The Gulf War era multiple sclerosis cohort: age and incidence rates by race, sex and service

Abstract

We characterize here a new nationwide incident cohort of multiple sclerosis from the US military-veteran population. This cohort provides an update to the only other US nationwide incidence study of multiple sclerosis performed during the 1970s. Medical records and data from the Department of Defense and Department of Veterans Affairs for cases of multiple sclerosis who served in the military between 1990, the start of the Gulf War era, and 2007 and who were service-connected for this disorder by the Department of Veterans Affairs from 1990 on, were reviewed. A total of 2691 patients were confirmed as having multiple sclerosis: 2288 definite, 190 possible, 207 clinically isolated syndrome and six neuromyelitis optica. Overall racial categories were White, Black and other, which included all Hispanics. There were 1278 White males and 556 females; 360 Black males and 296 females; and 200 others, 153 (77%) of whom were Hispanic. Mean age at onset of 30.7 years did not differ significantly by race or sex. Age at onset was 17-50 years in 99%, the same age range as 99% of the military. Average annual age specific (age 17-50 years) incidence rates per 100 000 for the entire series were 9.6 with 95% confidence interval of 9.3-10.0. Rates for Blacks were highest at 12.1 with confidence interval 11.2-13.1, Whites were 9.3 (interval 8.9-9.8) and others 6.9 (interval 6.0-7.9). For 83 Hispanics defined for 2000-07, the rate was 8.2 (interval 6.5-10.1). Much smaller numbers gave rates of 3.3 for Asian/Pacific Islanders and 3.1 for native Americans. Rates by sex for Whites were 7.3 and 25.8 male and female, respectively, for Blacks 8.4 and 26.3, and for Hispanics 6.6 and 17.0. Rates by service were high for Air Force (10.9) and Army (10.6), medium for Navy (9.1) and Coast Guard (7.9), and low for Marines (5.3). Relative risk of multiple sclerosis was 3.39 female:male and 1.27 Black:White. These new findings indicate that females of all races now have incidence rates for multiple sclerosis some three times those of their male counterparts and that among these groups, Blacks have the highest and others (probably including Hispanics) the lowest incidence rates regardless of sex or service. The low rate for Marines is unexplained. This Gulf War era multiple sclerosis cohort provides a unique resource for further study.

Multiple sclerosis in US minority populations

“…7 Likewise, a contemporary study of 2,691 Gulf War-era military veterans with MS found that the incidence rate per 100,000 was higher in African Americans (12.1) than in Caucasian Americans (9.3), Hispanic Americans (8.2), Asian Americans (3.3), or Native Americans (3.1). 8 These findings and support the increasing awareness of MS among other minority populations. 7 Regarding clinical manifestations of disease, African Americans are more likely to have an older age at disease onset, whereas Hispanic Americans may have an earlier age at disease onset compared with other patient cohorts.…”

“…For example, African Americans had a mean age at symptom onset of 38.3 years in the retrospective cohort study, 7 and 30.8 and 29.9 years for African American men and women, respectively, in the study of Gulf War-era military veterans. 8 Notably, although the ages at symptom onset and MS diagnosis vary between patient populations, the length of diagnostic delay appears to be consistent between groups in the various studies. Mean time from symptom onset to diagnosis was 2.0 years in the retrospective cohort study 7 and 2.6 years in the military veterans study.…”

“…Although variations in the definitions for many of the ethnic minorities were presented in the literature, they have been standardized for the purpose of this review. Only 2 articles describe the incidence of adult-onset MS across several racial and ethnic groups within the United States, 7,8 while others have evaluated specific comparisons between 2 ethnic patient groups. 4,9,10 Among the studies reviewed, ethnic differences were noted in overall incidence of disease, characteristics at onset of MS including age at onset, length of diagnostic delays, and disability at diagnosis, as well as characteristics over the course of the disease.…”

“…Mean time from symptom onset to diagnosis was 2.0 years in the retrospective cohort study 7 and 2.6 years in the military veterans study. 8 While the earlier onset of disease adds to the concern that Hispanic Americans may also develop increased disability at an earlier age than other populations, the more aggressive disease course experienced by many African American patients also places them at an increased risk for disability. In support of this, African Americans were found to have a higher average Multiple Sclerosis Severity Score (MSSS) compared with Caucasian Americans (5.6 vs 4.5; p , 0.001) at diagnosis.…”

Adjustment modes in the trajectory of progressive multiple sclerosis: a qualitative study and conceptual model

“…13 reflect the prevalence ratio of women to men in MS (2.3-3.5:1) (Ahlgren, Oden, & Lycke, 2011;Wallin et al, 2012). Half of the sample was unemployed or retired due to MS (n=19, 56%).…”