association between Gulf War deployment and hospitalization for fibromyalgia, but it should be noted that fibromyalgia is rarely severe enough to warrant hospitalization, so this finding can not be used to contradict that of Eisen et al. (2005).

Steele (2000) also found fibromyalgia in about 2% in Gulf War-deployed forces but had no nondeployed comparison group. Both the Iowa study and the Canadian study found significantly increased fibromyalgia symptoms in deployed Gulf War veterans than in nondeployed veterans, but the findings from these studies are limited because of the self-reporting of the diagnosis of fibromyalgia.

Two studies looked at the presence of fibromyalgia in veterans with PTSD. Amital et al. (2006) found that almost half the Israeli veterans with combat-related PTSD also had fibromyalgia, but the sample was small. Similar but less dramatic results were seen by Dobie et al. (2004), who found that female Gulf War veterans with PTSD were three times as likely to have fibromyalgia as those without PTSD.

The committee reviewed one primary study and three secondary studies on deployment-related stress and CWP. Although each of the studies found a higher prevalence of CWP in deployed than nondeployed veterans, all had considerable limitations. In Ang et al. (2006), the prevalence of CWP was found to increase both with increased combat exposure and with increased perception of life stress at the time of deployment; the study is limited in that only veterans with no pain 5 years after the conflict were evaluated 10 years after the conflict. The Stimpson et al. study (2006) also found an increase in CWP associated with deployment to a war zone. The other two secondary studies also showed more CWP in deployed than in nondeployed veterans. The committee reviewed one study of PTSD and CWP, which found a strong association between the two disorders (Ang et al. 2006).

Several studies have reviewed the presence of chronic pain in veterans but the definition of chronic pain varied with the study (Hyams et al. 1996; Kuzma and Black 2006; Thomas et al. 2006). Kuzma and Black (2006) noted that many studies of Gulf War veterans reported increased pain symptoms that could be clustered into CWP, but the terminology used in the studies was not consistent and included joint pain and general aches and pain; these pain clusters may or may not have met the ACR criteria for CWP.