May 7, 2013
Multiple Sclerosis Risk Higher For African Americans Than Whites
Brett Smith for redOrbit.com - Your Universe Online
According to the National Multiple Sclerosis Society´s official website, MS is “more common in Caucasians of northern European ancestry” than other ethnicities. However, a new study in the journal Neurology has found that African American women in particular are far more likely to contract the disease than white men and women. Both black and white men were found to have the same risk of an MS diagnosis.
"Our population-based study is the first of its kind to look at this question. The belief (that African- Americans have a lower risk of developing MS) was based on evidence that was problematic," said lead author Dr. Annette Langer-Gould of the Kaiser Permanente Southern California Department of Research & Evaluation.
According to the researchers, the previous theory on MS risk in African-Americans is based in part on a single study of disability payments given to Korean War veterans in the 1950s.
The latest study found that black women had three-times the risk of black men — which translates into a 47 percent higher overall risk of developing MS for African Americans compared to whites. The study also found a 50 percent lower risk for Hispanic patients and 80 percent lower risk for Asian patients compared to white patients.
"Our findings do not support the widely held belief that blacks have a lower risk of MS than whites, but that MS risk is determined by complex interactions between race, ethnicity, sex, environmental factors and genotypes," Langer-Gould said.
The researchers culled data from more than 3.5 million members of the Kaiser Permanente Southern California health plan“¯between January 2008 and December 2011. They were able to identify 496 people with newly diagnosed MS for their study. The team believes that this population-based study is more accurate than previous clinical studies.
While African Americans made up 21 percent of the patients with MS, they represented only 10 percent of the total study population, putting them at a disproportionately higher risk of developing MS. Whites comprised 52 percent of those diagnosed with MS and represented 38 percent of the study 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," Langer-Gould said.
The study estimates that 19,000 Americans are diagnosed with MS each year. The average person is diagnosed with MS at 41.6 years, but the study also found that onset can occur anywhere between 8.6 and 78.3 years of age. The study also found a roughly four-month window between symptom onset and MS diagnosis, but in some cases that window was as long as 40 years.
“Although additional research is needed, possible explanations for the higher incidence of MS in black women include a greater prevalence of hormonal, genetic, or environmental risk factors such as smoking, compared to patients from other racial or ethnic groups,” Langer-Gould concluded.
Multiple sclerosis is a chronic, often disabling disease that attacks the central nervous system. According to The National MS Society, more than 2.1 million people are afflicted by the disease worldwide.