Low Serum Levels of 25-Hydroxyvitamin D Are Associated with Stroke Recurrence and Poor Functional Outcomes in Patients with Ischemic Stroke

Causal effect of serum 25 hydroxyvitamin D concentration on cardioembolic stroke: Evidence from two-sample Mendelian randomization

BACKGROUND AND AIMS

The putative association between serum 25-hydroxyvitamin D concentration [25(OH)D] and the risk of cardioembolic stroke (CES) has been examined in observational studies, which indicate controversial findings. We performed Mendelian randomization (MR) analysis to determine the causal relationship of serum 25(OH)D with the risk of CES.

METHODS AND RESULTS

The summary statistics dataset on the genetic variants related to 25(OH)D was used from the published GWAS of European descent participants in the UK Biobank, including 417,580 subjects, yielding 143 independent loci in 112 1-Mb regions. GWAS summary data of CES was obtained from GIGASTROKE Consortium, which included European individuals (10,804 cases, 1,234,808 controls). Our results unveiled a causal relationship between 25(OH)D and CES using IVW [OR = 0.82, 95% CI: 0.67-0.98, p = 0.037]. Horizontal pleiotropy was not seen [MR-Egger intercept = 0.001; p = 0.792], suggesting an absence of horizontal pleiotropy. Cochrane's Q [Q = 78.71, p-value = 0.924], Rucker's Q [Q = 78.64, p-value = 0.913], and I2 = 0.0% (95% CI: 0.0%, 24.6%) statistic suggested no heterogeneity. This result remained consistent using different MR methods and sensitivity analyses, including Maximum likelihood [OR = 0.82, 95%CI: 0.67-0.98, p-value = 0.036], Constrained maximum likelihood [OR = 0.76, 95%CI: 0.64-0.90, p-value = 0.002], Debiased inverse-variance weighted [OR = 0.82, 95%CI: 0.68-0.99, p-value = 0.002], MR-PRESSO [OR = 0.82, 95%CI 0.77-0.87, p-value = 0.022], RAPS [OR = 0.82, 95%CI 0.67-0.98, p-value = 0.038], MR-Lasso [OR = 0.82, 95%CI 0.68-0.99, p-value = 0.037].

CONCLUSION

Our MR analysis provides suggestive evidence that increased 25(OH)D levels may play a protective role in the development of cardioembolic stroke. Determining the role of 25(OH)D in stroke subtypes has important clinical and public health implications.

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.

A systematic review examining the effect of vitamin D supplementation on functional outcomes post-stroke

OBJECTIVE

The objective of this systematic review was to explore the effect of vitamin D supplementation on functional outcomes (motor function, mobility, activities of daily living and stroke impairment) among individuals post-stroke (PROSPERO CRD42022296462).

DATA SOURCES

MEDLINE, PsycINFO, EMBASE, and CINAHL were searched for all articles published up to March 5, 2023.

METHODS

Only interventional studies assessing vitamin D supplementation compared to placebo or usual care in adult stroke patients were selected. After duplicate removal, 2912 studies were screened by two independent reviewers. A total of 43 studies underwent full text review; 10 studies met inclusion criteria (8 randomized controlled trials and 2 non-randomized studies of intervention). Data were extracted by two independent reviewers using Covidence software. Motor function (Brunnstrom Recovery Stage, Berg Balance Score), mobility (Functional Ambulation Category), activities of daily living (Barthel Index, Functional Independence Measure) and stroke impairment (modified Rankin Scale, National Institutes for Health Stroke Severity, Scandinavian Stroke Severity) were the outcome measures of interest reported in the included studies.

RESULTS

In total, 691 patients were studied for which 11 of 13 outcome measures showed improvement with vitamin D supplementation.

CONCLUSIONS

The majority of studies showed a statistical improvement in motor function, mobility, and stroke impairment with vitamin D supplementation; however, the evidence did not support an improvement in activities of daily living with treatment. Despite this, there may not be clinical significance. Strong, methodologically sound, randomized controlled trials are required to verify these findings.

Effect of High-dose Vitamin D on IL-1β Blood Level in Patients with Moderate Stroke: A Randomized Clinical Trial

Background

Vitamin D has neuroprotective and anti-inflammatory effects in stroke patients, but its effect on pro-inflammatory and inflammatory cytokines, especially IL-1, has been investigated in a few trials.

Objectives

This study aimed to determine the effect of prescribing a high dose of vitamin D on the anti-inflammatory parameters, short-term and long-term prognosis of patients with ischemic stroke.

Methods

This randomized clinical trial was performed on 42 patients randomly divided into two equal groups of 21 in Imam Hussein Hospital. The patients were allocated through block randomization methods to receive 300,000 units of vitamin D (intramuscularly) or not receive it as a control group. Age, gender, and clinical and laboratory information were recorded. The stroke severity was calculated according to the National Institute of Health Stroke Scale (NIHSS) at the beginning of hospitalization and upon hospital discharge. The 3-month prognosis of the patients was recorded according to the Barthel criteria three months after the stroke. Vitamin D3 levels were recorded before and after injection, while the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were assessed on the first day and for 7 consecutive days after hospitalization. All statistical analyses were performed using STATA version 14. A P-value < 0.05 was considered significant.

Results

The mean age of the patients was 61.45 ± 4.74 years. There were 18 female (42.86%) and 24 male patients (57.14%). In the vitamin D group, the mean IL-1 decreased compared to before the intervention (-23.60 ± 103.83), but this decrease was not statistically significant (P = 0.070). In addition, the changes in IL-1 after the intervention were statistically different between the two groups (mean difference of -23.60 ± 103.83 in the vitamin D group vs. 15.96 ± 9.64 in the control group). The mean IL-6 decreased in both groups after the intervention compared to before, although these changes were not statistically significant (P > 0.05). In the group receiving vitamin D compared to the control group, the mean NLR decreased by about 2 units, the PLR decreased by about 10 units, and the NIHSS score decreased by about one unit during the study. However, these changes were not statistically significant (P > 0.05).

Conclusions

A high dose of vitamin D can improve the NIHSS score and decrease IL-1 and IL-6, although these changes were not statistically significant. The mean NLR and PLR decreased after using high-dose vitamin D.

25-Hydroxy-Vitamin D and Risk of Recurrent Stroke: A Dose Response Meta-Analysis

Stroke recurrence significantly improves the prognosis quoad vitam et valetudinem of patients with a first ischemic or haemorrhagic stroke. Other than in bone and skeletal metabolism, vitamin D is involved in the pathogenesis of cardiovascular disorders. This meta-analysis was performed to evaluate the relationship between 25OH-vitamin D [25(OH)D] levels at the first stroke and the stroke recurrence. To 31 July 2022, four prospective studies were identified. The potential non-linear relationship was evaluated by modelling 25(OH)D, using restricted cubic splines of 25(OH)D distribution. The pooled estimated risk (and 95% CI) of the recurrence of stroke, comparing the highest and the lowest levels, was assessed using a random-effect model. A non-linear association was found by dose-response analysis. This study found that 25(OH)D levels at the first stroke ≥9.3 ng/mL were associated with a lower risk of stroke recurrence, compared with 25(OH)D levels ≤8.5 ng/mL. In the pooled analysis, higher 25(OH)D levels at the first stroke significantly reduce the risk of stroke recurrence, with a significant heterogeneity among studies. In conclusion, 25(OH)D levels ≤8.5 ng/mL at the first stroke are significantly associated with a higher risk of recurrent stroke.

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.

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.

Circulating 25-hydroxy-vitamin D and the risk of cardiovascular diseases. Systematic review and meta-analysis of prospective cohort studies

AIMS

Circulating vitamin D is linked with the risk of cardiovascular disease (CVD). A meta-analysis has yet to explicitly explore correlation between vitamin D and the risk of CVD incidence and recurrent CVD. This meta-analysis examines the association between 25-hydroxy-vitamin D (25(OH)D) and the risk of CVD incidence (fatal, non-fatal, fatal and non-fatal combined events) and the risk of recurrent CVD (fatal, recurrent, and fatal and recurrent combined events). PROSPERO registration-CRD42021251483.

DATA SYNTHESIS

A total of 79 studies (46 713 CVD cases in 1 397 831 participants) were included in the meta-analysis, of which 61 studies examined the risk of CVD incidence events, and 18 studies examined risk of recurrent CVD events. The risk of CVD incidence events (RR = 1.34, 95% CI: 1.26-1.43, p < 0.001) and recurrent CVD events (RR = 1.86, 95% CI: 1.46-2.36, p < 0.001) was higher in the lowest than the highest category of circulating 25(OH)D. Dose-response analysis reported a linear association for every 10 ng/ml increment of 25(OH)D and non-fatal CVD incidence events (RR = 0.94; 95% CI = 0.89-0.98, p = 0.005), lower fatal recurrent CVD events (RR = 0.45; 95% CI = 0.32-0.62, p < 0.001) and lower combined recurrent CVD events (RR = 0.80; 95% CI = 0.65-0.97, p = 0.023). A non-linear association was observed between higher 25(OH)D and lower fatal CVD incidence events (P-nonlinear<0.001), lower combined CVD incidence events (P-nonlinear = 0.001), and lower non-fatal recurrent CVD events (P-nonlinear = 0.044).

CONCLUSIONS

The lowest category of circulating 25(OH)D was associated with a higher risk of CVD incidence events and recurrent CVD events.

Mendelian Randomization Focused Analysis of Vitamin D on the Secondary Prevention of Ischemic Stroke

BACKGROUND AND PURPOSE

Experimental studies showed vitamin D (Vit-D) could promote vascular regeneration and repair. Prior randomized studies had focused mainly on primary prevention. Whether Vit-D protects against ischemic stroke and myocardial infarction recurrence among subjects with prior ischemic insults was unknown. Here, we dissected through Mendelian randomization any effect of Vit-D on the secondary prevention of recurrent ischemic stroke and myocardial infarction.

METHODS

Based on a genetic risk score for Vit-D constructed from a derivation cohort sample (n=5331, 45% Vit-D deficient, 89% genotyped) via high-throughput exome-chip screening of 12 prior genome-wide association study-identified genetic variants of Vit-D mechanistic pathways (rs2060793, rs4588, and rs7041; F statistic, 73; P<0.001), we performed a focused analysis on prospective recurrence of myocardial infarction (MI) and ischemic stroke in an independent subsample with established ischemic disease (n=441, all with prior first ischemic event; follow-up duration, 41.6±14.3 years) under a 2-sample, individual-data, prospective Mendelian randomization approach.

RESULTS

In the ischemic disease subsample, 11.1% (n=49/441) had developed recurrent ischemic stroke or MI and 13.3% (n=58/441) had developed recurrent or de novo ischemic stroke/MI. Kaplan-Meier analyses showed that genetic risk score predicted improved event-free survival from recurrent ischemic stroke or MI (log-rank, 13.0; P=0.001). Cox regression revealed that genetic risk score independently predicted reduced risk of recurrent ischemic stroke or MI combined (hazards ratio, 0.62 [95% CI, 0.48-0.81]; P<0.001), after adjusted for potential confounders. Mendelian randomization supported that Vit-D is causally protective against the primary end points of recurrent ischemic stroke or MI (Wald estimate: odds ratio, 0.55 [95% CI, 0.35-0.81]) and any recurrent or de novo ischemic stroke/MI (odds ratio, 0.64 [95% CI, 0.42-0.91]) and recurrent MI alone (odds ratio, 0.52 [95% CI, 0.30-0.81]).

CONCLUSIONS

Genetically predicted lowering in Vit-D level is causal for the recurrence of ischemic vascular events in persons with prior ischemic stroke or MI.

Role of Vitamin D in Cerebrovascular Disease

Introduction

Vitamin D deficiency is now a well-recognized public health problem affecting almost every second person throughout the world. Recent evidence from many population-based studies has indicated that a poor vitamin D status is a predictor of future strokes.

Materials and Methods

We reviewed recent studies on 25-hydroxyvitamin D [25(OH)D] and symptomatic ischemic stroke. A graded increase in the risk of symptomatic ischemic stroke with decreasing levels of plasma 25(OH)D has been found in most of the studies. Vitamin D also has a role in the poststroke period where its deficiency may hinder the rehabilitation process.

Conclusions

After reviewing current literature on the subject, we conclude that there are some data to suggest the role of vitamin D in patients with stroke but it cannot be concluded as a risk factor for stroke. Larger population-based studies are needed to confirm the causative role of vitamin D in stroke.

Vitamin D Status and Related Factors among Korean Stroke Survivors: A Nationwide Population-Based Study

The aim of this study was to investigate the vitamin D status and related factors in community-dwelling Korean stroke survivors. Data of 23,872 individuals ≥20 y who participated in the Korea National Health and Nutrition Examination Surveys (KNHANES) were analyzed. Participants who had ever been diagnosed with stroke by a doctor were defined as stroke survivors (n=431). The serum 25-hydroxyvitamin D (25(OH)D) level was measured by radioimmunoassay, and vitamin D deficiency was defined as 25(OH)D<20 ng/mL. The association between vitamin D and stroke status was analyzed using multivariable general linear models and logistic regression models adjusted for sociodemographic and clinical covariates. The adjusted mean 25(OH)D level of stroke survivors was significantly lower than that of nonstroke controls; however, after adjustment for systolic blood pressure level and use of antihypertensive medication, the difference was no longer statistically significant. The burden of 25(OH)D deficiency was not higher in stroke survivors than in nonstroke controls (adjusted OR=1.14; 95% CI, 0.81-1.62). Current smoking was independently associated with 25(OH)D deficiency among stroke survivors (adjusted OR=3.17; 95% CI, 1.33-7.55). These findings indicated that treatment of high blood pressure and smoking cessation may be important measures to control vitamin D levels in stroke survivors.

Prognostic utility of serum 25-hydroxyvitamin D in patients with stroke: a meta-analysis

BACKGROUND

Conflicting findings have been reported on the prognostic significance of serum 25-hydroxyvitamin D level in patients with stroke. The objective of this meta-analysis was to evaluate the prognostic utility of serum 25-hydroxyvitamin D in stroke patients.

METHODS

PubMed and Embase databases were systematically searched for potentially eligible studies until October 16, 2019. Observational studies investigating the association between serum 25-hydroxyvitamin D level and prognosis of patients with stroke were eligible. Multivariable adjusted risk ratios (RR) with 95% confidence intervals (CI) of poor functional outcome, all-cause mortality, and recurrence of stroke were pooled with the lowest versus the highest category of 25-hydroxyvitamin D level.

RESULTS

Eleven articles (ten studies) involving 6845 stroke patients satisfied our predefined inclusion criteria. Lower serum 25-hydroxyvitamin D level was associated with an increased risk of poor functional outcome (RR 1.86; 95% CI 1.16-2.98), all-cause mortality (RR 3.56; 95% CI 1.54-8.25), and recurrence of stroke (RR 5.49; 95% CI 2.69-11.23). Sensitivity analysis further confirmed the above findings.

CONCLUSIONS

Lower serum 25-hydroxyvitamin D level is significantly associated with poorer prognosis in stroke patients. Future prospective studies are warranted to verify the prognostic role and to examine the association in different subtypes of stroke.

Vitamin D Supplementation and Post-Stroke Rehabilitation: A Randomized, Double-Blind, Placebo-Controlled Trial

Low vitamin D levels are associated with poorer outcomes after stroke. However, it is not clear whether post-stroke vitamin D supplementation can improve these outcomes. In this study, we investigated the effects of vitamin D supplementation on outcomes in hospitalized patients undergoing rehabilitation after acute stroke. A multicenter, randomized, controlled, double-blind, parallel-group trial was conducted from January 2012 through July 2017. One hundred patients admitted to a convalescent rehabilitation ward after having an acute stroke were randomized, and each one received either vitamin D3 (2000 IU/day) or a placebo. The primary outcome was a gain in the Barthel Index scores at week 8. Secondary outcomes were seen in Barthel Index efficiency, hand grip strength, and calf circumference at week 8. Ninety-seven patients completed the study. There were no significant differences in the demographic characteristics between the groups. The mean (±standard deviation) gain in the Barthel Index score was 19.0 ± 14.8 in the supplementation group and 19.5 ± 13.1 in the placebo group (p = 0.88). The Barthel Index efficiency was 0.32 ± 0.31 in the supplementation group and 0.28 ± 0.21 in the placebo group (p = 0.38). There were no between-group differences in the other secondary outcomes. Our findings suggest that oral vitamin D3 supplementation does not improve rehabilitation outcomes after acute stroke.

Association of Serum 25(OH) D Levels with Infarct Volumes and Stroke Severity in Acute Ischemic Stroke

BACKGROUND

The aim of this study is to investigate whether 25-hydroxyvitamin D [25(OH) D] is associated with initial stroke severity and infarct volume, using diffusion-weighted imaging (DWI) in patients with acute ischemic stroke.

METHODS

We studied a total of 235 patients who were admitted within 24 hours of acute ischemic stroke onset. Initial stroke severity was assessed using the NIH Stroke Scale (NIHSS) score. Infarct volume was measured using DWI. Multivariable linear and logistic regression analyses were used to test whether 25(OH) D represents an independent predictor of infarct volume and stroke severity (NIHSS score of ≥6).

RESULTS

Among 235 study patients, the median age was 64 years (IQR 56-75 years), and 125 (53.2%) were women. In multivariable models adjusted for other significant risk factors, 25(OH) D levels in the lowest and second interquartiles were associated with an increased risk of a NIHSS≥6 (with highest 25 (OH) D quartile as reference) with odd ratios (OR) 3.02(95% confidence interval [CI]:1.59-6.34) and 5.85(2.90-11.54). The median DWI infarct volumes for the serum 25(OH) D level quartiles (lowest to highest) were 12.35, 6.55, 2.44, and 1.59 ml. The median DWI infarct volume in the lowest serum 25(OH) D level quartile was larger than that in the other 3 quartiles (P<0.001). The median adjusted DWI infarct volume in the lowest serum 25(OH) D level quartile was statistically significantly larger than that in the other 3 quartiles (P<0.01).

CONCLUSION

In conclusion, reduced serum 25(OH) D levels in acute ischemic stroke are an early predictor of larger volumes of ischemic tissue and worse neurological deficit (assessed by the NIHSS).