Major study exploring the connection between vitamin D and multiple sclerosis in African Americans, a team of scientists at the University of California, San Francisco has discovered that vitamin D levels in the blood are lower in African Americans who have the disease, compared to African Americans who do not.
UCSF Multiple Sclerosis Center, director of the UCSF Neurodiagnostics Center and the senior author on the study. “Low vitamin D levels are a risk factor for developing multiple sclerosis.”
Published this week in the journal Neurology, the results of the study are consistent with observations in Caucasian populations that link low vitamin D levels to having multiple sclerosis. However, the research could not explain why multiple sclerosis tends to be more severe in African Americans even though the disease is less common than in Caucasian populations.
Earlier work by the same UCSF team established that African Americans tend to become disabled faster with multiple sclerosis, more frequently having to rely on canes and wheel chairs.
“If we can understand why, we may be able to improve treatment for those patients,” said neurologist Bruce Cree, MD, PhD, another author of the paper and one of the primary investigators.
Vitamin D levels alone could not account for this apparent difference in severity, the study found.
Previous studies have shown a dramatic link between vitamin D levels and multiple sclerosis – but only in Caucasian populations. Caucasians who live in tropical or subtropical climates are less likely to be diagnosed with multiple sclerosis than those who live in temperate climates. The prevalence of the disease in North Dakota, for instance, is approximately twice that in Florida.
These same questions have been harder to assess in African American populations, however, because the prevalence of vitamin D deficiency is extremely high among all African Americans.
For the last 10 years, Cree and colleagues at UCSF have created a nationwide network of U.S. clinics that treat large numbers of African Americans with the disease. It includes roughly 6 percent of all African Americans who have multiple sclerosis and live in the United States.
This large cohort of African Americans with multiple sclerosis allowed them to compare 339 African Americans with multiple sclerosis to those of a group of 342 African Americans who did not have the disease. Though vitamin D deficiency was very high among both groups, those who had multiple sclerosis were more likely to be vitamin D deficient – 77 percent as opposed to 71 percent.
The article “Vitamin D in African Americans with multiple sclerosis” is authored by Jeffrey M. Gelfand,Bruce A. C. Cree, Joseph McElroy, Jorge Oksenberg, Ralph Green, Ellen M. Mowry, Joshua W. Miller, Stephen L. Hauser and Ari J. Green.
The study was supported by the American Academy of Neurology Foundation/National Multiple Sclerosis Society Clinician-Scientist Development Award, the National Institutes of Health, the National Multiple Sclerosis Society and a University of California-San Francisco Resident Research grant. The work was completed in collaboration with Drs. Ralph Green and Josh Miller of the University of California, Davis Department of Pathology.
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