The U.K. Study

Unwin and collaborators (1999) investigated the health of servicemen from the United Kingdom in a population-based study. This study is especially useful because the researchers conducted a random sample of the entire U.K. contingent of about 53,000 personnel deployed to the Persian Gulf12 and used two comparison groups. One of the comparison groups was deployed to the conflict in Bosnia (n = 4,250), making this study the only one to use a comparison population with combat experience during the time of the Gulf War. The second comparison group was deployed to other noncombat locations outside the United Kingdom over the same time frame (n = 4,246). Through a mailed questionnaire, the investigators asked about symptoms (50 items), medical disorders (39 items), and functional capacity, among other topics. The findings for the Gulf War cohort and comparison cohorts were compared through calculation of odds ratios. The study controlled for potential confounding factors (including sociodemographic and life-style factors) by logistic regression analysis. Only male veterans’ results were analyzed, however, because female veterans’ roles and symptoms were distinct enough to warrant separate consideration.

The U.K. Gulf War-deployed veterans (n = 4,248) reported higher prevalence of symptoms and diminished functioning than did both comparison groups. Gulf War veterans were two to three times more likely than comparison subjects to have met symptom-based criteria for chronic fatigue, posttraumatic stress reaction, and “chronic multisymptom illness” (the label for the first case definition13 developed by Centers for Disease Control and Prevention [CDC] researchers to probe for the existence of a potentially new syndrome among Gulf War veterans) (Fukuda et al., 1998). That the Bosnia cohort in the U.K. study, which was deployed to a combat setting, reported fewer symptoms than the Gulf War cohort, suggests that combat deployment per se does not account for higher symptom reporting.

Symptom clustering. In a companion study using the U.K. data set, Ismail and colleagues (1999) set out to determine whether the symptoms that occurred with heightened prevalence in U.K. Gulf War veterans constitute a new syndrome. By applying factor analysis, the researchers were able to identify three fundamental factors, which they classified as mood, respiratory system, and peripheral nervous system, according to the types of symptoms that contributed to each factor. The pattern of symptom reporting by Gulf War veterans differed little from the patterns of Bosnia and Gulf War era comparison groups,

12  

U.K. military personnel in the Gulf War were somewhat different from U.S. personnel in terms of demographics, combat experience, and exposures to certain agents (U.K. Ministry of Defense, 2000).

13  

A case is defined as having one or more chronic symptoms from at least two of these three categories: fatigue, mood–cognition (e.g., feeling depressed, difficulty remembering or concentrating), and musculoskeletal (joint pain, joint stiffness, or muscle pain). This case definition was developed as a research tool in order to organize veterans’ unexplained symptoms into a potentially new syndrome, as explained elsewhere in this section.



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