The rate of multiple sclerosis (MS) cases varies greatly by race and ethnicity. A new study suggests that the prevalence of MS in Black and white people is similarly high, while much lower in Hispanic and Asian people. The research is published in the April 27, 2022, online issue of Neurology^®, the medical journal of the American Academy of Neurology.

“MS has long been believed to be a disease of white people, but the prevalence of MS in Black people has been understudied and therefore underrecognized,” said study author Annette Langer-Gould, MD, PhD, of Kaiser Permanente Southern California in Los Angeles and a member of the American Academy of Neurology. “The findings of our study and other recent studies indicate that MS has affected Black and white adults at similar rates for decades.”

Langer-Gould said, “The belief that MS is rare in Black people has been based on a history of problematic evidence, including a 1950s study of veterans that found white men more likely than Black men to receive services through the Veterans Administration for MS. That study did not consider the barriers and disparities Black men faced in receiving services, and that they were less likely to be measured accurately.”

Langer-Gould also notes that even current research uses the terms Hispanic, Asian, Black, and white, which are socially constructed labels that influence social standing and opportunities for advancement in the U.S., not uniform biological or even cultural differences. She said it’s crucial that new research addresses systemic bias in medical research.

This new study looked at more than 2.6 million adults residing in Southern California. Researchers analyzed Kaiser Permanente health records to determine how many people had a confirmed diagnosis of MS in 2010.

Researchers identified 3,863 people with MS. The average age was 52 and 77% were women.

Researchers found that MS prevalence per 100,000 people was similarly high for Black and white people, occurring in 226 per 100,000 Black people and in 238 per 100,000 white people. MS prevalence was lower among Hispanic and Asian people, occurring in 70 per 100,000 Hispanic people and 23 per 100,000 Asian people.

The percentage of women with MS was more pronounced among Black and Asian people. Of Black people with MS, 82% were women and of Asian people, 84% were women. Of white people with MS, 76% were women and of Hispanic people, 75% were women.

“Understanding MS prevalence in all people has important implications when it comes to making sure people are properly screened and treated for this disease,” said Langer-Gould.

“More studies are needed to determine whether MS is also an emerging disease among Hispanic people in the U.S. and whether MS susceptibility and prevalence vary among Hispanic or Asian individuals from different cultures and ancestral backgrounds,” Langer-Gould added. “Larger studies are also needed that look at bigger populations across the U.S.”