Many of the symptoms of Gulf War illness are similar to the symptoms of organophosphate,
mustard gas, and
nerve gas poisoning. Gulf War veterans were exposed to a number of sources of these compounds, including nerve gas and
pesticides. In 2022, researchers led by Robert Haley, MD at
University of Texas Southwestern Medical Center found that exposure to sarin nerve gas in soldiers who had a particular genetic mutation that prevented them from breaking down the nerve gas is likely to be responsible for the syndrome. In addition to the many physical and psychological issues involved in any war zone deployment, Gulf War veterans were exposed to a unique mix of hazards not previously experienced during wartime. These included
pyridostigmine bromide pills (given to protect troops from the effects of nerve agents), depleted uranium munitions, and multiple simultaneous vaccinations including
anthrax and
botulinum toxin vaccines. The oil and smoke that spewed for months from hundreds of burning oil wells presented another exposure hazard not previously encountered in a war zone. Military personnel also had to cope with swarms of insects, requiring the widespread use of pesticides. High-powered microwaves were used to disrupt Iraqi communications, and though it is unknown whether this might have contributed to the syndrome, research has suggested that safety limits for electromagnetic radiation are too lenient. The Research Advisory Committee on Gulf War Veterans' Illnesses (RAC), a VA federal advisory committee mandated by Congress in legislation enacted in 1998, The RAC concluded However, in 1997, the US Government released an unclassified report that stated: : "The
US Intelligence Community (IC) has assessed that Iraq did not use chemical weapons during the Gulf war. However, based on a comprehensive review of intelligence information and relevant information made available by the United Nations Special Commission (UNSCOM), we conclude that chemical warfare (CW) agent was released as a result of US postwar demolition of rockets with chemical warheads in a bunker (called Bunker 73 by Iraq) and a pit in an area known as
Khamisiyah." Over 125,000 U.S. troops and 9,000 U.K. troops were exposed to nerve gas and
mustard gas when the Iraqi depot in Khamisiyah was destroyed. Studies have confirmed earlier suspicions that exposure to sarin, in combination with other contaminants such as pesticides and PB were related to reports of veteran illness. Estimates range from 100,000 to 300,000 individuals exposed to nerve agents. The 2014 report by the U.S. Department of Veterans Affairs (VA) Research Advisory Committee on Gulf War illnesses (RAC) concluded that, "exposure to the nerve gas agents sarin/cyclosarin has been linked in two more studies to changes in structural magnetic resonance imaging findings that are associated with cognitive decrements, further supporting the conclusion from evidence reviewed in the 2008 report that exposure to these agents is etiologically important to the central nervous system dysfunction that occurs in some subsets of Gulf War veterans."
Earlier considered potential causes Depleted uranium The Gulf War included the first widespread combat usage of
depleted uranium (DU), in tank
kinetic energy penetrator and
autocannon rounds. DU has been suggested as a possible cause of Gulf War syndrome. A 2008 review by the U.S. Department of Veterans Affairs found no association between DU exposure and multisymptom illness, concluding that "exposure to DU munitions is not likely a primary cause of Gulf War illness". There is some evidence that long-term exposure to high doses of DU can cause other health problems that are unrelated to GWS. The
Veterans Administration decides these claims on a case-by-case basis. A 2018 study stated that "the number of Gulf War veterans who developed the Gulf War syndrome following exposure to high quantities of DU has risen to about one-third of the 800,000 U.S. forces deployed", with 25,000 of those having had a premature death. A 2021 study by a team at the
University of Portsmouth tested urine samples of 154 US veterans, reporting that no soldiers with the syndrome were exposed to significant amounts of depleted uranium and that DU "is not and never was in the bodies of those who are ill at sufficient quantities to cause disease".
Pyridostigmine bromide nerve gas antidote The US military issued
pyridostigmine bromide (PB) pills to protect against exposure to nerve gas agents such as sarin and
soman. PB was used as a
prophylactic against nerve agents; it is not a vaccine. Taken before exposure to nerve agents, PB was thought to increase the efficiency of nerve agent antidotes. PB had been used since 1955 for patients who have
myasthenia gravis with doses up to 1,500 mg a day, far in excess of the 90 mg given to soldiers, and was considered safe by the FDA at either level for indefinite use and its use to pre-treat nerve agent exposure had recently been approved. Given both the large body of epidemiological data on myasthenia gravis patients and follow-up studies done on veterans, it was concluded that while it was unlikely that health effects reported today by Gulf War veterans are the result of exposure solely to PB, use of PB was
causally associated with illness.
Organophosphates Organophosphate-induced delayed neuropathy (OPIDN, aka organophosphate-induced delayed polyneuropathy) may contribute to the unexplained illnesses of the Gulf War veterans.
Organophosphate pesticides The use of
organophosphate pesticides and
insect repellents during the first Gulf War is credited with keeping rates of pest-borne diseases low. Pesticide use is one of only two exposures consistently identified by Gulf War epidemiologic studies to be significantly associated with Gulf War illness. Multisymptom illness profiles similar to Gulf War illness have been associated with low-level pesticide exposures in other human populations. In addition, Gulf War studies have identified dose-response effects, indicating that greater pesticide use is more strongly associated with Gulf War illness than more limited use. Pesticide use during the Gulf War has also been associated with
neurocognitive deficits and
neuroendocrine alterations in Gulf War veterans in clinical studies conducted following the end of the war. The 2008 report concluded that "all available sources of evidence combine to support a consistent and compelling case that pesticide use during the Gulf War is causally associated with Gulf War illness." The VA's 2014 RAC report reinforced its 2008 report findings: "The research reviewed in this report supports and reinforces the conclusion in the 2008 RACGWVI report that exposures to pesticides and pyridostigmine bromide are causally associated with Gulf War illness. Evidence also continues to demonstrate that Gulf War illness is not the result of psychological stressors during the war." It also found additional evidence since the 2008 report for the role of
sarin in GWI, but inadequate evidence regarding exposures to oil well fires, vaccines, and depleted uranium to make new conclusions about them. During Operation Desert Storm, 41% of U.S. combat soldiers and 75% of UK combat soldiers were vaccinated against anthrax. While the
Food and Drug Administration (FDA) approved the vaccine, it never went through large-scale clinical trials. While recent studies have demonstrated the vaccine is highly
reactogenic, there is no clear evidence or epidemiological studies on Gulf War veterans linking the vaccine to Gulf War illness. Combining this with the lack of symptoms from current deployments of individuals who have received the vaccine led the Committee on Gulf War Veterans' Illnesses to conclude that the vaccine is not a likely cause of Gulf War illness for most ill veterans. Their work of the researchers was profiled by Gary Matsumoto in "Vaccine A". This research and theory was later criticized, and further research has leaned heavily against squalene in vaccinations causing GWS; Perhaps the most important points against this theory include that squalene antibodies have been detected in populations not exposed to squalene containing vaccinations, and that the anthrax vaccines used in the Gulf War did not actually contain squalene in any form.
Combat stress Research studies conducted since the war have consistently indicated that psychiatric illness, combat experience or other deployment-related stressors do not explain Gulf War veterans illnesses in the large majority of ill veterans, according to a
U.S. Department of Veterans Affairs (VA) review committee. An April 2010 Institute of Medicine review found, "the excess of unexplained medical symptoms reported by deployed [1991] Gulf war veterans cannot be reliably ascribed to any known psychiatric disorder", although they also concluded that "the constellation of unexplained symptoms associated with the Gulf War illness complex could result from interplay between both biological and psychological factors." == Pathobiology ==