Brief Life Stress Questionnaire) at the time of the Gulf War, whether military-related or not (OR 1.4, 95% CI 1.0-2.0), and with perceived life stress in the 6 months after returning home (OR 1.3, 95% CI 1.0-1.8). CWP also correlated with combat exposure during deployment (OR 1.5, 95% CI 1.1-2.0) although not specifically with deployment to the gulf itself (OR 1.1, 95% CI 0.6-2.0). Symptoms of alcohol use at the 5-year baseline survey were protective for CWP at 10 years (OR 0.2, 95% CI 0.1-0.6, p = 0.0039). The authors used the Expanded Combat Exposure Scale in the baseline survey and reported that for every 5-point increase in combat exposure score, there was a 50% increase in the likelihood that a veteran would develop CWP. Although the study had the advantage of using an in-person evaluation for the medical diagnosis of CWP and had a relatively large population of deployed and nondeployed veterans, there was a possibility of recall bias for life and deployment stressors reported 5 years after the conflict, and only veterans from Iowa were evaluated. Furthermore, only veterans who did not meet the CWP criteria at baseline were considered for the followup evaluation; veterans who may have developed CWP during the first 5 years after the conflict were not included in the followup examination.
Several studies have looked at self-reports of fibromyalgia, symptoms of fibromyalgia, or CWP in Gulf War veterans. The Iowa Persian Gulf Study Group (1997) surveyed 1896 Gulf War-deployed and 1799 nondeployed veterans who listed Iowa as their home state at the time of enlistment to determine whether there was a unique Gulf War illness. In telephone interviews, veterans were asked about symptoms of fibromyalgia on the basis of questions keyed to the symptom criteria of Wolfe et al. (1990), which included the presence of widespread pain for at least 3 months. Symptoms of fibromyalgia were present in 18.2% of 985 deployed regular military veterans and 23.8% of 911 deployed National Guard or reserve veterans compared with 9.2% of 968 nondeployed regular military veterans and 13.2% of 831 nondeployed National Guard or reserve veterans. The authors found a statistically significant Cochran-Mantel-Haenszel rate difference of 9.3 (95% CI 7.3-11.2) after adjustment for age, sex, race, branch of military, and rank. Although the study used a large population-based sample, the determination of fibromyalgia was based solely on self-reported symptoms, not a physical examination. Participants were asked about a number of military exposures during deployment, including chemical and psychologic stressors, although combat was not specifically mentioned. The study had a high response rate: interviews were completed with 78% of the eligible deployed veterans and 73% of the eligible nondeployed veterans.
In a similar study conducted by Steele (2000), 1545 deployed and 435 nondeployed Gulf War veterans who were residents of Kansas in 1998 were asked about their health status in telephone interviews. Specifically, they were asked whether they had ever received a physician’s diagnosis of or treatment for fibromyalgia and, if so, when it had developed. Of the deployed and nondeployed veterans, 2% (n = 24) and less than 0.5% (n = 2), respectively, reported having a diagnosis of fibromyalgia with new onset between 1990 and 1998 (OR 3.69, 95% CI 0.86-15.84 adjusted for sex, age, income, and education level). Although the study included a population-based sample, its goal was to ascertain the prevalence of symptoms that might be indicative of Gulf War illness and the circumstances that increased their prevalence. No physical examinations were conducted to confirm a diagnosis of fibromyalgia or to link it to specific exposures.