This appendix includes a summary table of selected reports and studies that describe the burden of illness in the 1990-1991 Gulf War and OEF/OIF/OND veteran populations.
Summary of Selected Studies on Disease Burden
REPORTS/STUDY | VA UTILIZATION REPORTS IN 1990-1991 GULF WAR VETERANS (MS, migraine, PD, brain cancer) | VA UTILIZATION REPORTS IN OEF/OIF/OND VETERANS MS, migraine, PD, brain cancer) | SPECIFIC OUTCOMERELATED STUDIES (MS) | SPECIFIC OUTCOMERELATED STUDIES (headache and migraine) | SPECIFIC OUTCOMERELATED STUDIES (headache disorders) | SPECIFIC OUTCOMERELATED STUDIES (headache) | SPECIFIC OUTCOMERELATED STUDIES (cancer, including brain cancer) |
Authors | Department of Veterans Affairs (VA) | Department of Veterans Affairs (VA) | Wallin et al. (2014) | Kang et al. (2000) | Jankosky et al. (2011) | Theeler et al. (2012) | Young et al. (2010) |
Study Description |
Utilization reports of pre 9/11 veterans using the VA health system. Report based on ICD-9 codes for MS, migraine, PD, and malignant neoplasms of the brain. Provides counts for each diagnosis. Based on visits between October 1, 2001, and September 30, 2013. |
Utilization reports of post 9/11 veterans using the VA health system. Report based on ICD-9 codes for MS, migraine, PD, malignant neoplasms of the brain. Provides counts for each diagnosis. Based on visits between October 1, 2001, and September 30, 2014. |
Evaluated the risk of developing MS and other central nervous system demyelinating diseases (ODDs) in 1990-1991 Gulf War veterans. Cases of MS and ODD were matched to a DOD database of all active-duty personnel. All cases evaluated for service connection. |
Survey data used to report outcomes related to headaches and migraines in veterans of the 1990-1991 Gulf War. Self-reported responses were used to calculate weighted estimates of population rates for the conditions. |
Examined headache disorder in a large population-based US military cohort (using the Millennium Cohort)—a 21-year longitudinal study. Began in 2001 prior to OEF and OIF. | Designed to determine prevalence, characteristics, and factors associated with chronic daily headache. |
Studied cancer diagnoses in Gulf War era veterans. Using files from the DMDC and linked with 28 state cancer registries and the VA cancer registry. |
REPORTS/STUDY | VA UTILIZATION REPORTS IN 1990-1991 GULF WAR VETERANS (MS, migraine, PD, brain cancer) | VA UTILIZATION REPORTS IN OEF/OIF/OND VETERANS MS, migraine, PD, brain cancer) | SPECIFIC OUTCOMERELATED STUDIES (MS) | SPECIFIC OUTCOMERELATED STUDIES (headache and migraine) | SPECIFIC OUTCOMERELATED STUDIES (headache disorders) | SPECIFIC OUTCOMERELATED STUDIES (headache) | SPECIFIC OUTCOMERELATED STUDIES (cancer, including brain cancer) |
Number of Subjects | 286,995 deployed veterans | 1,126,173 OEF/OIF/OND veterans | 696,118 deployed Gulf War veterans | 15,000 Gulf War veterans | 38,361 combat deployed | 978 US Army | 621,902 deployed and 746,248 era Gulf War veterans |
Comparison Group | 269,635 nondeployed using VA health care services | None | 1,786,215 nondeployed veterans | 15,000 era veterans | Non-combat deployed | US population | Gulf War veterans and Gulf War era veterans |
Data Collection Methods | Provide counts for selected health care diagnoses for veterans using VA health care. | Provide counts for selected health care diagnoses for veterans using VA health care. |
An incident cohort of MS and ODD was assembled from Gulf War era veterans (1990-2007). Cases of MS and ODD were matched to a database of all active-duty personnel from DOD. |
Phase 1: 16-page structured questionnaire sent to each of the 30,000 veterans. Phase 2: telephone interviews on the nonrespondents. |
Baseline cohort: A random sample of 256,400 service members of the 2.2 million total serving as of October 1, 2000. Approximately 77,000 completed the baseline questionnaire; those with missing outcome data were excluded. |
Self-administered questionnaire | Review of DMDC, state cancer registries, and VA cancer registry |
REPORTS/STUDY | VA UTILIZATION REPORTS IN 1990-1991 GULF WAR VETERANS (MS, migraine, PD, brain cancer) | VA UTILIZATION REPORTS IN OEF/OIF/OND VETERANS MS, migraine, PD, brain cancer) | SPECIFIC OUTCOMERELATED STUDIES (MS) | SPECIFIC OUTCOMERELATED STUDIES (headache and migraine) | SPECIFIC OUTCOMERELATED STUDIES (headache disorders) | SPECIFIC OUTCOMERELATED STUDIES (headache) | SPECIFIC OUTCOMERELATED STUDIES (cancer, including brain cancer) |
Findings |
MS (ICD-9 340): deployed 1,040; nondeployed 1,089 Migraine (ICD-9 346): deployed 16,327; nondeployed 14,115 PD (IDC-9 332.0): deployed 403; nondeployed 487 Malignant neoplasm of the brain (ICD-9 191): deployed 342; nondeployed 332 |
MS (ICD-9 340): 1,529 deployed Migraine (ICD-9 346): 58,045 deployed PD (IDC-9 332.0): 322 deployed Malignant neoplasm of the brain (ICD-9 191): 458 deployed There are no data on the nondeployed |
For 1990-1991 Gulf War veterans: MS and ODD: 1,841 incident cases: 387 cases among the 696,118 deployed and 1,454 cases among the 1,786,215 nondeployed RR for MS 0.69 (95% CI: 0.61-0.78) |
Migraines: 16.5% of the deployed and 9.3% of the era veterans Recurring headaches 32.6% of deployed and 14.9% of the era veterans |
Combat deployed had statistically significantly higher adjusted odds of new-onset headache disorder than nondeployed (OR = 1.72, 95% CI 1.55-1.90 for men and OR = 1.84, 95% CI 1.55-2.18 for women). Those deployed without combat did not have statistically significantly different adjusted odds of new onset headaches compared to the nondeployed (OR = 1.07, 95% CI 0.95-1.21 for men; OR = 0.96, 95% CI 0.80-1.14 for women). |
Findings indicate that the prevalence of chronic daily headache is four to five times higher in OEF and OIF than the US population. Chronic daily headache following concussion often resembles chronic migraine and is associated with onset of headaches within the first week after concussion. |
Brain cancer: 278 in deployed and 410 in era Gulf War veterans. The PIR, comparing Gulf War deployed and era veterans: 0.86% (95% CI: 0.73-1.01). |
REPORTS/STUDY | VA UTILIZATION REPORTS IN 1990-1991 GULF WAR VETERANS (MS, migraine, PD, brain cancer) | VA UTILIZATION REPORTS IN OEF/OIF/OND VETERANS MS, migraine, PD, brain cancer) | SPECIFIC OUTCOMERELATED STUDIES (MS) | SPECIFIC OUTCOMERELATED STUDIES (headache and migraine) | SPECIFIC OUTCOMERELATED STUDIES (headache disorders) | SPECIFIC OUTCOMERELATED STUDIES (headache) | SPECIFIC OUTCOMERELATED STUDIES (cancer, including brain cancer) |
Strengths/Limitations |
Limited to those veterans using VA health care services. Captures approximately 46% of deployed, 36% of nondeployed. Based solely on a single entry of an ICD code for the disease of interest. |
Limited to those veterans using VA health care services. Captures approximately 60% of deployed. Based solely on a single entry of an ICD code for the disease of interest. |
Strengths include prospective study design, use of incident MS cases within the entire 1990-1991 Gulf War active-duty population; adequate power; and follow-up time to detect significant changes in MS risk in deployed troops. Limitations of the study: the possibility of missing some MS cases that may have had their first symptom outside the active-duty period and 7 years thereafter. |
A strength is the large number of subjects who were randomly selected. Limitations of this study include exposure and outcomes data are based on the selfreported data that may be subject to recall bias. The differential participation rate between Gulf War veterans and era veterans could contribute to a biased prevalence estimate. |
Strengths include the ability to estimate headache prevalence at baseline and new onset headache disorders at followup. Limitations include long postdeployment time frame; possible combat exposure misclassification; types of headaches not distinguished; inability to assess the lifetime prevalence of headache disorders at follow-up. |
Limitations include retrospective reporting of headaches, recall errors in reporting headache frequency, blast exposures, and symptoms of concussion. Screening for preexisting headaches was not performed. The study may not be representative of all US service members with a deployment-related concussion as it was conducted at a single US Army installation. |
Strengths include associating cancer incidence outcomes with the entire Gulf War veteran population; included a large and representative sample of era veterans. Outcome assessment based on cancer registry data rather than mortality, hospitalization, or self-reports. Limitations include lack of data from all 50 states and use of different registries may have resulted in slightly different match rates. |
NOTE: CI = confidence interval; DMDC = Defense Manpower Data Center; DOD = Department of Defense; ICD = International Classification of Diseases; MS = multiple sclerosis; ODD = other demyelinating disease; OEF = Operation Enduring Freedom; OIF = Operation Iraqi Freedom; OR = odds ratio; PD = Parkinson’s disease; PIR = Proportional Incidence Ratio; RR = relative risk; VA = Department of Veterans Affairs.
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