administered to 602 individuals who previously met the criteria for one or more of the following: depression, chronic widespread pain, and cognitive dysfunction. The overall response rate was 95.7% (n = 576). See Chapter 4 for further detail.
Three reference studies of UK Gulf War veterans were identified in Volume 4: Cherry et al. (2001a,b); Maconochie et al. (2003); and Unwin et al. (1999). Two teams of researchers in the UK studied separate, nonoverlapping, stratified random samples of the over 53,000 military personnel sent to the Gulf War. The first team was from the University of London (Guy’s, King’s, and St. Thomas Medical Schools); the second team was from the University of Manchester. In addition, a third team of researchers from the London School of Hygiene and Tropical Medicine surveyed the entire cohort of 53,000 veterans examining birth defects and other reproductive outcomes. The Update committee identified only one new derivative study which was based on the University of London cohort study.
At the University of London, Unwin and colleagues (1999) studied the health effects of deployment by randomly sampling the entire UK contingent deployed to the Gulf War (n = 53,462)4; the control groups consisted of those deployed to the conflict in Bosnia (n = 39,217) and servicemembers who were deployed in the same period to noncombat locations outside the United Kingdom (n = 250,000). The nondeployed control group was recruited from among the subset of nondeployed servicemembers who were fit for combat duty, thus avoiding selection bias related to the healthy warrior effect. Investigators distributed a mailed questionnaire that asked about symptoms (50 items), medical disorders (39 items), exposure history (29 items), functional capacity, and other topics. Potential confounding factors (including sociodemographic and lifestyle factors) were controlled for in multiple logistic regression analysis. Response rates were as follows: 70.4% Gulf War deployed; 61.9% Bosnia cohort; and 62.9% era cohort. The Gulf War deployed veterans reported a higher prevalence of symptoms and diminished functioning than did either comparison group.
The two UK Gulf War cohorts completed a second questionnaire with details of the dates they were deployed to each location and the exposures they had experienced. The questionnaire listed 14 exposures, such as combat exposure, number of inoculations, number of days handling pesticides, days exposed to smoke from oil fires, and duration of stay in the gulf. The main analysis involved a multiple regression of each of the seven factors identified through factor analysis on all exposures and other potential confounders. Many of the reported exposures correlated with one another. In the multivariate regression analysis, the number of days veterans handled pesticides was related to the overall severity score and to the peripheral and neurologic factors; the number of days they applied insecticide to their skin was related to severity and to the peripheral, respiratory, and appetite factors. The number of inoculations was associated with skin and musculoskeletal symptoms. Further results are discussed in detail in Chapter 4.