US Gulf War Veterans: Service periods in theater, differential exposures, and persistent unexplained illness

Approximately 80000 of the 697000 American men and women who were stationed in SW Asia during the Gulf War (GW) report unexplained illness consisting of symptoms of persistent fatigue, cognitive difficulties, such as mild mem ory loss, diffuse muscle and joint pain, gastrointestinal symptoms, skin le sions, and respiratory problems, among others. Associations between major s ymptom groups and periods of deployment in the theater of operations have b een sought in a population-based, clinical case-control study of GW veteran s resident in the north-western region of the United States. No statistical ly significant differences were evident in the proportion of cases with une xplained fatigue, cognitive/psychological or musculoskeletal symptoms among veterans present in SW Asia in 3 specific time periods: (a) 8/1/1990-12/31 /1990 (which includes Desert Shield), (b) the period surrounding Desert Sto rm (1/1/1991-3/31/1991), and (c) the (post-combat) period immediately follo wing hostilities (4/1/1991-7/31/1991). There was a trend for all 3 case sym ptoms to be more common among GW veterans who served in the post-combat per iod. As numbers in these deployment groups were small, and power to detect differences low, the apparent absence of significant differences in the fre quency of major symptom groups among these veterans requires confirmation i n a larger study. Deployment for discrete periods in SW Asia is a method to separate distinct constellations of environmental factors; these are usefu l for analyses of associations among symptoms and exposures given the near- total absence of objective data on chemical and other possible exposures in the theater of operations. (C) 1998 Elsevier Science Ireland Ltd. All righ ts reserved.