Vitamin-D Levels Inversely Correlated With Disability and Disease Progression in Multiple Sclerosis

Emma Hitt, PhD

June 02, 2009

June 2, 2009 (Atlanta, Georgia) — Vitamin-D deficiency may be associated with a higher disability score and increased rate of disease progression for patients with multiple sclerosis (MS), new research findings suggest.

Allison Drake, a researcher with the Jacobs Neurological Institute at the State University of New York (SUNY) Buffalo School of Medicine and Biomedical Sciences, presented the findings here at the Consortium of Multiple Sclerosis Centers (CMSC) 23rd Annual Meeting.

Vitamin D has been implicated as a risk factor for MS, the investigators note. In addition, preclinical in vivo studies have demonstrated that vitamin D may inhibit experimental autoimmune encephalomyelitis and prevent disease progression.

In the current analysis, the researchers collected data from 349 patients with MS included in the New York State Multiple Sclerosis Consortium (NYSMSC). Patients' mean age was 50.5 years. In addition to the Expanded Disability Status Scale (EDSS), the Multiple Sclerosis Severity Scale (MSSS) was used to measure the rate of disease progression. A patient was considered to be deficient in vitamin D if serum levels were < 20 ng/mL.

Of the patients evaluated, 21.8% of patients were deemed deficient in vitamin D. "It is important to note that the majority of patients had less than sufficient levels of serum vitamin D," said Ms. Drake. "Even during 'peak months,' few patients were able to reach sufficient levels. This observation was especially apparent in patients with severe disability," she said.

Linear regression analysis found that vitamin-D deficiency (P < 0.001) and MS disease subtype (P < 0.001) were the only factors that significantly predicted MSSS. Other factors evaluated were sex and age, and these did not show an effect.

"The results of this study are consistent with previous reports, including a population-based study, a case-control study, and longitudinal studies, demonstrating that serum vitamin-D levels are associated with MS," Ms. Drake told Medscape Neurology & Neurosurgery.

According to the researchers, vitamin-D levels may have a protective role in MS if levels are sufficient or a detrimental effect if levels are insufficient.

"This study raises the question of what's the chicken and what's the egg," said Stuart D. Cook, MD, a professor in the departmentofneurology and neuroscience at the University of Medicine and Dentistry, in Newark, New Jersey, who attended the presentation. "People with MS have heat sensitivity, or they may be disabled and less inclined to go outside, so they may have a decreased exposure to the sun and lower vitamin-D levels as a consequence of their disability."

Still, he pointed out, "This is not to invalidate the vitamin-D hypothesis — there is a lot of evidence saying that vitamin D is an important factor in MS susceptibility in general," he told Medscape Neurology & Neurosurgery.

According to Dr. Cook, there is a good rationale for activity of vitamin D in MS. "Vitamin D has multiple effects, including the fact that it can downregulate the immune response, which we think is important in MS; it can interact with the genes that predispose to MS, potentially upregulating or downregulating those genes," he said. "So there are a lot of potential mechanisms that could explain how vitamin D might work."

The study was supported by the 2008 Foundation of the Consortium of Multiple Sclerosis Centers Summer Research Scholar Program and EMD/Serono. Ms. Drake and Dr. Cook report no relevant funding disclosures.

The Consortium of Multiple Sclerosis Centers (CMSC) 23rd Annual Meeting and 2nd joint meeting of the American Committee for Treatment and Research in MS (ACTRIMS): Abstract P07. Presented May 29, 2009.


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