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

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.

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.

Compositional and functional alterations of gut microbiota in patients with stroke

BACKGROUND AND AIMS

There is accumulating evidence that gut microbiota plays a key role in cardiovascular diseases. Gut bacteria can transform dietary choline, l-carnitine, and trimethylamine N-oxide (TMAO) into trimethylamine, which can be oxidized into TMAO again in the liver. However, the alterations of the gut microbiota in large artery atherosclerotic (LAA) stroke and cardioembolic (CE) stroke have been less studied.

METHODS AND RESULTS

We performed a case-control study in patients with LAA and CE types of strokes. We profiled the gut microbiome using Illumina sequencing of the 16S ribosomal RNA gene (V4-V5 regions), and TMAO was determined via liquid chromatography-tandem mass spectrometry. Our results showed that the TMAO levels in the plasma of patients with LAA and CE strokes were significantly higher than those in controls (LAA stroke, 2931 ± 456.4 ng/mL; CE stroke, 4220 ± 577.6 ng/mL; healthy control, 1663 ± 117.8 ng/mL; adjusted p < 0.05). The TMAO level in the plasma of patients with LAA stroke was positively correlated with the carotid plaque area (rho = 0.333, 95% CI = 0.08-0.55, p = 0.0093). Notably, the composition and the function of gut microbiota in the LAA stroke group were significantly different from those in the control group (FDR-adjusted p-value < 0.05). There was no significant association between gut microbiota and CE stroke in our study.

CONCLUSION

This study provides evidence for significant compositional and functional alterations of the gut microbiome in patients with LAA stroke. Gut microbiota might serve as a potential biomarker for patients with LAA stroke.

Risk Factors of Vitamin D Deficiency in Chinese Ischemic Stroke Patients: A Cross-Sectional Study

Purpose

Lower serum vitamin D has been reported to be associated with stroke. This study aimed to analyze the risk factors of vitamin deficiency in Chinese stroke patients, and further analyze its impact in different gender and their clinical variables.

Methods

982 stroke patients were enrolled. Laboratory parameters such as serum vitamin D, apolipoprotein A-I (ApoA-I), apolipoprotein B (ApoB), ApoA-I/ApoB, cholesterol (CH), fibrinogen (FIB), blood glucose (Glu), high-density lipoprotein (HDL), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) were collected and recorded. The severity of stroke was assessed by National Institute of Health Stroke Scale (NIHSS) score. Based on their serum vitamin D level, patients were divided into three groups: Vitamin D deficiency (<50 nmol/L), vitamin D insufficiency (≥50–75 nmol/L) and vitamin D sufficiency (≥75 nmol/L) and differences were compared among the three groups. Statistical analyses were done to assess the risk factors for serum vitamin D deficiency in our ischemic stroke patients.

Results

Gender, NIHSS, and FIB showed significant differences among the vitamin D groups (P < 0.001 ∼ P = 0.002). The female gender (OR = 2.422, P < 0.001), severity of stroke using NIHSS (OR = 1.055, P = 0.008) and FIB (OR = 1.256, P = 0.005) were risk factors of vitamin D deficiency in ischemic stroke patients. In subgroup analysis, NIHSS was significantly associated with vitamin D deficiency in the male group (OR = 1.087, P = 0.002) and higher FIB group (OR = 1.078, P = 0.001).

Conclusions

The female gender, severity of stroke using NIHSS and FIB were risk factors for vitamin D deficiency in our incident stroke patients. NIHSS was more sensitive to vitamin D deficiency in male ischemic stroke patients. Besides, under higher FIB circumstance, the increasing NIHSS score was more related to the vitamin D deficiency. Levels of vitamin D in patients with ischemic stroke should be well monitored during the disease cascade.

Effect of vitamin D and/or omega-3 fatty acid supplementation on stroke outcomes: A randomized trial

BACKGROUND AND PURPOSE

Among stroke patients, low serum 25-hydroxyvitamin D predicts poor outcomes. In mice, higher omega-3 (n-3) fatty acid intake diminishes brain damage after stroke. In this study, we tested whether vitamin D or n-3 fatty acids supplementation prior to stroke reduces the risk of functional limitations and physical disability after stroke.

METHODS

We used data from VITAL (the VITamin D and OmegA-3 TriaL) which randomized middle-aged and older men and women without cardiovascular disease to vitamin D₃ (2000 IU/day) and/or marine n-3 fatty acids (1 g/day) and followed them for incident stroke events. Individuals experiencing a non-fatal stroke were mailed questionnaires assessing functional limitations (the physical performance scale adapted from Nagi) and physical disability (the modified Katz Activities of Daily Living and Rosow-Breslau Functional Health scales). We used logistic regression to analyze associations between randomized treatment and limitations on each scale.

RESULTS

A total of 290 individuals experienced their first stroke during the trial, of whom 197 stroke survivors completed the stroke outcomes questionnaire a median of 1.4 years after diagnosis. We observed no associations between randomized treatment to vitamin D and functional limitations (odds ratio [OR] 1.01, 95% confidence interval [CI] 0.52, 1.97) or physical disability (Rosow-Breslau scale: OR 0.92, 95% CI 0.50, 1.67; Katz scale: OR 1.03, 95% CI 0.31, 3.42). Those randomized to n-3 fatty acids had a non-significantly lower risk of functional limitations (OR 0.55, 95% CI 0.28, 1.09) and physical disability (Rosow-Breslau scale: OR 0.56, 95% CI 0.31, 1.02; Katz sclae: OR 0.32, 95% CI 0.50, 1.67).

CONCLUSION

Vitamin D or omega-3 fatty acid supplementation prior to stroke did not result in significantly improved post-stroke outcomes.