STANFORD, CA — Multiple sclerosis affects diverse racial and ethnic groups in the United States, according to a recent study, which suggested that “racial, ethnic, and geographic differences in multiple sclerosis (MS) are important factors to assess when determining the disease burden and allocating health care resources.”
The report in JAMA Neurology also reported that, in line with past studies, “Prevalence of MS increases significantly and nonuniformly with latitude in the United States, even when adjusted for race, ethnicity, age, and sex.”1
The Stanford University School of Medicine-led study involved researchers from the VA’s Multiple Sclerosis Center of Excellence in Baltimore. It sought to calculate the U.S. prevalence of MS in Hispanic, non-Hispanic Black and non-Hispanic white individuals stratified by age, sex, and region.
To do that, the study team applied a validated algorithm to private, military and public (Medicaid and Medicare) administrative health claims data sets to identify adult cases of MS between 2008 and 2010. Data analysis occurred between 2019 and 2022.
The researchers noted that the 3-year cumulative prevalence overall was determined in each data set and stratified by age, sex, race, ethnicity and geography. The insurance pools included 96 million persons from 2008 to 2010, with insurance and stratum-specific estimates applied to the 2010 US Census data and the findings combined to calculate the 2010 prevalence of MS cumulated over 10 years.
The study identified 744,781 adult patients as having MS—564,426 cases (76%) in females and 180 355 (24%) in males. The median age group was 45 to 54 years, which included 229, 216 patients (31%), with 101,271 aged 18 to 24 years (14%), 158,997 aged 35 to 44 years (21%), 186,758 aged 55 to 64 years (25%) and 68,539 (9%) who were 65 years or older.
The researchers reported that white patients made up the largest group, 77%, followed by 10% Black patients, 7% Hispanic patients and 4% in the non-Hispanic “other” category.
The study team calculated that the estimated 2010 prevalence of MS per 100,000 U.S. adults cumulated over 10 years was 161.2 (95% CI, 159.8-162.5) for Hispanic individuals (regardless of race), 298.4 (95% CI, 296.4-300.5) for Black individuals, 374.8 (95% CI, 373.8-375.8) for white individuals and 197.7 (95% CI, 195.6-199.9) for individuals from non-Hispanic other racial and ethnic groups.
“During the same time period, the female to male ratio was 2.9 overall,” the authors wrote. “Age stratification in each of the racial and ethnic groups revealed the highest prevalence of MS in the 45- to 64-year-old age group, regardless of racial and ethnic classification.”
In terms of geography, they wrote, “With each degree of latitude, MS prevalence increased by 16.3 cases per 100,000 (95% CI, 12.7-19.8; P < 0.001) in the unadjusted prevalence estimates, and 11.7 cases per 100,000 (95% CI, 7.4-16.1; P < 0.001) in the direct adjusted estimates. The association of latitude with prevalence was strongest in women, Black individuals, and older individuals.”
- Hittle M, Culpepper WJ, Langer-Gould A, Marrie RA, et. al. Population-Based Estimates for the Prevalence of Multiple Sclerosis in the United States by Race, Ethnicity, Age, Sex, and Geographic Region. JAMA Neurol. 2023 May 15:e231135. doi: 10.1001/jamaneurol.2023.1135. Epub ahead of print. PMID: 37184850; PMCID: PMC10186207.
