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, Cl: 0.61-0.78), with 0.72 (Cl: 0.62-0.83) in men and 0.96 (Cl: 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 (Cl: 0.53-0.96), Army 0.80 (Cl: 0.67-0.96), Marines 0.96 (Cl: 0.63-1.47), and Navy 0.56 (Cl: 0.43-0.74). Conclusion: Military deployment to GW1 was not a risk factor for developing MS. (C) 2014 S. Karger AG, Basel