摘要：Objectives. We identify symptom patterns among veterans who believe they suffer from Gulf War–related illnesses and characterize groups of individuals with similar patterns. Methods. A mail survey was completed by 1161 veterans drawn from the Gulf War Health Registry. Results. An exploratory factor analysis revealed 4 symptom factors. A K-means cluster analysis revealed 2 groups: (1) veterans reporting good health and few moderate/severe symptoms, and (2) veterans reporting fair/poor health and endorsing an average of 37 symptoms, 75% as moderate/severe. Those in Cluster 2 were more likely to report having 1 or more of 24 medical conditions. Conclusions. These findings are consistent with previous investigations of symptom patterns in Gulf War veterans. This multisymptom illness may be more fully characterized by the extent, breadth, and severity of symptoms reported. Nearly 697 000 US service personnel served in Operations Desert Shield and Desert Storm in 1990 and 1991. During the war, casualties among these troops were extraordinarily low. Yet, after the war, many returning veterans complained about persistent, unexplained health problems. 1– 3 Significant controversy erupted concerning the existence, extent, and etiology of what has come to be called “Gulf War syndrome,” or more broadly, “Gulf War–related illnesses.” In response to the controversy, Congress required that the Department of Veterans Affairs (VA) hospitals offer all Gulf War veterans, who volunteered to be examined, complete physical examinations including appropriate diagnostic tests and referrals. Portions of the resulting information were stored in a database, commonly called the Gulf War Health Registry. More than 70 000 veterans have entered the registry since its inception in 1992. Not all the veterans in the registry believe themselves to be currently ill as the result of Gulf War service. However, the registry represents the largest group of veterans who believe they may have Gulf War–related illnesses; the registry therefore is an excellent resource to further investigate the phenomenon of Gulf War–related illnesses. In contrast to prior studies that included veterans both in and not in the registry, this investigation of registry veterans identifies patterns of symptoms specifically among veterans who believe they have been made ill as the result of service in the Gulf War. It also takes the logical next step of attempting to characterize cases by identifying specific groups of individuals who share similar patterns of symptoms, and identifying associated demographic, medical history, and other risk factors for membership in those groups. Some previous attempts at characterizing Gulf War–related illnesses have examined symptom patterns endorsed by small numbers of presumed cases within a single unit 4 or single branch of service. 5 One of these studies, supported by the US Centers for Disease Control and Prevention (CDC), studied 3723 deployed and nondeployed Air Force troops from 4 units. 6 The respondents indicated the presence, duration, and severity of symptoms. Classification of cases using both clinical epidemiological and factor analysis approaches, defined by the Centers for Disease Control and Prevention, were consistent with an illness definition of 1 or more chronic symptoms from at least 2 of 3 symptom categories related to fatigue, mood/cognition, and musculoskeletal symptoms. Deployment to the Gulf War was found to be the most important risk factor for this multisymptom illness. As part of our investigation, we examine the applicability of the CDC’s definition of multisymptom illness in classifying ill veterans in our sample from the registry. Other studies have attempted to compare the distribution and patterns of symptoms within large groups of deployed and nondeployed groups of veterans. 1, 5, 7– 10 In each of these comparative studies, Gulf War veterans reported a greater prevalence of symptoms across body systems, but several of the studies concluded that the patterns of symptoms reported by Gulf War veterans did not suggest illnesses distinct from those in the general population. 5, 7– 10 Yet, there is good reason to validate this conclusion in a cohort including a large number of presumed cases. If unique Gulf War–related illnesses do exist, it is unclear how many cases might be captured within any random sample of deployed veterans. If the number of cases is relatively small, any distinct patterns of symptoms characteristic of those cases might be obscured by the larger distribution of symptoms reported by veterans experiencing the normal range of health problems expected in any large population. By examining a sample presumably containing a large number of cases, any underlying pattern of symptoms common to Gulf War–related illnesses would more likely emerge.
