Vitamin D treatment in multiple sclerosis

Vitamin D in Multiple Sclerosis: A Comprehensive Umbrella Review

BACKGROUND

Multiple sclerosis (MS) is an inflammatory neuroimmune disease with a multifaceted etiology and long-lasting adverse effects. Several studies have explored the role of 25-hydroxyvitamin D (25(OH)D) serum levels, vitamin D receptor (VDR) gene polymorphisms, and vitamin D supplementation (VDS) in individuals with MS.

OBJECTIVES

The aim of this study was to evaluate the relationship of MS with 25(OH)D serum levels, VDR gene polymorphisms, and VDS.

METHODS

We assessed relevant articles published in PubMed, Scopus, and Web of Science from the inception up to 24 February, 2024. Meta-analyses that investigated the link of 25(OH)D serum levels, VDR gene polymorphisms including Apal (rs7975232), BsmI (rs1544410), Taql (rs731236), and Fokl (rs10735810), and VDS with the risk and clinical manifestations of MS were included. The methodological quality of selected articles was assessed by the Assessment of Multiple Systematic Reviews version 2. The statistical analysis of this umbrella review was carried out using RStudio version 2023.03.1 and R version 4.3.2, simultaneously.

RESULTS

A total of 23 of 304 records were entered into this umbrella review with a pooled sample size of 37,567 participants. Eleven articles were rated as high quality, 1 was moderate quality, 1 was low quality, and 10 were critically low quality. The homozygote model of FokI (FF+ff compared with Ff) was significantly associated with an 8% reduction of MS risk (odds ratio: 0.92, 95% confidence interval: 0.86, 0.98; I2 = 0%, P > 0.99).

CONCLUSION

According to existing clinical evidence, the risk of MS may be associated with VDR gene polymorphism. Further studies are needed to explore the association of MS and vitamin D.

TRIAL REGISTRATION NUMBER

This trial was registered at International Prospective Register of Systematic Reviews (PROSPERO) as registration number CRD42024521541.

The Effectiveness of Vitamin D Intake in Improving Symptoms and Relapses of Multiple Sclerosis: A Systematic Review

There are disagreements over the effectiveness of vitamin D supplementation in treating multiple sclerosis (MS) patients' symptoms and reducing relapses. The goal of this systematic review is to assess the effect of vitamin D supplements on improving symptoms and relapses in MS patients. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic review was conducted by searching eight databases: Embase, PubMed, Cochrane Library, MEDLINE, CINAHL, Web of Science, Scopus, and Google Scholar. The RoB 2 tool was used to evaluate the quality of the studies that were included in the analysis. From the 1,345 studies identified, 16 randomized controlled trials were selected. All studies reported that vitamin D administration significantly increased the mean serum 25(OH)D compared with the placebo group. Also, most included studies revealed a significant improvement in magnetic resonance imaging (MRI) brain lesion markers. However, most studies showed that being treated with vitamin D instead of placebo showed no significant effect on relapse rates, fatigue, Expanded Disability Status Scale (EDSS), serum neurofilament light chain (NfL), calcium, and cytokine levels, except for quality-of-life transforming growth factor beta (TGF-β). This systematic review shows that the effect of vitamin D supplements on improving symptoms and relapses during treatment in MS patients remains inconclusive.

Nuclear Receptors in Asthma: Empowering Classical Molecules Against a Contemporary Ailment

The escalation in living standards and adoption of 'Western lifestyle' has an allied effect on the increased allergy and asthma burden in both developed and developing countries. Current scientific reports bespeak an association between allergic diseases and metabolic dysfunction; hinting toward the critical requirement of organized lifestyle and dietary habits. The ubiquitous nuclear receptors (NRs) translate metabolic stimuli into gene regulatory signals, integrating diet inflences to overall developmental and physiological processes. As a consequence of such promising attributes, nuclear receptors have historically been at the cutting edge of pharmacy world. This review discusses the recent findings that feature the cardinal importance of nuclear receptors and how they can be instrumental in modulating current asthma pharmacology. Further, it highlights a possible future employment of therapy involving dietary supplements and synthetic ligands that would engage NRs and aid in eliminating both asthma and linked comorbidities. Therefore, uncovering new and evolving roles through analysis of genomic changes would represent a feasible approach in both prevention and alleviation of asthma.

The Interaction between Viral and Environmental Risk Factors in the Pathogenesis of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic debilitating inflammatory disease of unknown ethology targeting the central nervous system (CNS). MS has a polysymptomatic onset and is usually first diagnosed between the ages of 20–40 years. The pathology of the disease is characterized by immune mediated demyelination in the CNS. Although there is no clinical finding unique to MS, characteristic symptoms include sensory symptoms visual and motor impairment. No definitive trigger for the development of MS has been identified but large-scale population studies have described several epidemiological risk factors for the disease. This list is a confusing one including latitude, vitamin D (vitD) levels, genetics, infection with Epstein Barr Virus (EBV) and endogenous retrovirus (ERV) reactivation. This review will look at the evidence for each of these and the potential links between these disparate risk factors and the known molecular disease pathogenesis to describe potential hypotheses for the triggering of MS pathology.

Vitamin D receptor gene polymorphisms in multiple sclerosis disease: A case-control study

Multiple sclerosis (MS) is a common neurologic disorder that is a chronic inflammatory, demyelinating, and neurodegenerative disease of the central nervous system (CNS). Its etiology remains unknown. Several recent studies have found that decreased susceptibility to vitamin D deficiency is also associated with a decreased risk of MS. The role of vitamin D receptor (VDR) gene and its polymorphisms are highlighted as susceptible components. In this study, we aimed to identify the relationship between ApaI (rs7975232), BsmI (rs 1544410), and TaqI (rs731236) gene polymorphisms with MS. ApaI, BsmI, and TaqI genotypes were determined in 70 patients with MS and in 70 control subjects. DNA was isolated from blood samples, and then ApaI, BsmI and TaqI gene polymorphisms were identified using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. The distribution of BsmI and TaqI polymorphisms did not show any significant differences in MS patients and controls; however, increased A allele of ApaI polymorphism was found in MS patients. Our findings suggest that the ApaI gene polymorphism might be associated with MS. Investigation of a larger population and functional work on these gene structures and function in MS patients are recommended.

Selected methods of unconventional medicine and the possibilities of its usage in multiple sclerosis - analysis of the issue based on the PubMed medical database

People with multiple or long-term multiple sclerosis often use complementary or alternative medicine (CAM). CAM is considered a controversial field of treatment by both neurologists and specialists in other fields of medicine. Nevertheless, there is growing interest in this type of treatment. The aim of this study is to review literature related to the most current knowledge regarding the application of alternative medicine methods in patients suffering from multiple sclerosis based on experimental and medical studies. The method used in the study was to search and analyze the latest articles related to unconventional medicine and multiple sclerosis, available in the PubMed medical databas The most common methods of CAM usage in MS include: vitamin and mineral supplementation, intake of omega-3 and omega-6, a special diet, acupuncture, herbal medicine, reflexology, yoga and meditation. Attention has been paid to the problem which is due to high interest in alternatives. Patients with MS often use unconventional in combination with conventional medicine, while remaining under the care of doctors. Patients apply the presented method as complementary therapy, not an alternative. This article is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. null

Vitamin D deficiency is associated with disability and disease progression in multiple sclerosis patients independently of oxidative and nitrosative stress

The aim of this study was to assess vitamin D status in patients with multiple sclerosis (MS) and to evaluate whether it was associated with oxidative and nitrosative stress (O&NS) markers and disability. This study included 137 patients with MS and 218 healthy controls. The markers evaluated were serum levels of 25-hydroxyvitamin D, lipid hydroperoxides, advanced oxidation protein products (AOPP), nitric oxide metabolites (NOx), and total radical-trapping antioxidant parameter TRAP/UA. Patients with 25(OH)D<20ng/mL showed higher EDSS (p=0.016), MSSS (p=0.005) and lower AOPP (p=0.046) than those with 25(OH)D≥20ng/mL. After the binary logistic regression analyses, EDSS and MSSS remained significantly associated with vitamin D deficiency. We showed that lower levels of 25(OH)D were associated with higher EDSS and MSSS independently of variables such as O&NS, age, sex, body mass index, ethnicity, MS therapy, use of interferon beta, and clinical forms of MS (odds ratio: 1.380, 95% confidence interval 1.030-1.843, p=0.031). Moreover, the study showed an association between serum levels of 25(OH)D and EDSS (r²=0.115, p=0.002), demonstrating that 25(OH)D may contribute with 11.5% of increase in EDSS. Our results suggest that vitamin D deficiency may be considered one of the predictors of the disability in MS patients, independently of their redox status and influence the progression of disability in MS.

Osteoporosis and multiple sclerosis: risk factors, pathophysiology, and therapeutic interventions

Multiple sclerosis (MS) is a chronic inflammatory-demyelinating disease of the nervous system. There has been mounting evidence showing that MS is associated with increased risk of osteoporosis and fractures. The development of osteoporosis in MS patients can be related to the cumulative effects of various factors. This review summarizes the common risk factors and physiologic pathways that play a role in development of osteoporosis in MS patients. Physical inactivity and reduced mechanical load on the bones (offsetting gravity) is likely the major contributing factor for osteoporosis in MS. Additional possible factors leading to reduced bone mass are low vitamin D levels, and use of medications such as glucocorticoids and anticonvulsants. The role of the inflammatory processes related to the underlying disease is considered in the context of the complex bone metabolism. The known effect of different MS disease-modifying therapies on bone health is limited. An algorithm for diagnosis and management of osteoporosis in MS is proposed.

Vitamin D and multiple health outcomes: umbrella review of systematic reviews and meta-analyses of observational studies and randomised trials

OBJECTIVE

To evaluate the breadth, validity, and presence of biases of the associations of vitamin D with diverse outcomes.

DESIGN

Umbrella review of the evidence across systematic reviews and meta-analyses of observational studies of plasma 25-hydroxyvitamin D or 1,25-dihydroxyvitamin D concentrations and randomised controlled trials of vitamin D supplementation.

DATA SOURCES

Medline, Embase, and screening of citations and references.

ELIGIBILITY CRITERIA

Three types of studies were eligible for the umbrella review: systematic reviews and meta-analyses that examined observational associations between circulating vitamin D concentrations and any clinical outcome; and meta-analyses of randomised controlled trials assessing supplementation with vitamin D or active compounds (both established and newer compounds of vitamin D).

RESULTS

107 systematic literature reviews and 74 meta-analyses of observational studies of plasma vitamin D concentrations and 87 meta-analyses of randomised controlled trials of vitamin D supplementation were identified. The relation between vitamin D and 137 outcomes has been explored, covering a wide range of skeletal, malignant, cardiovascular, autoimmune, infectious, metabolic, and other diseases. Ten outcomes were examined by both meta-analyses of observational studies and meta-analyses of randomised controlled trials, but the direction of the effect and level of statistical significance was concordant only for birth weight (maternal vitamin D status or supplementation). On the basis of the available evidence, an association between vitamin D concentrations and birth weight, dental caries in children, maternal vitamin D concentrations at term, and parathyroid hormone concentrations in patients with chronic kidney disease requiring dialysis is probable, but further studies and better designed trials are needed to draw firmer conclusions. In contrast to previous reports, evidence does not support the argument that vitamin D only supplementation increases bone mineral density or reduces the risk of fractures or falls in older people.

CONCLUSIONS

Despite a few hundred systematic reviews and meta-analyses, highly convincing evidence of a clear role of vitamin D does not exist for any outcome, but associations with a selection of outcomes are probable.

Multiple sclerosis in the Arabian Gulf countries: a consensus statement

The epidemiology of multiple sclerosis (MS) is rapidly changing in many parts of the world. Based on the Kurtzke classification, the Arabian Gulf Region is located in a low-risk zone for MS; however, recent studies suggest a moderate-to-high prevalence nearby (31-55 MS per 10,0000 individuals), with an increase in incidence in recent years. The relapsing-remitting disease course ratio is 2.5:1 versus the primary progressive type. In a geographic area that was previously associated with low prevalence; the recent high prevalence and fast rising incidence of MS in the gulf countries, encouraged the neurologists of this region to meet in a consensus panel, in order to share our latest findings in terms of MS epidemiology and consent on MS management in the Arabian Gulf. Therefore 20 key opinion leader neurologists and MS experts representing various countries of the Arabian Gulf have met in Dubai on the 2 and 3 February 2012, they shared their latest epidemiological findings, discussed recent MS aspects in the region, and consented on MS management relevantly to this geographic area.

Contribution of vitamin D insufficiency to the pathogenesis of multiple sclerosis

The contribution of vitamin D insufficiency to the pathogenesis of multiple sclerosis (MS) is reviewed. Among the multiple recently discovered actions of vitamin D, an immunomodulatory role has been documented in experimental autoimmune encephalomyelitis and in humans. This action in the peripheral immune system is currently the main known mechanism through which vitamin D might influence MS, but other types of actions could be involved within the central nervous system. Furthermore, vitamin D insufficiency is widespread in temperate countries and in patients with MS at the earliest stages of the disease, suggesting that the deleterious effects related to vitamin D insufficiency may be exerted in these patients. In fact, many genetic and environmental risk factors appear to interact and contribute to MS. In genetics, several human leukocyte antigen (HLA) alleles (more particularly HLA-DRB1*1501) could favour the disease whereas some others could be protective. Some of the genes involved in vitamin D metabolism (e.g. CYP27B1) also play a significant role. Furthermore, three environmental risk factors have been identified: past Epstein-Barr virus infection, vitamin D insufficiency and cigarette smoking. Interactions between genetic and environmental risk or protective factors may occur during the mother's pregnancy and could continue during childhood and adolescence and until the disease is triggered in adulthood, therefore possibly modulating the MS risk throughout the first decades of life. Furthermore, some clinical findings already strongly suggest that vitamin D status influences the relapse rate and radiological lesions in patients with MS, although the results of adequately powered randomized clinical trials using vitamin D supplementation have not yet been reported. While awaiting these incontrovertible results, which might be long in coming, patients with MS who are currently in vitamin D insufficiency should be supplemented, at least for their general health status, using moderate doses of the vitamin.

Low levels of vitamin-D are associated with neuropathy and lymphoma among patients with Sjögren's syndrome

BACKGROUND/PURPOSE

Primary Sjögren's syndrome (SS) is a chronic autoimmune disease primarily involving the exocrine glands. The clinical picture of SS ranges from exocrinopathy to systemic disease affecting the lung, kidney, liver, skin, musculockeletal and nervous systems. The morbidity of SS is mainly determined by extraglandular disease and increased prevalence of lymphoma. Environmental and hormonal factors, such as vitamin-D may play a role in the pathogenic process and disease expression. Thus, we aimed to evaluate levels of vitamin-D and their association with manifestations of SS.

METHODS

Vitamin-D levels were determined in 176 primary SS patients and 163 matched healthy volunteers utilizing the LIAISON chemiluminescent immunoassays (DiaSorin-Italy). A correlation between vitamin-D levels and clinical and serological manifestations of SS was performed.

RESULTS

Mean vitamin-D levels were comparable between SS patients and control 21.2 ± 9.4 ng/ml and 22.4 ± 10 ng/ml, respectively. Peripheral neuropathy was diagnosed in 23% of SS patients and associated with lower vitamin-D levels (18.6 ± 5.5 ng/ml vs. 22.6±8 ng/ml (p = 0.04)). Lymphoma was diagnosed in 4.3% of SS patients, who had lower levels of vitamin-D (13.2 ± 6.25 ng/ml), compared to SS patients without lymphoma (22 ± 8 ng/ml), (p = 0.03). Other clinical and serological manifestations did not correlate with vitamin-D status.

CONCLUSIONS

In this study, low levels of vitamin-D correlated with the presence of peripheral neuropathy and lymphoma among SS patients. The link between vitamin-D and neuropathy or lymphoma was reported in other conditions, and may support a role for vitamin-D in the pathogenesis of these processes. Plausible beneficial effect for vitamin-D supplementation may thus be suggested.

Proteomic analysis of cerebrospinal fluid in a fulminant case of multiple sclerosis

Multiple Sclerosis (MS) is a chronic disease, but in rare fulminant cases rapid progression may lead to death shortly after diagnosis. Currently there is no diagnostic test to predict disease course. The aim of this study was to identify potential biomarkers/proteins related to rapid progression. We present the case history of a 15-year-old male MS patient. Cerebrospinal fluid (CSF) was taken at diagnosis and at the time of rapid progression leading to the patient’s death. Using isobaric tag labeling and nanoflow liquid chromatography in conjunction with matrix assisted laser desorption/ionization time of flight tandem mass spectrometry we quantitatively analyzed the protein content of two CSF samples from the patient with fulminant MS as well as one relapsing-remitting (RR) MS patient and one control headache patient, whose CSF analysis was normal. Seventy-eight proteins were identified and seven proteins were found to be more abundant in both fulminant MS samples but not in the RR MS sample compared to the control. These proteins are involved in the immune response, blood coagulation, cell proliferation and cell adhesion. In conclusion, in this pilot study we were able to show differences in the CSF proteome of a rapidly progressing MS patient compared to a more typical clinical form of MS and a control subject.

Dietary vitamin D3 supplements reduce demyelination in the cuprizone model

Vitamin D is emerging as a probably important environmental risk factor in multiple sclerosis, affecting both susceptibility and disease progression. It is not known to what extent this effect is due to a modulation of peripheral lymphocyte function, or to intrathecal effects of vitamin D. We investigated the effect of dietary vitamin D3 content on de/remyelination in the cuprizone model, which is a well established toxic model of demyelination, with no associated lymphocyte infiltration. The mice received diets either deficient of (<50 IU/kg), or supplemented with low (500 IU/kg), high (6200 IU/kg) or very high (12500 IU/kg) amounts of vit D3. Cuprizone (0.2%) was added to the diet for six weeks, starting two weeks after onset of the experimental diets. Mouse brain tissue was histopathologically evaluated for myelin and oligodendrocyte loss, microglia/macrophage activation, and lymphocyte infiltration after six weeks of cuprizone exposure, and two weeks after discontinuation of cuprizone exposure. High and very high doses of vitamin D3 significantly reduced the extent of white matter demyelination (p = 0.004) and attenuated microglia activation (p = 0.001). No differences in the density of oligodendrocytes were observed between the diet groups. Two weeks after discontinuation of cuprizone exposure, remyelination was only detectable in the white matter of mice receiving diets deficient of or with low vitamin D3 content. In conclusion, high dietary doses of vitamin D3 reduce the extent of demyelination, and attenuate microglia activation and macrophage infiltration in a toxic model of demyelination, independent of lymphocyte infiltration.

[Development of new therapies for multiple sclerosis]

BACKGROUND

Current first line treatment for multiple sclerosis is only moderately effective and is associated with frequent and disturbing side effects. We here describe opportunities and challenges related to drugs under development.

MATERIAL AND METHODS

Non-systematic search in PubMed and congress abstracts.

RESULTS AND INTERPRETATION

Monoclonal antibodies (e.g. natalizumab, alemtuzumab, rituximnab and dacklizumab) and oral agents (e.g. fingolimod and cladribine) target molecules or cells which are important in the immunopathogenesis of multiple sclerosis. These agents seem to have a considerable effect on relapsing-remitting multiple sclerosis, but may also be associated with serious side effects. Natalizumab is licensed as second line treatment for relapsing-remitting multiple sclerosis, and also as first line treatment in especially serious cases. Cladribine and fingolimod may be available in Norway in 2011.

INTERPRETATION

Treatment of exacerbations in multiple sclerosis is changing. Indication for the drugs under development is not yet clear.

Vitamin D and autoimmune thyroid diseases

The role of vitamin D as an immune modulator has been emphasized in recent years, and low levels of the hormone were observed in several autoimmune diseases including multiple sclerosis and systemic lupus erythematosus. Vitamin D mediates its effect though binding to vitamin D receptor (VDR), and activation of VDR-responsive genes. While VDR gene polymorphism was found to associate with autoimmune thyroid diseases (AITDs), few studies examined levels of vitamin D in these patients and those that did yielded conflicting results. We therefore undertook to evaluate the levels of vitamin D in patients with AITDs compared to patients with non-AITDs and healthy controls. Serum vitamin D (25-OH) levels were measured in 50 patients with AITDs, 42 patients with non-AITDs and 98 healthy subjects, utilizing the LIAISON chemiluminescence immunoassay (DiaSorin, Saluggia, Italy). Vitamin D deficiency was designated at levels lower than 10 ng/ml. Antithyroid antibodies, thyroid functions and demographic parameters were evaluated in all patients. The prevalence of vitamin D deficiency was significantly higher in patients with AITDs compared with healthy individuals (72% versus 30.6%; P<0.001), as well as in patients with Hashimoto's thyroiditis compared to patients with non-AITDs (79% versus 52%; P<0.05). Vitamin D deficiency also correlated to the presence of antithyroid antibodies (P=0.01) and abnormal thyroid function tests (P=0.059). Significantly low levels of vitamin D were documented in patients with AITDs that were related to the presence of anti thyroid antibodies and abnormal thyroid function tests, suggesting the involvement of vitamin D in the pathogenesis of AITDs and the advisability of supplementation.

Vitamin D, neurocognitive functioning and immunocompetence

PURPOSE OF REVIEW

Vitamin D deficiency is recognized as one of the most common medical conditions in children and adults. The major causes are inadequate sun exposure and inadequate intakes of dietary and supplemental vitamin D. Vitamin D deficiency and insufficiency defined as a 25-hydroxyvitamin D level less than 20 and 21-29 ng/ml, respectively, have been linked to increased risk for a variety of medical conditions including cancer, heart disease, type II diabetes, infectious diseases, autoimmune diseases, metabolic bone diseases and neurological disorders.

RECENT FINDINGS

The skeletal muscle and brain have a vitamin D receptor and the central nervous system has a capacity to activate vitamin D. Low vitamin D status has been linked to poor performance in neurocognitive testing in elderly. Vitamin D deficiency has been associated with muscle weakness, depression, schizophrenia, Alzheimer's disease, multiple sclerosis and a lower motor neuron-induced muscle atrophy.

SUMMARY

Correcting vitamin D deficiency and preventing vitamin D deficiency in children and adults should be a high priority for healthcare professionals to reduce risk for a wide variety of neurological disorders. Children and adults should take at least 400 international unit IU and 2000 IU vitamin D/day, respectively, to prevent vitamin D deficiency and insufficiency.

Vitamin D receptor and enzyme expression in dorsal root ganglia of adult female rats: modulation by ovarian hormones

Vitamin D insufficiency impacts sensory processes including pain and proprioception, but little is known regarding vitamin D signaling in adult sensory neurons. We analyzed female rat dorsal root ganglia (DRG) for vitamin receptor (VDR) and the vitamin D metabolizing enzymes CYP27B1 and CYP24. Western blots and immunofluorescence revealed the presence of these proteins in sensory neurons. Nuclear VDR immunoreactivity was present within nearly all neurons, while cytoplasmic VDR was found preferentially in unmyelinated calcitonin gene-related peptide (CGRP)-positive neurons, colocalizing with CYP27B1 and CYP24. These data suggest that 1,25(OH)(2)D3 may affect sensory neurons through nuclear or extranuclear signaling pathways. In addition, local vitamin D metabolite concentrations in unmyelinated sensory neurons may be controlled through expression of CYP27B1 and CYP24. Because vitamin D deficiency appears to exacerbate some peri-menopausal pain syndromes, we assessed the effect of ovariectomy on vitamin D-related proteins. Two weeks following ovariectomy, total VDR expression in DRG dropped significantly, owing to a slight decrease in the percentage of total neurons expressing nuclear VDR and a large drop in unmyelinated CGRP-positive neurons expressing cytoplasmic VDR. Total CYP27B1 expression dropped significantly, predominantly due to decreased expression within unmyelinated CGRP-positive neurons. CYP24 expression remained unchanged. Therefore, unmyelinated CGRP-positive neurons appear to have a distinct vitamin D phenotype with hormonally-regulated ligand and receptor levels. These findings imply that vitamin D signaling may play a specialized role in a neural cell population that is primarily nociceptive.

The effect of smoking on the symptoms and progression of multiple sclerosis: a review

Multiple sclerosis (MS) is a chronic inflammatory neurodegenerative disorder of the central nervous system with characteristic demyelinating lesions and axonal loss. MS accounts for the most common cause of neurological disability in young adults in the Western world. The clinical manifestations and the course of MS are highly variable. The early stage of the disease is usually characterized by attacks of neurological dysfunction with complete or incomplete recovery, however, with time disability accumulates in many patients. MS is believed to result from an interplay between susceptibility genes and environmental factors, one of which is smoking. Smoking, a worldwide epidemic, can be regarded as an important risk factor for MS particularly because of its modifiable nature in the quest to prevent or temper the disease course in MS as well as providing possible insights into MS pathogenesis. There are also reports that smoking may influence the symptoms and disease progression in patients with MS. The purpose of this article is to review the effects of smoking on MS symptoms and progression. We conclude that (1) although there are some early reports on worsening of MS symptoms by smoking, the existing evidence is insufficient to thoroughly assess the effects of smoking on the myriad of MS symptoms and (2) smoking seems to adversely influence disease progression in MS patients. We also discuss the potential biological mechanisms linking smoking and MS.

Is hypovitaminosis D one of the environmental risk factors for multiple sclerosis?

The role of hypovitaminosis D as a possible risk factor for multiple sclerosis is reviewed. First, it is emphasized that hypovitaminosis D could be only one of the risk factors for multiple sclerosis and that numerous other environmental and genetic risk factors appear to interact and combine to trigger the disease. Secondly, the classical physiological notions about vitamin D have recently been challenged and the main new findings are summarized. This vitamin could have an important immunological role involving a number of organs and pathologies, including autoimmune diseases and multiple sclerosis. Furthermore, human requirements for this vitamin are much higher than previously thought, and in medium- or high-latitude countries, they might not be met in the majority of the general population due to a lack of sunshine and an increasingly urbanized lifestyle. Thereafter, the different types of studies that have helped to implicate hypovitaminosis D as a risk factor for multiple sclerosis are reviewed. In experimental autoimmune encephalomyelitis, vitamin D has been shown to play a significant immunological role. Diverse epidemiological studies suggest that a direct chain of causality exists in the general population between latitude, exposure to the sun, vitamin D status and the risk of multiple sclerosis. New epidemiological analyses from France support the existence of this chain of links. Recently reported immunological findings in patients with multiple sclerosis have consistently shown that vitamin D significantly influences regulatory T lymphocyte cells, whose role is well known in the pathogenesis of the disease. Lastly, in a number of studies on serum levels of vitamin D in multiple sclerosis, an insufficiency was observed in the great majority of patients, including at the earliest stages of the disease. The questionable specificity and significance of such results is detailed here. Based on a final global analysis of the cumulative significance of these different types of findings, it would appear likely that hypovitaminosis D is one of the risk factors for multiple sclerosis.

Vitamin D and musculoskeletal health, cardiovascular disease, autoimmunity and cancer: Recommendations for clinical practice

BACKGROUND

There is increasing evidence that, in addition to the well-known effects on musculoskeletal health, vitamin D status may be related to a number of non-skeletal diseases. An international expert panel formulated recommendations on vitamin D for clinical practice, taking into consideration the best evidence available based on published literature today. In addition, where data were limited to smaller clinical trials or epidemiologic studies, the panel made expert-opinion based recommendations.

METHODS

Twenty-five experts from various disciplines (classical clinical applications, cardiology, autoimmunity, and cancer) established draft recommendations during a 2-day meeting. Thereafter, representatives of all disciplines refined the recommendations and related texts, subsequently reviewed by all panelists. For all recommendations, panelists expressed the extent of agreement using a 5-point scale.

RESULTS AND CONCLUSION

Recommendations were restricted to clinical practice and concern adult patients with or at risk for fractures, falls, cardiovascular or autoimmune diseases, and cancer. The panel reached substantial agreement about the need for vitamin D supplementation in specific groups of patients in these clinical areas and the need for assessing their 25-hydroxyvitamin D (25(OH)D) serum levels for optimal clinical care. A target range of at least 30 to 40 ng/mL was recommended. As response to treatment varies by environmental factors and starting levels of 25(OH)D, testing may be warranted after at least 3 months of supplementation. An assay measuring both 25(OH)D(2) and 25(OH)D(3) is recommended. Dark-skinned or veiled individuals not exposed much to the sun, elderly and institutionalized individuals may be supplemented (800 IU/day) without baseline testing.

Assessing vitamin D in the central nervous system

Epidemiological and experimental evidence suggest that vitamin D deficiency is a risk factor for multiple sclerosis and other autoimmune diseases. The activated form of vitamin D exerts several immunomodulating properties in vitro and in vivo, that could contribute to explain the association with multiple sclerosis. Hypovitaminosis D is also associated with several other neurological diseases that is less likely mediated by dysregulated immune responses, including Parkinson's disease and Alzheimer's disease, schizophrenia and affective disorders, suggesting a more diverse role for vitamin D in the maintenance of brain health. Accordingly, both the vitamin D receptor and the enzymes necessary to synthesize bioactive 1,25-dihydroxyvitamin D are expressed in the brain, and hypovitaminosis D is associated with abnormal development and function of the brain. We here review current knowledge on the intrathecal vitamin D homeostasis in heath and disease, highlighting the need to assess vitamin D in the intrathecal compartment.