Multiple sclerosis in gulf war era veterans. 2. Military deployment and risk of multiple sclerosis in the first gulf war.

BACKGROUND: Concern has been raised that US veterans of the 1990-1991 Gulf War (GW1) may be at increased risk to develop neurologic disease. METHODS: An incident cohort of multiple sclerosis (MS) and other demyelinating disease (ODD) was assembled from the US military comprising the Gulf War era (1990-2007). Cases of MS and ODD meeting standard diagnostic criteria were matched to a database of all active duty personnel from the Department of Defense. Relative risk (RR) estimates for MS and all demyelinating disease based on onset, deployment status, and exposures were calculated. RESULTS: For GW1, a total of 1,841 incident cases of definite MS and ODD were identified, with 387 among 696,118 deployed and 1,454 among 1,786,215 nondeployed personnel. The RR for MS alone among those deployed compared to those nondeployed was 0.69 (confidence interval, CI: 0.61-0.78), with 0.72 (CI: 0.62-0.83) in men and 0.96 (CI: 0.75-1.22) in women. Deployment was also nonsignificant or protective as an MS risk factor across racial groups, all age groups, and each military service. RRs for MS by service were: Air Force 0.71 (CI: 0.53-0.96), Army 0.80 (CI: 0.67-0.96), Marines 0.96 (CI: 0.63-1.47), and Navy 0.56 (CI: 0.43-0.74). CONCLUSION: Military deployment to GW1 was not a risk factor for developing MS.

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

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.