HOSPITALIZATIONS FOR UNEXPLAINED ILLNESSES AMONG US VETERANS OF THE PERSIAN-GULF-WAR

Persian Gulf War veterans have reported a variety of symptoms, many of which have not led to conventional diagnoses. We ascertained all acti ve-duty U.S. military personnel deployed to the Persian Gulf War (552, 111) and all Gulf War era military personnel not deployed (1,479,751) and compared their postwar hospitalization records (until 1 April 1996 ) for one or more of 77 diagnoses under the International Classificati on of Diseases (ICD-9) system. The diagnoses were assembled by the Eme rging Infections Program, Centers for Disease Control and Prevention, and are here termed ''unexplained illnesses.'' Deployed veterans were found to have a slightly higher risk of hospitalization for unexplaine d illness than the nondeployed. Most of the excess hospitalizations fo r the deployed were due to the diagnosis ''illness of unknown cause'' (ICD-9 code 799.9), and most occurred in participants of the Comprehen sive Clinical Evaluation Program who were admitted for evaluation only . When the effect of participation in this program was removed, the de ployed had a slightly lower risk than the nondeployed. These findings suggest that active-duty Gulf War veterans did not have excess unexpla ined illnesses resulting in hospitalization in the 4.67-year period fo llowing deployment.