Gulf War Veterans' Health: Medical Evaluation of a U.S. Cohort

Context The prevalence and association of medical conditions with deployment to the 1991 Gulf War are controversial. Contribution This cross-sectional study, performed 10 years after the 1991 Gulf War, compared the prevalence of 12 conditions between 1061 deployed and 1128 nondeployed U.S. veterans. Only fibromyalgia (2% vs. 1.2%), the chronic fatigue syndrome (1.6% vs. 0.1%), skin conditions (34.6% vs. 26.8%), and dyspepsia (9.1% vs. 6.0%) were more common among deployed veterans. Cautions Short-term conditions that resolved weren't assessed. Fifty-three percent of deployed eligible veterans and 39% of nondeployed eligible veterans participated in the study. Implications Only a few health conditions seem to be associated with Gulf War deployment. The Editors Approximately 700000 U.S. servicemen and servicewomen were deployed to the Persian Gulf during the 1991 Gulf War. Although only 200 U.S. combat-related deaths occurred, many personnel were subjected to various natural and man-made environmental exposures, including sand flies, molds, infectious agents, vaccines, medical prophylaxis, pesticides, depleted uranium, oil-fire smoke, biological and chemical warfare agents, and psychological stress (1). Within months of their return, many ground-deployed personnel began reporting fatigue, skin rashes, bone and joint pains, symptoms suggestive of the irritable bowel syndrome, cognitive dysfunction, emotional distress, and other symptoms (2-5). Questionnaire surveys of U.S. (6), British (7), and Canadian (8) veterans and more representative veteran cohorts selected from Iowa (9), New England (10), the U.S. Air Force (11), and Great Britain (12) supported individual reports. In 1995, the U.S. Department of Veterans Affairs funded the National Health Survey of Gulf War Era Veterans and Their Families research project. This study, which compared the health of 15000 deployed veterans with 15000 nondeployed veterans through mail and telephone surveys, found that deployed veterans reported a higher prevalence of 29 of 31 self-reported medical conditions and 48 symptoms than nondeployed veterans (13). In our study, we recruited a subset of deployed and nondeployed veterans who participated in the National Health Survey of Gulf War Era Veterans and Their Families for a medical evaluation to assess and compare the long-term prevalence of selected medical conditions in a national cohort of deployed and nondeployed Gulf War veterans. Methods Study Population and Recruitment Recruitment for the National Health Survey of Gulf War Era Veterans and Their Families study has been described elsewhere in detail (13) and is summarized in the Figure. Briefly, the U.S. Department of Defense's Defense Manpower Data Center, Monterey, California, identified the entire cohort of 693826 troops who were deployed to the Persian Gulf area during the Gulf War and approximately half (800 680 troops) of the nondeployed troops who were in military service between September 1990 and May 1991. A total of 15000 deployed and 15000 nondeployed veterans were solicited to participate in the study. To ensure that women, reservists, and National Guard members were adequately represented, the investigators applied a stratified random sampling method to each group so that one fifth of each sample were women (n= 3000), one third were reservists (n= 5000), and approximately one quarter were members of the National Guard (n= 4000). Figure. Sample selection flowchart. For our study, we created a list of potential participants by randomly selecting from the 11441 deployed and 9476 nondeployed Gulf War veterans who participated in the 1995 study, stratified by deployment status (deployed or not deployed) and region of last known residence at the time of the original survey based on home telephone area code (Figure). We assigned potential participants to the participating Veterans Affairs medical center closest to their home residence. Participating medical centers were in Albuquerque, New Mexico; Baltimore, Maryland; Birmingham, Alabama; Boston, Massachusetts; Cincinnati, Ohio; Hines (Chicago), Illinois; Houston, Texas; Miami, Florida; Minneapolis, Minnesota; New Orleans, Louisiana; New York, New York; Portland, Oregon; Richmond, Virginia; Salt Lake City, Utah; San Diego, California; and St. Louis, Missouri. We gave each member of the cohort assigned to a medical center a randomly generated number, and the numbers were sequenced in ascending order. We performed 3 recruitment waves of approximately 40 deployed and 40 nondeployed veterans at approximately 8-month intervals at each site, beginning with the veteran who was assigned the lowest number. In each wave, the veteran received a recruitment package that included an introductory letter, a detailed explanation of the purpose and nature of the study, a letter of intent form, and a preaddressed and stamped return envelope. We asked potential veteran participants to sign and return the letter of intent to participate in the study. Veterans who did not respond within a few weeks received a reminder call. To further encourage study participation, we sent nonrespondents a newsletter and a 12-minute videotape that presented a typical clinical examination day and several testimonies of veterans who had already completed the study. Two research contractors (Gallup Organization, Omaha, Nebraska, for the first wave, and Schulman, Ronca & Bucuvalas, Inc., Silver Spring, Maryland, for successive waves) mailed recruitment packages and made reminder follow-up calls. Because of lower participation rates among nondeployed veterans, we solicited an additional 799 nondeployed veterans to obtain groups of equal size. The signed letter of intent was returned to the Hines Veterans Affairs Cooperative Studies Program Coordinating Center, Hines, Illinois, which forwarded it to the participating Veterans Affairs medical center to which the veteran was assigned. Site personnel then contacted the veteran and scheduled the examination. The research project provided travel, hotel, and per diem costs and an honorarium of $200. The Hines Cooperative Studies Program Human Rights Committee and the institutional review board at each individual site approved the protocol and consent form. Participants gave signed informed consent shortly before the start of the examination. Data Collection To assess nonparticipation bias, we obtained previously collected data from deployed and nondeployed participants and nonparticipants, including sociodemographic and military service characteristics in 1991 from the U.S. Department of Defense's Defense Manpower Data Center and sociodemographic and self-reported health data collected by the National Health Survey of Gulf War Era Veterans and Their Families in 1995. For our study, physicians and research nurses performed medical, neurologic, gynecologic, and psychiatric histories and examinations between 1999 and 2001 by using carefully standardized methods. A research nurse solicited histories of symptoms and illnesses in 8 system categories by using a structured interview. Examinations were followed by laboratory, pulmonary function, nerve conduction, and neuropsychological tests. The average examination time was 12 hours performed over 2 days. In this paper, we report the study's medical outcomes. Other manuscripts will address the psychiatric and neuropsychological results. Disease Diagnostic Criteria Fibromyalgia The diagnosis of fibromyalgia followed the 1990 American College of Rheumatology criteria of diffuse body pain and pain on physical examination on at least 11 of 18 tender points (14). The Chronic Fatigue Syndrome The diagnosis of the chronic fatigue syndrome followed the International Chronic Fatigue Syndrome Study Group case definition (15). After data collection was complete, 4 physicians and a psychologist, who were blinded to the participants' deployment status, reviewed medical and psychiatric data on individuals who met the chronic fatigue syndrome inclusion criteria. We identified exclusionary psychiatric disorders by participant responses to the Composite International Diagnostic Interview (CIDI) (16) and self-reported psychiatric diagnoses. We determined exclusionary medical illnesses from history, examination, self-reported diagnoses, and laboratory testing. Peripheral Neuropathy The diagnosis of peripheral neuropathy included any idiopathic or unexplained distal sensory, motor, or sensorimotor polyneuropathy based on physical findings, nerve conduction studies, or both. Upper motor neuron findings, alcohol abuse or dependence, HIV or AIDS, hypothyroidism, diabetes, or antineoplastic medications excluded this diagnosis. Self-Reported Physical HealthRelated Quality of Life We used the physical component score of the Medical Outcomes Study Short Form-36 (SF-36) (17) to provide an overall measure of current self-reported physical healthrelated quality of life. For the average healthy population, the physical component score was a mean of 50, SD 10. Dermatologic Conditions We divided dermatologic conditions a priori into 2 groups. Group 1 conditions were freckles, lentigines, seborrheic keratoses, nevi, moles, cherry hemangiomas, skin tags, and surgical scars detected by research physicians after full-body skin examinations. Group 2 skin diagnoses included all diagnoses that are not included in group 1. A board-certified dermatologist diagnosed these conditions by using teledermatology, at least 2 digital photographs, and the results of a standardized history and physical examination. Other Illnesses Dyspepsia criteria included a history or symptoms of dyspepsia (frequent heartburn and recurrent abdominal pain) and use of antacids, H2-blockers, or other medications to treat dyspepsia. Hypertension was defined as blood pressure greater than 140/90 mm Hg or history of hypertension and use of antihypertensive medications. Hepatitis was defined as an alanine aminotransferase level greater than 1