Vitamin D status associated with multiple sclerosis activity, progression

Higher vitamin D levels appear to be associated with reduced disease activity and a slower rate of disease progression in multiple sclerosis (MS) patients treated with interferon beta-1b, according to a study.

The Betaferon/Betaseron in Newly Emerging multiple sclerosis For Initial Treatment (BENEFIT) study was originally designed to evaluate the impact of early versus delayed interferon beta-1b treatment in MS. From these data, researchers examined whether blood concentration of 25-hydroxyvitamin D was associated with disease activity and progression in patients with a first episode suggestive of MS.

Patients had blood serum levels taken to measure vitamin D status and MRI scans to measure disease progression for up to 5 years. Results appeared online Jan. 20 at JAMA Neurology.

During the 5 years of follow-up, 377 patients (81.3%) converted to MS defined by clinical criteria and MRI (McDonald et al MS criteria [MDMS]) and 216 (46.6%) converted to MS defined by purely clinical criteria (modified Poser et al criteria [CDMS]). Conversion rates decreased with increasing serum levels of vitamin D, more strongly after 6 months than before. Mean serum levels at 12 months predicted subsequent conversions to MDMS (P=0.02) and CDMS (P=0.05).

Higher serum vitamin D levels predicted reduced MS activity and slowed the rate of progression. A 50-nmol/L (20-ng/mL) increase in average serum levels within the first 12 months was associated with:

• a 57% lower rate of new active MRI lesions between 12 and 60 months and a 63% lower rate between 24 and 60 months,
• a 57% lower relapse rate (P=0.03),
• a 25% lower yearly increase in T2 lesion volume (P<0.001), and
• a 0.41% lower yearly loss in brain volume (P=0.07) from months 12 to 60.

Vitamin D levels greater than or equal to 50 nmol/L (20 ng/mL) at up to 12 months predicted lower disability on the Expanded Disability Status Scale (score, −0.17; P=0.004) during the next 4 years.

While more research is needed to assess what levels of vitamin D might be most beneficial, researchers noted, “The results of our study reveal a robust prognostic value of vitamin D levels measured early in the MS course and converge with previous epidemiological and biological evidence supporting a protective effect of vitamin D on the disease process underlying MS, and thus the importance of correcting vitamin D insufficiency, which affects about 50% of patients with MS in Europe and 20% in the United States.”