COVID, encompassing a broad range of manifestations, such as sleep disturbance, anxiety, depression, brain fog, and fatigue. Although the precise mechanisms underlying the neuropsychiatric complications of long COVID are presently not fully elucidated, neural cytolytic effects, neuroinflammation, cerebral microvascular compromise, breakdown of the blood-brain barrier (BBB), thrombosis, hypoxia, neurotransmitter dysregulation, and provoked neurodegeneration are pathophysiologically linked to long-term neuropsychiatric consequences, in addition to systemic hyperinflammation and maladaptation of the renin-angiotensin-aldosterone system. Vitamin D, a fat-soluble secosteroid, is a potent immunomodulatory hormone with potential beneficial effects on anti-inflammatory responses, neuroprotection, monoamine neurotransmission, BBB integrity, vasculometabolic functions, gut microbiota, and telomere stability in different phases of SARS-CoV-2 infection, acting through both genomic and nongenomic pathways. Here, we provide an up-to-date review of the potential mechanisms and pathophysiology of neuropsychiatric long COVID syndrome and the plausible neurological contributions of vitamin D in mitigating the effects of long COVID.

Relationships between serum levels of vitamins and papillary thyroid cancer: a single center case-control study

Background

Vitamins are involved in various human physiological and biochemical mechanisms due to their antioxidant properties and their ability to enhance the immune response. Deficiency of some serum vitamins has been reported to be associated with an increased risk of developing cancer, including thyroid cancer. However, medical literature dealing with cholecalciferol supplementation was not able to show the potential of this intervention in cancer prevention. The aim of this paper is to highlight the association between lower serum vitamins levels and papillary thyroid cancer occurrence.

Methods

This case-control study was conducted between September 2018 and October 2019. Cases were defined as patients with histologically diagnosed papillary thyroid cancer who underwent thyroidectomy were retrospectively recruited and serum levels of various vitamins were assessed by examining their relationships with clinical, pathological and molecular data (n=51). Controls matched on sex and thyroid surgery were randomly selected from the same population (n=49).

Results

In this study, serum concentrations of vitamins A and E in neoplastic patients were significantly lower than in controls (1.40 vs. 1.78, P<0.003 and 23.9 vs. 29.1, P<0.003, respectively). Serum concentrations of vitamin D and methylmalonic acid were borderline significantly low (15.6 vs. 17.9, P=0.06 and 100.3 vs. 110.4, P=0.055, respectively), while homocysteine was statistically similar in the two groups. Furthermore, serum vitamin levels were compared with the pathological characteristics of cancer patients, and vitamin D concentrations were significantly lower in BRAF-positive than in BRAF-negative neoplastic patients (8.2 vs. 16.0, P=0.021). On the other hand, no significant differences were observed in the correlation between serum levels of vitamins and other pathological characteristics, in particular with regard to lymph node metastases.

Conclusions

In conclusion, albeit with the analysis of a limited sample, this study highlighted the phenomenon that deficiencies in vitamins A and E can be associated with a higher frequency of occurrence of papillary thyroid cancer.

Vitamin D in atherosclerosis and cardiovascular events

Both experimental and clinical findings linking vitamin D to cardiovascular (CV) risk have prompted consideration of its supplementation to improve overall health. Yet several meta-analyses do not provide support for the clinical effectiveness of this strategy. Meanwhile, the understanding of the roles of vitamin D in the pathophysiology of CV diseases has evolved. Specifically, recent work has revealed some non-classical pleiotropic effects of vitamin D, increasing the complexity of vitamin D signalling. Within particular microenvironments (e.g. dysfunctional adipose tissue and atherosclerotic plaque), vitamin D can act locally at cellular level through intracrine/autocrine/paracrine feedforward and feedback circuits. Within atherosclerotic tissues, 'local' vitamin D levels may influence relevant systemic consequences independently of its circulating pool. Moreover, vitamin D links closely to other signalling pathways of CV relevance including those driving cellular senescence, ageing, and age-related diseases-among them CV conditions. This review updates knowledge on vitamin D biology aiming to clarify the widening gap between experimental and clinical evidence. It highlights the potential reverse causation confounding correlation between vitamin D status and CV health, and the need to consider novel pathophysiological concepts in the design of future clinical trials that explore the effects of vitamin D on atherosclerosis and risk of CV events.

Vitamin D levels and oral health in stroke patients during inpatient rehabilitation

BACKGROUND

Stroke is a severe that restricts the individual's functions, effects the oral health.

OBJECTIVES

The aim of this study was to investigate the relationship between oral health and vitamin D levels in stroke patients in rehabilitation units.

METHODS

Participants with stroke, and age- and sex-matched healthy controls were recruited for the study. Oral Health Impact Scale-14 (OHIP-14), Decayed, Missing, Filled Teeth (DMFT) Index, Community Periodontal Index of Treatment Needs (CPITN), Gingival Index (GI) and Plaque Index (PI) were assessed for all participants. Barthel Index (BI), Brunnstrom Recovery Scale (BRS) and Modified Ashworth Scale (MAS) assessed for the stroke patients. Vitamin D levels of each participant were recorded.

RESULTS

The stroke patients' DMFT index and OHIP-14 values were higher than those of the healthy controls (p < .05). However, no significant differences were observed in terms of CPTIN, PI, or GI scores (p > .05). No statistically significant difference was determined in the DMFT index, OHIP-14 scores, Community Periodontal Index of Treatment Needs (CPITN), PI (Plaque Index) and GI (Gingival Index) scores according to vitamin D levels among the stroke patients (p > .05). Stroke patients' functional scores (BRS, MAS and BI), vitamin D levels and oral health status (OHIP-14, DMFT, CPITN, PI and GI) were subjected to correlation analysis. This revealed significant negative correlation between BRS (arm, hand and leg), and BI and OHIP-14 scores (p < .05).

CONCLUSION

Although the DMFT index and oral health-related quality of life were adversely affected in stroke patients, no relationship was found between vitamin D and oral health status.

Microglia/macrophages require vitamin D signaling to restrain neuroinflammation and brain injury in a murine ischemic stroke model

Vitamin D deficiency is associated with worse clinical outcomes after ischemic stroke; nevertheless, the pathophysiological mechanisms remain largely unexplored. In this study, we characterized the molecular mechanisms of how vitamin D signaling modulated stroke progression in male mouse ischemia-reperfusion stroke models. We found that vitamin D receptor (VDR) exhibited a predominant upregulation in peri-infarct microglia/macrophages following cerebral ischemia. Conditional Vdr inactivation in microglia/macrophages markedly augmented infarct volumes and neurological deficits. VDR-deficient microglia/macrophages exhibited a more primed proinflammatory phenotype with substantial secretion of TNF-α and IFN-γ. These inflammatory cytokines further enhanced CXCL10 release from endothelial cells and blood-brain barrier disruption, and ultimately infiltration of peripheral T lymphocytes. Notably, blocking TNF-α and IFN-γ significantly ameliorated stroke phenotypes in Vdr conditional knockout mice. Collectively, VDR signaling in microglia/macrophages plays a crucial role in restraining ischemia-elicited neuroinflammation and stroke progression. Our findings delineate a novel mechanism underlying the association between vitamin D deficiency and poor stroke outcomes, and underline the significance of maintaining a functional vitamin D signaling in the management of acute ischemic stroke.

Calcitriol modulate post-ischemic TLR signaling pathway in ischemic stroke patients

BACKGROUND

Neuroinflammation is a significant contributor to post-ischemic neuronal death after stroke, and Toll-Like Receptors (TLRs) are one of the essential mediators in many inflammatory pathways. TLRs activate the nuclear factor kappa β (NF-kβ), which promotes the expression of various pro-inflammatory genes such as interleukin (IL-1β) and IL-6. 1,25(OH)2D3, also known as calcitriol, is an active form of vitamin D3 that acts as a neurosteroid compound with anti-inflammatory properties. This study aimed to determine the modulatory effects of calcitriol hormone on post-ischemic immunity response.

METHODS

Neurological tests and conventional blood factors were evaluated in patients with stroke symptoms upon arrival (n = 38) to confirm the stroke. A blood sample was taken from each stroke patient immediately upon admission and again after 24 h. The experimental group was given 10 μg calcitriol orally. The gene expression levels of TLR4, TLR2, NF-kβ, IL-1β, and IL-6 pro-inflammatory factors were measured using real-time PCR. The protein expression of TLR4 and NF-kβ markers was assessed using the flow cytometry technique.

RESULTS

TLR4, NF-kβ, and pro-inflammatory factors IL-1β and IL-6 expression increased significantly after an ischemic stroke, and calcitriol could modulate the TLR4/NF-kβ signaling pathway 24 h after ischemia.

CONCLUSIONS

Calcitriol may be considered a protective reagent after ischemia by reducing the TLR4/NF-kB activation cascade and probably plays a beneficial role in reducing and improving ischemic stroke patients' symptoms.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials identifier: IRCT2017012532174N1.

Serum 25-hydroxyvitamin D is associated with stroke history in a reverse J-shape

Background

25-hydroxyvitamin D [25(OH)D], the major form of vitamin D in the body, has a non-linear association with stroke risk. However, the association is not fully understood. The specific shape of the association and the ideal value of 25(OH)D related to minimum risk of stroke remain unclear.

Aim

We conducted the study to establish the correlation between circulating 25(OH)D and stroke history and determine the ideal value of 25(OH)D in relation to the lowest stroke prevalence.

Methods

Data from the National Health and Nutrition Examination Survey (NHANES) were used for analyzes. We used multivariate logistic regression analysis with fitted smooth curves to explore the relationship between 25(OH)D and self-reported stroke history. Subsequently, 40,632 participants were enrolled in the study.

Results

A reverse J-shaped association between 25(OH)D and stroke history was determined, where the lowest stroke prevalence for the 25(OH)D level was about 60 nmol/L. After adjusting for confounding factors, prevalence of stroke showed an increasing trend below and above the middle quintile (53.2-65.4 nmol/L) of 25(OH)D. Participants with 25(OH)D levels in the lowest quintile (≤ 39.3 nmol/L) had a 38% increased prevalence of stroke (OR 1.38, 95 %CI 1.12-1.70), while those in the higher level range of 25(OH)D (65.5-80.8 nmol/L) had a 27% higher stroke prevalence (OR 1.27, 95 %CI 1.03-1.57).

Conclusion

Using data from a large, cross-sectional cohort program, we found that circulating 25(OH)D was related to stroke history in a reverse J-shaped manner. Given how the causal relationship between circulating 25(OH)D and history of stroke has not been established, more high-quality evidence based on the reverse J-shaped feature is needed to elucidate the link between vitamin D and stroke risk, and the effect of vitamin D supplements on stroke prevention.

The association of 25 (OH) D3 serum level with ischemic cerebrovascular accident risk, severity and outcome in Iranian population

OBJECTIVES

The role of combined presence of vitamin D deficiency and other risk factors of stroke in ischemic cerebrovascular accident (CVA) development in Iranian adults has been unclear, so far. The association of vitamin D status at admission with ischemic CVA severity and outcome in this community is not yet well elucidated. This study aimed to clarify these ambiguities.

METHODS

In a cross-sectional study 104 hospitalized ischemic CVA patients and 104 healthy controls participated. The serum level of 25 (OH) D3 and baseline biochemical parameters were measured in ischemic patients within the first 24 h of admission, as well as healthy controls. The severity of CVA and clinical outcome were assessed using National Institutes Health Stroke Scale and Modified Rankin Scale, respectively. Data were analyzed using the Chi-square test, independent t-test, and multiple logistic regression.

RESULTS

There was a significant difference between patients and controls regarding the presence of vitamin D3 deficiency, hypertension, smoking, and baseline level of LDL and FBS. Vitamin D3 deficiency boosted the risk of ischemic in males and those having family history of CVA. A low serum level of 25 (OH) D3 was associated with more severity and poor outcome of CVA. The CVA severity, vitamin D3 deficiency, and hypertension were predictors of poor outcome.

CONCLUSIONS

The study highlights the increased risk of ischemia in Iranians by cooccurrence of vitamin D3 deficiency and other risk factors of CVA. Clinical significance of vitamin D3 deficiency control may be suggested in those at risk of CVA and functional poor outcomes.

Vitamin D Promotes Remyelination by Suppressing c-Myc and Inducing Oligodendrocyte Precursor Cell Differentiation after Traumatic Spinal Cord Injury

Demyelination due to oligodendrocytes loss occurs after traumatic spinal cord injury (TSCI). Several studies have suggested the therapeutic potential of vitamin D (VitD) in demyelinating diseases. However, experimental evidence in the context of TSCI is limited, particularly in the presence of prior VitD-deficiency. In the present study, a contusion and a transection TSCI rat model were used, representing mild and severe injury, respectively. Motor recovery was assessed in rats with normal VitD level or with VitD-deficiency after 8 weeks' treatment post-TSCI (Cholecalciferol, 500 IU/kg/day). The impact on myelin integrity was examined by transmission electron microscopy and studied in vitro using primary culture of oligodendrocytes. We found that VitD treatment post-TSCI effectively improved hindlimb movement in rats with normal VitD level irrespective of injury severity. However, cord-transected rats with prior deficiency did not seem to benefit from VitD supplementation. Our data further suggested that having sufficient VitD was essential for persevering myelin integrity after injury. VitD rescued oligodendrocytes from apoptotic cell death in vitro and enhanced their myelinating ability towards dorsal root axons. Enhanced myelination was mediated by increased oligodendrocyte precursor cells (OPCs) differentiation into oligodendrocytes in concert with c-Myc downregulation and suppressed OPCs proliferation. Our study provides novel insights into the functioning of VitD as a regulator of OPCs differentiation as well as strong preclinical evidence supporting future clinical testing of VitD for TSCI.

Persistent or new symptoms 1 year after a single high dose of vitamin D3 in patients with moderate to severe COVID-19

Purpose

The aim of this study was to investigate the reported persistent or new symptoms 1 year after a single dose of 200,000 IU of vitamin D₃ and hospitalization in patients with moderate to severe COVID-19.

Methods

This is a post-hoc, exploratory analysis from a multicenter, double-blind, placebo-controlled, randomized clinical trial from two hospitals in São Paulo, Brazil, registered in ClinicalTrials.gov, NCT04449718. Discharged patients were followed for up to 1 year and evaluated by telephone interviews at 6 and 12 months. The primary and secondary outcomes were previously published. These post-hoc exploratory secondary outcomes are the persistent or new symptoms and quality of life (QoL) at the post-viral stage of COVID-19. Generalized estimating equations (GEE) for repeated measures with Bonferroni’s adjustment were used for testing outcomes.

Results

Between 2 June and 27 August 2020, we randomized 240 patients of which 144 were included in this study [the vitamin D₃ (n = 71) or placebo (n = 73) group]. The mean (SD) age was 54.3 (13.1) years, and body mass index (BMI) was 32.4 (6.5) kg/m². Fever demonstrated a significant main effect of time (P < 0.001) with a reduction from baseline to 6 (52–0) and 12 months (52–0). No significant differences between groups were observed for fever, cough, fatigue, fever, myalgia, joint pain, runny nose, nasal congestion, sore throat, hypertension, diabetes, cardiovascular disease, rheumatic disease, asthma, chronic obstructive pulmonary, chronic kidney disease, QoL, and new or persistent symptoms up to 1-year of follow-up.

Conclusion

The findings do not support the use of 200,000 IU of vitamin D₃ compared to placebo for the management of persistence or new symptoms, and QoL reported by moderate to severe patients after hospitalization for COVID-19.

Vitamin D supplementation and risk of stroke: A meta-analysis of randomized controlled trials

Background

Previous observational studies have supported the hypothesis that vitamin D supplementation protects against stroke. However, several current intervention studies contradict this observation. Therefore, we conducted a meta-analysis to investigate further the association between vitamin D supplementation and the risk of stroke.

Methods

This meta-analysis was conducted in accordance with the PRISMA statement and included all the randomized controlled trials (RCTs) that analyzed the relationship between vitamin D supplementation and the risk of stroke. A literature search strategy was established, and the following Medical Search Terms (MeSH) were used: “vitamin D,” “Calcitriol,” “Calcifediol,” “Cholecalciferol,” “25-Hydroxyvitamin D 2,” “ergocalciferols,” “stroke,” and stroke-derived terms. We searched for articles published before January 2022 in several databases, namely, PubMed, Web of Science, EMBASE, and The Cochrane Library. We also reviewed references included in relevant published meta-analyses and searched the http://www.ClinicalTrials.gov website for additional RCTs. The Q test and I2 were utilized to assess the degree of heterogeneity among the studies. Review Manager 5.3 and STATA16.0 software programs were used to assess the literature quality and perform statistical analyses.

Results

In total, twenty-four RCTs (86,202 participants) were included. There was no statistical heterogeneity among the RCTs (I2 = 0.0%, P = 0.94) included in this meta-analysis. We determined that vitamin D supplementation was not associated with a reduced risk of stroke compared with the placebo (RR = 1.02, 95% CI: 0.93–1.13, P = 0.65). In total, 10 studies only included women, and 14 studies included women and men among the 24 RCTs. Therefore, we performed a subgroup analysis based on sex. After the subgroup analysis, the effect remained statistically insignificant (mixed-sex group: RR = 1.06, 95% CI: 0.93–1.22, P = 0.37, women group: RR = 0.98, 95% CI: 0.86–1.13, P = 0.80). The results were generally comparable, based on age, body mass index (BMI), follow-up period, baseline 25-hydroxyvitamin D (25(OH)D) levels, the designated endpoint, latitude, vitamin D dosage, type of vitamin D administered, and an absence or presence of concurrent calcium supplementation (P &gt; 0.05).

Conclusion

Our study revealed that additional vitamin D supplementation did not reduce the risk of stroke. Therefore, additional RCTs of similar design should not be encouraged to assess any association between vitamin D supplementation and reduced stroke risk.

The Role of Vitamin D in Stroke Prevention and the Effects of Its Supplementation for Post-Stroke Rehabilitation: A Narrative Review

Hypovitaminosis D is a serious public health problem, representing an independent factor in mortality among the general population. Vitamin D deficiency may affect up to one billion people worldwide. Recently, the potential association between vitamin D levels and stroke has gained increasing attention. Many studies suggest that maintaining normal serum vitamin D levels is associated with improvement of the cardiovascular system and a reduction in stroke risk. As a neurosteroid, vitamin D influences brain development and function and immunomodulation and affects brain neuroplasticity. It supports many processes that maintain homeostasis in the body. As stroke is the second most common cause of death worldwide, more studies are needed to confirm the positive effects of vitamin D supplementation, its dosage at different stages of the disease, method of determination, and effect on stroke onset and recovery. Many studies on stroke survivors indicate that serum vitamin D levels only offer insignificant benefits and are not beneficial to recovery. This review article aims to highlight recent publications that have examined the potential of vitamin D supplementation to improve rehabilitation outcomes in stroke survivors. Particular attention has been paid to stroke prevention.

Association of vitamin D status with COVID-19 and its severity : Vitamin D and COVID-19: a narrative review

Vitamin D is associated with biological activities of the innate and adaptive immune systems, as well as inflammation. In observational studies, an inverse relationship has been found between serum 25-hydroxyvitamin D (25(OH)D) concentrations and the risk or severity of coronavirus disease 2019 (COVID-19). Several mechanisms have been proposed for the role of vitamin D in COVID-19, including modulation of immune and inflammatory responses, regulation of the renin-angiotensin-aldosterone system, and involvement in glucose metabolism and cardiovascular system. Low 25(OH)D concentrations might predispose patients with COVID-19 to severe outcomes not only via the associated hyperinflammatory syndrome but also by worsening preexisting impaired glucose metabolism and cardiovascular diseases. Some randomized controlled trials have shown that vitamin D supplementation is beneficial for reducing severe acute respiratory syndrome coronavirus 2 RNA positivity but not for reducing intensive care unit admission or all-cause mortality in patients with moderate-to-severe COVID-19. Current evidence suggests that taking a vitamin D supplement to maintain a serum concentration of 25(OH)D of at least 30 ng/mL (preferred range 40-60 ng/mL), can help reduce the risk of COVID-19 and its severe outcomes, including mortality. Although further well designed studies are warranted, it is prudent to recommend vitamin D supplements to people with vitamin D deficiency/insufficiency during the COVID-19 pandemic according to international guidelines.

Relationship between Serum 25-Hydroxyvitamin D Level and Risk of Recurrent Stroke

Evidence for the association between vitamin D and risk of recurrent stroke remains sparse and limited. We aimed to assess the relationship between serum circulating 25-hydroxyvitamin D (25(OH)D) level and risk of recurrent stroke in patients with a stroke history, and to identify the optimal 25(OH)D level in relation to lowest recurrent stroke risk. Data from the nationwide prospective United Kingdom Biobank were used for analyses. Primary outcome was time to first stroke recurrence requiring a hospital visit during follow-up. We used Cox proportional hazards regression model with restricted cubic splines to explore 25(OH)D level in relation to recurrent stroke. The dose-response relationship between 25(OH)D and recurrent stroke risk was also estimated, taking the level of 10 nmol/L as reference. A total of 6824 participants (mean age: 60.6 years, 40.8% females) with a baseline stroke were included for analyses. There were 388 (5.7%) recurrent stroke events documented during a mean follow-up of 7.6 years. Using Cox proportional hazards regression model with restricted cubic splines, a quasi J-shaped relationship between 25(OH)D and risk of recurrent stroke was found, where the lowest recurrent stroke risk lay at the 25(OH)D level of approximate 60 nmol/L. When compared with 10 nmol/L, a 25(OH)D level of 60 nmol/L was related with a 48% reduction in the recurrent stroke risk (hazard ratio = 0.52, 95% confidence interval: 0.33-0.83). Based on data from a large-scale prospective cohort, we found a quasi J-shaped relationship between 25(OH)D and risk of recurrent stroke in patients with a stroke history. Given a lack of exploring the cause-effect relationship in this observational study, more high-quality evidence is needed to further clarify the vitamin D status in relation to recurrent stroke risk.

The Evaluation of the Neuroprotective Effect of a Single High-Dose Vitamin D3 in Patients with Moderate Ischemic Stroke

INTRODUCTION

Vitamin D insufficiency is highly prevalent and is a negative predictor for survival in ischemic stroke patients. We evaluated the effect of a high dose of vitamin D3 on the Neuron-Specific Enolase (NSE) level, National Institute of Health Stroke Scale (NIHSS), and Barthel Index (BI) scoring system in moderate ischemic stroke patients.

METHODS

This prospective, double-blind, randomized clinical trial (RCT) study was conducted from April 2020 to March 2021. Patients with moderate ischemic stroke (NIHSS 5 to 15) who had vitamin D deficiency (serum 25-OH vitamin D ≤30 ng/mL) were recruited and randomized into intervention and control groups. Subjects in the intervention group received a single dose, intramuscular (IM) injection of 600000 international unit (IU) vitamin D3, in addition to the standard treatment. NSE level and NIHSS were evaluated at baseline and 48 hours after the intervention. The BI was monitored three months after discharge.

RESULTS

During the study period, 570 patients were assessed; finally, forty-one patients completed the study. Except for the age which was higher in the control group (p = 0.04), there were no statistically significant differences in other baseline characteristics between the two groups. After 48 hours, the NIHSS score was significantly lower in the intervention group (median 8 vs. 6.5, p = 0.008 in the control and intervention groups, respectively), but there was no significant difference in the NSE level (p = 0.80). Three months after discharge, the BI was significantly higher in the intervention group (median 8 vs. 9, p = 0.03 in the control and intervention groups, respectively).

CONCLUSIONS

Administration of a single 600000 IU of vitamin D3 could have neuroprotective effects in patients with moderate ischemic stroke, according to its significantly positive effects on functional clinical outcomes (NIHSS and BI), but this effect on the biomarker related to neural damage (NSE) was not significant.

Vitamin D Deficiency in Patients with Diabetes in French Guiana: Epidemiology and Relation with Microvascular and Macrovascular Complications

Vitamin D (VD) insufficiency is common among patients with diabetes in French Guiana. The study aimed to evaluate the prevalence of VD deficiency in the different type of diabetes encountered and to analyze the relationship between VD deficiency and diabetes complications. Methods: An observational study was conducted between May 2019 and May 2020 in French Guiana, based on data from the CODIAM study (Diabetes Cohort in French Amazonia), describing the characteristics of patients with diabetes mellitus. Among 600 patients enrolled with diabetes, 361 had an available VD assay. Results: The mean 25(OH)VD (hydroxycalciferol) level was 27.9 ng/mL. The level of VD was inversely proportional to the HbA1c (glycated hemoglobin) level. Patients with angina pectoris had a greater proportion of deficiencies VD < 20 ng/mL than those without angina. By contrast, patients with retinopathy had higher vitamin D concentrations than those without retinopathy. There was no association between vitamin D and arteriopathy, stroke, nephropathy and polyneuropathy. VD deficiency was more frequent in women, and in patients with a high school education. Conclusion: The prevalence of VD deficiency was high in patients with diabetes in French Guiana, emphasizing the importance of VD supplementation.

Nutritional Supplementation of Naturally Occurring Vitamin D to Improve Hemorrhagic Stroke Outcomes

Vitamin D deficiency, if left untreated, is associated with bone disorders, cardiovascular damage, and an increased risk of ischemic stroke. While there are various nutritional options for the natural intake of vitamin D, we hope to elucidate the potential mechanisms dietary vitamin D may play in hemorrhagic stroke pathology. This scoping review outlines findings from studies relevant to the biochemical activity of vitamin D, the impact of vitamin D deficiency on hemorrhagic stroke outcomes, and the potential benefit of nutritional vitamin D on hemorrhagic stroke outcomes. Here, we analyze the relevant factors that can lead to vitamin D deficiency, and subsequently, a higher risk of hemorrhagic stroke incidence with worsened subsequent outcomes. The neuroprotective mechanisms through which vitamin D works to attenuate hemorrhagic stroke onset and post-stroke outcomes have not yet been thoroughly examined. However, researchers have proposed several potential protective mechanisms, including reduction of blood brain barrier disturbance by inhibiting the production of reactive oxygen species, mitigation of inflammation through a reduction of levels of proinflammatory cytokines, and prevention of cerebral vasospasm and delayed cerebral ischemia following subarachnoid hemorrhage and intracerebral hemorrhage. While more research is needed and there are limitations to vitamin D supplementation, vitamin D as a whole may play a significant role in the dynamics of hemorrhagic stroke. Further research should focus on expanding our understanding of the neuroprotective capacity and mechanisms of vitamin D, as well as how vitamin D supplementation could serve as an effective course of treatment of hemorrhagic strokes.

Benefits of vitamin D supplementation to attenuate TBI secondary injury?

Vitamin D supplementation has been shown to improve outcomes for patients suffering from a variety of illnesses such as stroke and cancer. Vitamin D deficiencies have been associated with longer hospital stays, greater severity of symptoms, and death in some complex cases. Due to vitamin D’s burgeoning role in improving patient outcomes, a new sector of research is focusing on the lesser-known implications of vitamin D on health. Traumatic brain injury (TBI) affects approximately 69 million people worldwide per year. Here, we summarize the current scientific understanding of vitamin D dynamics with TBI to elucidate a potential way to lessen the cascade of secondary damage after an initial insult, with the goal of improving overall patient outcomes. Because vitamin D supplementation has been correlated with better outcomes in other pathologies involving immune and inflammatory molecules, it is important to study the potential effect of vitamin D deficiency (VDD) and supplementation on TBI outcomes. Research on vitamin D supplementation in TBI remains in the preliminary stages. There is still much to learn about vitamin D deficiency, dosage, variants of supplementary forms, mechanisms, and its role in TBI.