New Review Explores the Relationship Between Vitamin D and Interferon β-1b in the Treatment of Multiple Sclerosis

European Neurological Review, the peer-reviewed journal, has published a review highlighting the problem of Vitamin D Deficiency and the Role it plays in Multiple Sclerosis

Vitamin D is not only an essential nutrient for bone homeostasis but has also been implicated in many other disorders including cardiovascular disease (CVD) and autoimmune diseases.

Here we review the problem of vitamin D deficiency and guidelines to help achieve adequate levels in both the general population and in multiple sclerosis (MS) patients and its role in MS and impact on treatment.

Although there is a lack of consensus on vitamin D deficiency and insufficiency, they have been defined as a serum level of 25(OH)D <50 nmol/L or 52.5-72.5 nmol/L, respectively.

Deficiency is common in all age groups. Vitamin D is probably involved in the prevention of a number of disease states and 25(OH)D is thought to regulate at least 2,000 genes. Vitamin D toxicity is very rare, with none seen at doses up to 20,000 IU/day.

However, the majority of primary care clinicians are not aware of the recommended dose for vitamin D supplementation and optimum serum level in terms of patients with MS. Several organisations have concluded that vitamin D screening cannot be recommended in the general population.

Guidelines have been published on treatment and prevention of vitamin D deficiency, particularly for at-risk groups and during pregnancy.

There is much evidence for the protective effects of vitamin D in MS. A higher level of sun exposure and intake of vitamin D as well as of serum 25 (OH)D, are associated with a lower risk of MS.

It also has a beneficial effect on the clinical course of MS, such as lowering the risk of relapses. Growing evidence indicates that the effects of interferon-beta are additively enhanced by 25(OH)D in MS and this may be due to its modulating vitamin D metabolism.

There are many reports suggesting an association between vitamin D status and both the development of multiple sclerosis (MS) and its course.

This relationship and the effects of vitamin D and interferon β-1b (IFNβ-1b) in the treatment of patients are reviewed in the BEtaferon/ Betaseron in Newly Emerging multiple sclerosis For Initial Treatment (BENEFIT) and the Betaferon/Betaseron Efficacy Yielding Outcomes of a New Dose in multiple sclerosis (BEYOND) studies.

In the BENEFIT study the average serum 25-hydroxyvitamin D (25[OH]D) levels strongly predicted MS disease activity and progression. The probability of clinically definite MS (CDMS) and magnetic resonance imaging (MRI) activity was lower in these clinically isolated syndrome (CIS) patients with 25(OH)D levels ≥50 nmol/L and in those starting with IFNβ -1b.

Furthermore, there was a beneficial effect on relapse rate, occurrence of new active MRI lesions and disease progression for a 50 nmol/L increase in 25(OH)D levels. Similarly, in relapsing-remitting (RR) MS patients from the BEYOND study serum 25(OH)D levels were inversely associated with MRI markers of MS activity.

Genetic analysis of patients from these studies indicated that there may be a benefit in monitoring and managing vitamin D levels in early MS patients treated with IFNβ-1b and a cumulative number of risk alleles predict lower 25(OH)D levels in CIS and RRMS patients.

Further studies have suggested that some of the IFNβ-1b therapeutic effects on relapse could be mediated through modulation of vitamin D metabolism. Thus, there seems to be a benefit on clinical and MRI measures if patients are treated with both vitamin D and IFNβ-1b. There is a need to further evaluate this effect in clinical trials. The relationship between vitamin D and MS disease activity along with the effects of vitamin D and IFNβ-1b in the treatment of MS patients is reviewed.