groups for a nonsignificant OR of 1.22 (95% CI 0.45-3.30) adjusted for sex, age, income, and education level.
Simmons et al. (2004) surveyed all 51,581 male UK veterans who served in the Gulf War and a demographically similar comparison cohort of 51,688 UK male veterans who were not deployed to the gulf. Among the 23,358 deployed men who responded, 0.2% reported having diabetes with onset after 1990, as did 0.4% of 17,730 nondeployed men who responded, for a nonsignificant OR of 0.7 (95% CI 0.5-1.0) adjusted for age at the time of the survey, service and rank at the time of the Gulf War, serving status at the time of the survey, alcohol consumption, and smoking.
Kang et al. (2000b) conducted a mail and telephone survey to assess the health status of a stratified random sample of Gulf War-deployed veterans compared with veterans who were in the military at the time of the Gulf War but were not deployed to the region. On the basis of 15,817 mail responses and 5,100 telephone responses of self-reports of medical conditions during the preceding 12 months, the authors estimated the population prevalence of diabetes to be 0.8% in Gulf War veterans and 0.9% in Gulf War-era veterans (significant decreased rate difference −0.08, 95% CI −0.11 to −0.05). The authors further estimated that 1.7% of the deployed veterans and 1.5% of the nondeployed veterans had some other endocrine disorder (statistically significant increased rate difference 0.2, 95% CI 0.16-0.24). The response rate in the study was 70%.
Only one primary study looked at endocrine function in Vietnam veterans. The VES (CDC 1988b) discussed above also assessed thyroid-hormone concentrations in deployed and nondeployed Vietnam veterans 15-20 years after the war. Deployed and nondeployed veterans had the same mean TSH concentration (1.6 mU/L) and the same mean free-thyroxine (free-T4) index (2.2). Of the deployed veterans, 1% had TSH outside the reference range (reference range defined as ≤ 10 mU/L for both cohorts combined) compared with 0.6% of the nondeployed veterans for an OR of 2.0 (95% CI 0.9-4.3); 5.4% of the deployed veterans were outside the reference range of the free-triiodothyronine (T3) index (≥ the fifth percentile for the combined cohorts) compared with 4.6% of the nondeployed vets for an OR of 1.2 (95% CI 0.9-1.5). The ORs were adjusted for age at enlistment, race, year of enlistment, enlistment status, score on general technical test, and primary military occupational specialty.
In the Eisen et al. study (2005) discussed above, thyroid function was assessed in the Gulf War-deployed and nondeployed veterans. Hypothyroidism was defined as an untreated TSH concentration of 10.0 mU/mL or greater or as taking medication for hypothyroidism. Hyperthyroidism required an untreated TSH concentration of less than 0.1 mU/mL or as taking medication for hyperthyroidism. Of the deployed Gulf War veterans, 1.6% had hypothyroidism compared with 1.2% of nondeployed veterans for a nonsignificant OR of 1.70 (95% CI 0.75-3.87, p = 0.2) adjusted for age, sex, race, cigarette-smoking, duty type, service branch, and rank. Of the deployed veterans, 0.3% had hyperthyroidism compared with 0.1% of the nondeployed veterans for a nonsignificant OR of 4.86 (95% CI 0.68-34.58, p = 0.11) adjusted for age, sex, race, cigarette-smoking, years of education, and duty type.
Two retrospective cohort studies by Gray et al. (1996, 2000) looked at hospitalizations of Gulf War veterans for “endocrine, nutritional, and metabolic diseases” (ICD-10 E00-E99). In the