rized in Chapter 2 also furnished evidence of overlapping symptomatology. In the Iowa study, symptoms of fibromyalgia were reported by 19.2 percent of Gulf War veterans versus 9.6 percent of nondeployed controls. Symptoms of chronic fatigue were reported by 1.3 percent of veterans versus 0.3 percent of controls (Table 2.3).¹⁵ Both findings were statistically significant (Iowa Persian Gulf Study Group, 1997). Similarly, in the study of Canadian forces sent to the Persian Gulf, symptoms of multiple chemical sensitivity, fibromyalgia, and chronic fatigue were significantly elevated in veterans relative to controls (Goss Gilroy, 1998). Finally, the study of U.K. veterans revealed symptoms of chronic fatigue syndrome to have been significantly heightened in Gulf War veterans in relation to Bosnia and Gulf era controls (3.3 percent in veterans versus 0.8 percent in both control groups) (Unwin et al., 1999). These three population-based studies were methodologically strong, based on either a random sample of the Gulf War veteran population (Iowa,¹⁶ United Kingdom) or the entire Gulf War veteran population (Canada). Each study used veterans not deployed to the Persian Gulf for comparison purposes.

A questionnaire study of 1,935 veterans randomly sampled from the VA registry found 15.7 percent to qualify for chronic fatigue syndrome and 13.1 percent to qualify for multiple chemical sensitivity (Kipen et al., 1999). Smaller studies have focused on symptoms of chemical sensitivity in Gulf War veterans. In a pilot study of 48 veterans, Bell and colleagues (1998b) found that 12 out of 14 (86 percent) veterans reporting poorer global health status described themselves in a questionnaire as currently being chemically sensitive (in contrast to healthy Gulf War veterans and two other control groups of Gulf era veterans). Using a newly validated questionnaire to measure chemical sensitivity, Miller and Prihoda (1999) compared Gulf War veterans (n = 72), implant recipients (n = 89), individuals with multiple chemical sensitivity (n = 186) and healthy controls (n = 76). Chemical intolerance and symptom severity scores were significantly greater for all three groups than for controls.

The only published study thus far to have examined Gulf War veterans expressly for a diagnosis of multiple chemical sensitivity, as well as for chronic fatigue syndrome and fibromyalgia, was undertaken by Pollet and coworkers (1998). They performed physical examinations on 53 veterans who had volunteered for the VA registry with complaints of fatigue or chemical sensitivity. Of this group, 33 (62 percent) met diagnostic criteria for chronic fatigue syndrome, 20 for multiple chemical sensitivity, and 3 for fibromyalgia.¹⁷ When compared