Contrary to a widely accepted belief, African American women may have a higher rather than lower risk of developing multiple sclerosis compared with Caucasians, according to a new study.
Annette Langer-Gould, MD, with the Kaiser Permanente Southern California Department of Research & Evaluation in Pasadena, Calif., said the belief that African Americans have a lower risk of developing MS “was based on evidence that was problematic.”
For the study, which appeared in the journal Neurology, researchers examined the entire database of more than 3.5 million members of the Kaiser Permanente Southern California health plan over a three-year period and identified 496 people with newly diagnosed MS. Such a population-based study is considered a more accurate way to determine disease risk than to examine only those people who attend a specific clinic or hospital, the researchers noted.
The study found that African Americans had a 47% increased risk of MS compared with Caucasians, while Hispanics and Asians had a 58% and 80% lower risk than Caucasians.
Sex differences in MS risk also were highlighted in the study. The higher risk in African Americans was found in women only, whereas the lower risk for Hispanics and Asians was found in both sexes. African-American women had triple the risk of MS compared with African-American men.
African-Americans made up 21% of those with MS despite comprising only 10% of the total study population. Caucasians made up 52% of those with MS, compared with 38% of the study population. A total of 23% of those with MS were Hispanic, compared with 40% of the total population. Asians made up 3% of those with MS, compared with 9% of the population.
“One explanation for our findings is that people with darker skin tones have lower vitamin D levels and, ultimately, an increased risk, but this would not explain why Hispanics and Asians have a lower risk than Caucasians,” said Langer-Gould, a Fellow of the American Academy of Neurology, noting that about 19,000 people per year and 250 people per week will be diagnosed with MS in the United States.
“These numbers highlight the need for more minorities to be included in MS studies, so that we can fully understand how race may play a role in developing the disease.”
Read the study abstract: www.neurology.org/content/80/19/1734.abstract.