Low vitamin D levels are known to be associated with an increased risk of multiple sclerosis (MS), but how that association affects disease course is unknown. Now, research indicates that higher levels of vitamin D may not only play a role in MS disease activity, but help improve symptoms associated with disease progression.
In order to assess the association between 25(OH)D serum levels and MS, Alberto Ascherio, MD, DrPH, of the Harvard T.H. Chan School of Public Health, and colleagues studied the effects of vitamin D levels in patients with relapsing-remitting MS (RRMS) treated with interferon beta-1b.
The study, published in JAMA Neurology, included 1,482 participants from the Betaferon Efficacy Yielding Outcomes of a New Dose (BEYOND) study who were randomized to receive 250 μg or 500 μg of interferon-1b with at least two measurements of 25(OH)D at six months apart. MRI was performed at baseline and annually thereafter, with patients monitored for at least two years.
The researchers found that average vitamin D levels were significantly inversely correlated with the cumulative number of new active lesions between baseline and last MRI, with a 50.0-nmol/L increase in serum 25(OH)D levels associated with a 31% lower rate of new lesions (relative rate [RR], 0.69; 95% CI, 0.55-0.86; P = .001). Participants with vitamin D levels greater than 100.0 nmol/L (RR, 0.53; 95% CI, 0.37-0.78; P = .002) had the lowest rate of new lesions. Results remained consistent after adjusting for HLA-DRB1*15 or vitamin D–binding protein status. Notably, no significant associations were found between vitamin D levels and changes in brain volume, MS relapse rates, or EDSS scores.