veterans was compared more than 20 years after the war. Vital status as of 1991 was determined from VA beneficiary records, information from the Social Security Administration and the Internal Revenue Service, the National Death Index, and military personnel records; copies of official death certificates were used to determine cause of death. The Cox proportional-hazard multivariate regression model was used to derive cause-specific mortality risks for female Vietnam theater veterans vs female Vietnam-era veterans adjusted for rank, nursing status, duration of military service, and age at entry into followup. The RR for all cancer mortality was 1.00 (95% CI 0.75-1.34). The authors noted that there were increased risks of cancer of the pancreas, uterine corpus, brain, and other parts of the central nervous system in female Vietnam veterans, but the number of deaths was small and did not reach statistical significance, and adjustment for confounders was not possible. Female theater veterans had a lower mortality than female era veterans from lymphopoietic cancer and lung cancer. This study and that by Watanabe and Kang (1995) discussed above had the advantage of being conducted after a sufficient latent period for many cancers to be evident, however the number of cancer cases was small in each study, and their study populations were to small to have much potential to identify changes in the incidence of relatively rare cancers.
Not all cancers result in death, so a second study of the prevalence of gynecologic cancers among female Vietnam veterans was undertaken (Kang et al. 2000c). The prevalence of malignant tumors was ascertained in 4140 female Vietnam-theater veterans and 4140 female Vietnam-era veterans. Participants were given a structured health questionnaire via telephone interview, and self-reported gynecologic (breast, ovarian, uterine, or cervical) cancer was confirmed by review of medical or hospital records. The response rate of the 6430 women interviewed was 83-87%. A multivariate logistic model was used to calculate the ORs and 95% CIs. The adjusted OR was 1.14 (95% CI 0.94-1.40) for any gynecologic cancer; 1.18 (95% CI 0.91-1.51) for breast cancer, 1.83 (95% CI 0.72-4.61) for ovarian cancer, 1.00 (95% CI 0.61-1.61) for uterine cancer, and 1.11 (95% CI 0.74-1.66) for cervical cancer. Adjustments included age, race, branch of service, pay grade, marital status, nursing occupation, smoking, drinking, family history of cancer, use of birth-control pills, and postmenopausal estrogen and progestin use. Medical records were used to confirm self-reported cancer; 222 records were reviewed, and 99% of self-reported breast cancers, 76% of cervical cancers, 78% of ovarian cancers, and 61% of uterine cancers were confirmed. However, 10% of the self-reported cancers were not confirmed, and 5% of the medical records had no information on cancer. This study indicates that service in Vietnam did not increase the risk of gynecologic cancer in female Vietnam veterans. The study had a high response rate and relatively high validation rate for the diagnosis of gynecologic cancers that had a sufficient latent period for detection. It is limited by lack of information on possible exposures during service in Vietnam, including exposure to Agent Orange.
There was only one primary study in Gulf War-deployed veterans compared with their nondeployed counterparts, which indicated an increased risk of cancer. McCauley et al. (2002b) looked at cancer rates in Gulf War veterans residing in Oregon, Washington, California, Georgia, and North Carolina in 1999 as part of a larger study to assess neurologic and neurophysiologic signs and symptoms in veterans who may have been exposed to chemical-warfare agents as a result of the destruction of munitions at Khamisiyah, Iraq. Names of possible participants were obtained from the Defense Manpower Data Center (DMDC) maintained by the DoD. Gulf War-