Air Force Study

Various members of a Pennsylvania Air National Guard unit reported illnesses potentially associated with their previous deployment to the Gulf War. In November 1994, the Pennsylvania State Health Department, the U.S. Department of Veteran Affairs, and the U.S. Department of Defense requested that CDC conduct an independent investigation of those illnesses. The investigation, carried out by CDC’s National Center for Infectious Diseases, involved three phases:

  1. interviews with and examination of ill Gulf War veterans from the Air National Guard unit (the index unit) and review of medical records to verify and characterize illness;
  2. a survey of 3,723 military personnel from four Air Force units, including veterans who were and were not deployed to the Gulf War, to determine the relative prevalence of symptoms and to develop a working case definition of illness; and
  3. a clinical evaluation of 158 Gulf War veterans from the index unit to further clinically characterize illness and to identify risk factors (by examination and laboratory tests).

A case was defined as a person having one or more chronic symptoms from at least two of three symptom categories (fatigue, mood-cognition, and musculoskeletal). A case was further classified as severe if each case-defining symptom was rated as severe; otherwise, the case was classified as mild-to-moderate. Cases were more likely to demonstrate poorer functioning, depression, and post-traumatic stress disorder. However, no consistent abnormalities were found by physical examination, routine laboratory tests, or tests for several infectious agents endemic to the Middle East. The prevalence of mild-to-moderate and severe cases was 39% and 6%, respectively, among Gulf War veterans versus 14% and 0.7% among nondeployed veterans. Fifty-nine (37%) clinically evaluated Gulf War veterans did not qualify as cases, 86 (54%) were mild-to-moderate cases, and 13 (8%) were severe cases. The investigators identified a chronic multisystem condition that was significantly associated with deployment to the Gulf War, but was not associated with specific Gulf War exposures, and that also affected nondeployed personnel.


Centers for Disease Control and Prevention. Unexplained illness among Persian Gulf War veterans in an Air National Guard unit: August 1990-March 1995. Morbidity and Mortality Weekly Report 1995;44:443–7.

Fukuda K, Nisenbaum R, Stewart G, Thompson WW, Robin L, Washko RM, et al. Chronic multisymptom illness affecting Air Force veterans of the Gulf War. Journal of the American Medical Association 1998;280:981–8.

Nisenbaum R, Barrett DH, Reyes M, Reeves WC. Deployment stressors and a chronic multisymptom illness among Gulf War veterans. Journal of Nervous and Mental Disorders 2000;188:259–66.

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Page last reviewed: October 29, 2010 (archived document)