Multiple Sclerosis May Be Influenced by Race and Vitamin D Levels

Race and vitamin D levels may play a crucial role in the risk of multiple sclerosis (MS), according to Annette M. Langer-Gould, MD, PhD, of Kaiser Permanente in Pasadena, California. The findings are set to be presented in a poster session at the 31^st Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS 2015) in Barcelona, Spain.

Previous research has linked lower vitamin D levels with an increased risk of MS — but only in Caucasians. Langer-Gould and her team set out to see if the true could be said about African Americans and Hispanics. They looked at patients with newly diagnosed MS or clinically isolated syndrome (CIS), the precursor, between 2011 and 2014.

The researchers gathered data from 929 individuals (457 with MS/CIS and 472 healthy controls) through interviews, blood tests, and complete electronic health records. Patients and controls were matched for age, sex, race/ethnicity, and zip code:

• Caucasian: 203 patients, 205 controls
• African American: 108 patients, 116 controls
• Hispanic: 146 patients, 151 controls

Overall, Caucasians had the highest levels of 25-hydroxyvitamin D (average of 70nmol/L) followed by Hispanics (55nmol/L) and African Americans (47nmol/L). Higher vitamin D levels were associated with lower risk of MS/CIS in Caucasians, especially those with levels over 75nmol/L. However, the findings did not show a correlation between vitamin D levels and MS/CIS risk in African Americans or Hispanics.

“A non-causal association cannot be excluded as vitamin D is a better surrogate measure of sunlight exposure in light than dark-skinned individuals,” the authors explained. “Another possible explanation is complex interactions between vitamin D and genotype as several genes that increase vitamin D bioavailability are more common in blacks.”

Prescribing vitamin D to prevent MS is premature, the team advises. The research reaffirms the importance of considering race in vitamin D studies.