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MONDAY, May 6 (HealthDay News) -- Black Americans may be at higher risk for multiple sclerosis than whites, according to study findings that contradict a widely held belief that blacks are less likely to develop the neurological disease.
The theory that blacks are less likely to develop multiple sclerosis (MS) than whites was based on faulty evidence, the study authors said.
For the new study, the researchers examined three years of data from more than 3.5 million members of the Kaiser Permanente Southern California health plan and identified 496 people who were diagnosed with MS during that time.
The investigators found that blacks had a 47 percent increased risk of MS compared with whites, while Hispanics and Asians had a 58 percent and 80 percent lower risk than whites. The higher risk in blacks was seen only in women, while the lower risk for Hispanics and Asians was seen in both sexes. Black women had triple the risk of MS that black men did, the findings showed.
Blacks accounted for 21 percent of the patients diagnosed with MS, but made up only 10 percent of the total number of patients in the study. Among the other groups: whites made up 52 percent of those with MS and 38 percent of the study population; Hispanics made up 23 percent of those with MS, and 40 percent of the study population; Asians accounted for 3 percent of those with MS, and 9 percent of the study population, according to the study in the May 7 issue of the journal Neurology.
"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 [whites]," study author Dr. Annette Langer-Gould, of the Kaiser Permanente Southern California department of research & evaluation, said in a journal news release.
"About 19,000 people per year, or 250 people per week, will be diagnosed with MS in the U.S. alone. 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," she added.
The U.S. National Institute of Neurological Disorders and Stroke has more about multiple sclerosis.