By Sandra Basu
BALTIMORE — Why are incident rates for multiple sclerosis (MS) increasing in African-Americans compared with other racial backgrounds, and why is the disease, on average, more severe in that population?
Those are among the questions plaguing VA and military researchers as they try to respond to the trends and provide appropriate care to patients.
Christopher Bever, MD, who serves as director of VA’s MS Center of Excellence (MSCoE) East, told U.S. Medicine that MS in African-Americans has been “shifting” and it is an area of “active study” both by VA and by others.
“African-American patients oftentimes have more impairment and more disability, and so we are working in our programs to make sure we can deal with the more severe consequences of MS,” Bever noted. “Many of those problems turn out to be like the problems seen in the spinal injury population because MS does affect the spinal cord.”
MS and Race
Two recently published studies on MS demographics in certain segments of the military population raise issues about race and disease incidence.
One of the studies, published in 2012 by VA researchers, examined Gulf War medical records and data from the DoD and VA for cases of MS in servicemembers who served in the Gulf War era between 1990 and 2007 and who were service-connected for the disorder by VA from 1990 on.
For the study, active duty population data were obtained for each year 1990-2000 and 2001-10 from the Defense Medical Epidemiological Database. In the study, a total of 2,691 patients were confirmed as having MS.
What the researchers called “novel,” was their findings that the black veterans had a higher incidence rate of MS (12.1 per 100,000 persons) than white veterans (9.3 per 100,000 persons).
“Potential explanations for the high multiple sclerosis incidence rates for blacks are important to explore,” the researchers wrote, noting that, historically, MS rates have been higher in whites. Based on their prior work with military cohorts, the researchers wrote that “these changes have manifested themselves fairly recently, over the past two to three generations.”
Environmental risk factors as well as genetic susceptibility were among the factors that the authors said should be explored to better understand their observations.
Another 2012 study, published in Military Medicine, examined estimated incidence of MS among military personnel from 2000 to 2009, also finding that black non-Hispanics had a higher incidence rate than white non-Hispanics, at 18.3 per 100,000 person-years vs. 12.5 per 100,000 person-years, respectively. That study also indicated that black females had higher rates than their white counterparts.
“[Incidence rates] of MS diagnoses among blacks, and specifically black females, were higher than their white counterparts. This relationship in an adult population has not been previously seen in literature and has only recently been described in children. The novelty of this finding is perplexing,” the study stated. “Do these results represent an unidentified risk factor in our population among black females, or are these results representative of actual risk not previously appreciated in the general U.S. population?”