Vitamin D levels predict multiple sclerosis progression

Among people with early-stage multiple sclerosis (MS), those with higher blood levels of vitamin D had better outcomes during 5 years of follow-up. Identifying and correcting vitamin D insufficiency could aid in the early treatment of MS.

MS is an unpredictable disease of the central nervous system that disrupts communication between the brain and other parts of the body. It's believed to be an autoimmune disease, in which the immune system mistakenly attacks the myelin sheaths that insulate nerves. The disease can range from relatively mild to devastating.

People who have low levels of vitamin D intake or low blood levels of vitamin D have a higher risk for MS. This suggests that vitamin D is related to the disease, but it's unclear whether low vitamin D levels are a cause or a consequence of MS.

An international team of researchers, led by Dr. Alberto Ascherio of Harvard School of Public Health, set out to assess whether vitamin D status early in the disease process influences the long-term course of the disease. The study was funded in part by NIH's National Institute of Neurological Disorders and Stroke (NINDS). It appeared online on January 20, 2013, in JAMA Neurology.

The team examined data from 465 people with early-stage MS who were enrolled in a large clinical trial originally designed to evaluate an MS drug called interferon beta-1b. The participants - from 18 European countries, Israel, and Canada-were mostly white individuals of European ancestry.

A common marker of vitamin D status-serum concentrations of 25-hydroxyvitamin D (25[OH]D) - was measured at baseline (the onset of symptoms) and 6, 12, and 24 months later. Participants were followed for 5 years with clinical assessments and MRI scans to monitor brain lesions and brain volume. Data were adjusted for age, sex, body mass index, and seasonal variation in vitamin D levels.

The researchers found that higher serum 25(OH)D levels in the first 12 months predicted reduced MS activity and a slower rate of MS progression. By the end of the follow-up at 5 years, participants with serum 25(OH)D concentrations of at least 50 nmol/L (20-ng/mL, a moderate level) had significantly fewer new active lesions, a slower increase in brain lesion volume, lower loss of brain volume, and lower disability than those with serum 25(OH)D concentrations below 50 nmol/L. These results suggest that vitamin D has a protective effect on the disease process underlying MS.

''The benefits of vitamin D appeared to be additive to those of interferon beta-1b, a drug that is very effective in reducing MS activity,'' Ascherio says. ''The findings of our study indicate that identifying and correcting vitamin D insufficiency should become part of the standard of care for newly diagnosed MS patients.''