Gulf War Troops, 1991 (IMAGE) Duke University Caption US Troops in the Persian Gulf War (1991). Gulf War Illness (GWI), which affects approximately 250,000 U.S. veterans, has been found to significantly reduce the ability of white blood cells to make energy and creates a measurable biochemical difference in veterans who have the disease. Credit US Department of Defense Usage Restrictions No restrictions. License Public Domain Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.