The Effect of Different Administration Time and Dosage of Vitamin D Supplementation in Patients with Multiple Sclerosis: A Meta-Analysis of Randomized Controlled Trials

Vitamin D: immune function, inflammation, infections and auto-immunity

Vitamin D plays an active role beyond mineral metabolism and skeletal health, including regulation of the immune system. Vitamin D deficiency is widely prevalent, and observational studies link low vitamin D status to a risk of infections and auto-immune disorders. Reports indicate an inverse relationship between vitamin D status and such conditions. This review details vitamin D signalling interactions with the immune system and provides experimental and clinical evidence evaluating vitamin D status, vitamin D supplementation and host susceptibility to infections, inflammation and auto-immunity. The published literature including related reviews, systematic reviews, meta-analyses, randomised controlled trials (RCTs), observational studies and basic science reports have been synthesised. Meta-analyses of observational studies have demonstrated a link between low vitamin D status and risk of acute respiratory infections, COVID-19 disorders, multiple sclerosis, type 1 diabetes (T1DM), inflammatory bowel disease (IBD), systemic lupus erythematosus and other auto-immune disorders. Observational studies suggest that vitamin D supplementation may protect against several infectious and auto-immune conditions. Meta-analyses of RCTs had mixed results, demonstrating a small protective role for vitamin D supplementation against acute respiratory infections, especially in those with vitamin D deficiency and children, and providing modest benefits for the management of T1DM and IBD. Vitamin D status is inversely associated with the incidence of several infectious and auto-immune conditions. Supplementation is recommended for those with vitamin D deficiency or at high risk of deficiency, and it might provide additional benefit in acute respiratory infections and certain auto-immune conditions.

Effect of Vitamin D Supplementation on Fatigue in Multiple Sclerosis: A Systematic Review and Meta-Analysis

Vitamin D supplementation has been considered a possible treatment to reduce the risk of disease activity and progression in people with multiple sclerosis (MS). However, its effect on disease symptoms remains unclear. The aim of this meta-analysis was to conduct a systematic review to assess the effect of vitamin D on fatigue in this population. The systematic review was conducted using the MEDLINE, Cochrane Library, Embase and Web of Science databases from inception to May 2023. Randomized controlled trials (RCTs) reporting pre-post changes in fatigue after vitamin D supplementation were included. Pooled effect sizes and 95% confidence intervals (95% CIs) were calculated by applying a random effects model with Stata/SE (Version 16.0; StataCorp., College Station, TX, USA). The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. A total of five studies with 345 individuals (271 females; age range: 25.4-41.1 years) were included. A significant reduction in fatigue was perceived when vitamin D supplementation was compared with a control group: -0.18 (95% CI: -0.36 to -0.01; I² = 0%). Thus, our findings show that the therapeutic use of vitamin D on fatigue in people with MS could be considered. Nevertheless, due to the lack of agreement on the dose to be applied, it is recommended to use it under medical prescription.

Radiological Benefits of Vitamin D Status and Supplementation in Patients with MS—A Two-Year Prospective Observational Cohort Study

Current data emphasize the immunomodulating role of vitamin D in enhancing the anti-inflammatory response. Vitamin D deficiency is an established risk factor for developing multiple sclerosis—the autoimmune demyelinating and degenerative disease of the central nervous system. Several studies confirmed that higher vitamin D serum level is associated with better clinical and radiological outcomes in patients with multiple sclerosis, whereas vitamin D supplementation benefits in multiple sclerosis remain inconclusive. Despite that, many experts suggest regular measurements of vitamin D serum levels and supplementation in patients with multiple sclerosis. In this study, 133 patients with multiple sclerosis (relapsing–remitting subtype) were prospectively observed in a 0-, 12- and 24-month time span in a clinical setting. The study group consisted of 71.4% of patients (95 out of 133) supplementing vitamin D. The associations between vitamin D serum levels, clinical outcomes (disability status expressed by EDSS, number of relapses and time to relapse) and radiological outcomes (new T2-weighted lesions and number of gadolinium-enhanced lesions) were evaluated. There were no statistically significant correlations between clinical outcomes and vitamin D serum levels or supplementations. Fewer new T2-weighted lesions were observed in patients with vitamin D supplementations (p = 0.034) in 24 months of observation. Moreover, an optimal or higher level of vitamin D (>30 ng/mL) maintained throughout the entire observation period was associated with a lower number of new T2-weighted lesions in 24 months of observation (p = 0.045). These results support vitamin D implementation commencement and amelioration in patients with multiple sclerosis.

Vitamin D Supplementation Practices among Multiple Sclerosis Patients and Professionals

Vitamin D serum level increase is associated with a reduction in clinical relapse rate, gadolinium-enhancing lesions, new or enlarging T2 lesions and new active lesions in the MRI in MS patients. However, current RCTs assessing the vitamin D supplementation therapeutic effect in MS provide inconclusive results. Experts recommend vitamin D measurements and implementations among patients with MS. This article discusses an observational study, performed without any intervention to evaluate the vitamin D status and practices among MS patients and professionals in the clinical setting. A total of 139 patients with MS treated by disease-modifying therapy were recruited and fulfilled the standardized questionnaire assessing the vitamin D supplementation practices and vitamin D level influencing factors such as education, insolation, smoking, obesity and current treatment. The collected data were then compared to the patients' vitamin D serum levels available in medical records at the baseline and after 12 months of observation. Professionals' practices and recommendations were also assessed. A total of 74.1% patients confirmed vitamin D supplementation, and all patients were administered cholecalciferol, taken orally. However, only 43.69% of the patients achieved an optimal vitamin D concentration (30-50 ng/mL). The lack of a doctor's recommendation was the most frequent reason for the absence of vitamin D supplementation. The most often recommended vitamin D daily dose was 4000 IU. There was no adverse effect of supplementation observed. Vitamin D status in patients with MS is currently better than in the general population, but still, a significant percentage of patients do not implement vitamin D.

Vitamin D and Depressive Symptoms in Adults with Multiple Sclerosis: A Scoping Review

BACKGROUND

Vitamin D deficiency has been correlated with Multiple Sclerosis (MS) risk and disease activity. There is some controversy as to whether vitamin D could have an impact on depressive symptoms in people with MS (pwMS). The aim of this scoping review was to evaluate the association between vitamin D status and depressive symptoms in pwMS.

METHODS

We searched databases to include studies published up to March 2021 to provide an overview of the available evidence on the correlation between vitamin D status and depressive symptoms in pwMS. The eligibility criteria were as follows: studies evaluating the use of vitamin D measurement on depressive symptoms in patients suffering from MS, including randomized and non-randomized studies; studies written in English; and studies exploring an adult population over the age of 18.

RESULTS

Eleven studies met our inclusion criteria: two of them were abstracts only; the majority were cross-sectional studies; two were prospective longitudinal studies; one was a retrospective cohort study; and one was a randomized placebo-controlled trial (RCT). Of the eleven studies selected, seven showed a potential correlation between low vitamin D levels and depressive symptoms.

CONCLUSION

Future RCT studies should include patients with greater severity of depressive symptoms and should consider confounding factors such as sun exposure and seasonal variation of vitamin D.