Exposure to Chemical Smoke, Chemical and Biological Agents
Although assessed in different ways, pesticide use is one of only two exposures consistently identified by Gulf War epidemiologic studies to be significantly linked with Gulf War illness. 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 Persian Gulf War has also been linked with neuro-cognitive deficits and neuro-endocrine alterations in Gulf War veterans. Thus, all available sources of evidence combine to support a consistent and compelling case that pesticide use during the Gulf War is causally linked to Gulf War illness.
Pyridostigmine Bromide (PB)
Along with pesticide use, Pyridostigmine Bromide is one of only two
exposures consistently identified by Gulf War epidemiologic studies to
be significantly linked with Gulf War illness. Several studies have identified
dose-response effects, indicating that veterans who took PB pills for
longer periods of time have higher illness rates than veterans who took
less PB. In addition, clinical studies have identified significant links
between PB use during the Gulf War and neuro-cognitive and neuro-endocrine
alterations after the war. These diverse types and sources of evidence
provide a consistent and persuasive case that use of PB during the Persian
Gulf War is causally linked with Gulf War illness.
Oil Well Fires
Widespread exposure to smoke from Kuwaiti oil well fires was unique to military service in the 1990-91 Persian Gulf War and most prominently affected forward location ground troops. Epidemiologic findings that relate oil well fire smoke exposure to Gulf War illness have been mixed, however a dose-response effect has been identified by several studies.
Although studies of Gulf War veterans do not provide consistent evidence that exposure to oil well fire smoke is a risk factor for Gulf War illness among most veterans, questions remain about the effects for personnel located in close proximity to burning oil wells for an extended period. Limited findings from epidemiologic studies indicate that higher level exposures to smoke from the Kuwaiti oil well fires may be associated with increased rates of asthma in Gulf War veterans and that a causal link with Gulf War illness cannot be ruled out.
Although there have been no reports that U.S. military forces encountered large-scale, high-dose exposures to chemical weapons during the Gulf War, concerns have emerged related to possible long-term effects of low-dose nerve agent exposures.
For example, DoD estimates that about 100,000 U.S. troops may have been exposed to low levels of nerve agents following weapons demolitions in March 1991 at Khamisiyah, Iraq, but questions have been raised about the models used to determine who was exposed and at what levels.
Studies of Persian Gulf War veterans have identified increased rates
of brain cancer and measurable differences in brain structure and function
that relate in a dose-response manner to modeled nerve agent exposure
levels resulting from the Khamisiyah demolitions. Findings from Gulf
War clinical studies suggest a link between Gulf War illness and low-level
nerve agent exposure cannot be ruled out.
A substantial number of Persian Gulf War military personnel contracted acute gastrointestinal and respiratory infections during their deployment, but there is little information concerning patterns of infection in theater and no evidence of widespread chronic illness resulting from those infections. Several studies have identified DNA indicators of mycoplasma (i.e., fungus) infection, but questions about testing methods have not been adequately addressed. Presently there is little clear evidence implicating infectious diseases as prominent causes of Gulf War illness.
Combinations of Exposures
Research on effects of combinations of Persian Gulf War-related exposures is limited. Studies consistently indicate that exposures in theater were highly correlated – that is, that military personnel most often experienced individual exposures in connection with multiple other exposures. This includes correlations between use of PB and pesticides and among different types of pesticides. However, there is little information from the many epidemiologic studies of Persian Gulf War veterans concerning the combined effects of Gulf War exposures.
Exposure to Depleted Uranium
uses of depleted uranium (DU) include defensive armor plating and armor-piercing
projectiles. DU munitions are controversial because of unanswered questions
about potential long-term health effects.
When DU munitions penetrate armor or burn, they create depleted uranium oxides in the form of dust that can be inhaled or contaminate wounds. Additionally, fragments of munitions or armor can become embedded in the body.
Health effects of DU are determined by factors such as the extent of exposure and whether it was internal or external.
Increased rates of immune-system disorders and other wide-ranging symptoms, including chronic pain, fatigue, and memory loss, have been reported in over one quarter of combat veterans of the 1991 Persian Gulf War, who were found to have up to 14 times the usual level of chromosome abnormalities in their genes.
DU is less toxic than other heavy metals, such as arsenic and mercury, and is only very weakly radioactive because of its long half-life. While any radiation exposure has risks, no conclusive epidemiological data have correlated DU exposure to specific human health effects, such as cancer. However, studies using cultured cells and laboratory rodents continue to suggest leukemogenic, genetic, reproductive, and neurological effects from chronic exposure.
A 2005 epidemiology review concluded: "In aggregate the human epidemiological evidence is consistent with increased risk of birth defects in offspring of persons exposed to DU.”
A 2001 study of 15,000 February 1991 U.S. Gulf War combat veterans and 15,000 control veterans found the Gulf War veterans were 1.8 (fathers) to 2.8 (mothers) times more likely to have children with birth defects, and after examination of their children's medical records two years later, the birth defect rate increased by more than 20 percent.
Veterans who may be at a higher risk include those who have internally retained fragments of DU from shrapnel wounds. A laboratory study on rats produced by the Armed Forces Radiobiology Research Institute showed that, after a study period of 6 months, rats treated with depleted uranium coming from implanted pellets, comparable to the average levels in the urine of Desert Storm veterans with retained DU fragments, had developed a significant tendency to lose weight with respect to the control group. In addition, substantial amounts of uranium were accumulating in their brains and central nervous systems and showed a significant reduction of neuronal activity in the hippocampus in response to external stimuli.
The conclusions of the study show that brain damage from chronic uranium intoxication is possible at lower doses than previously thought. Results from computer-based neuro-cognitive tests performed in 1997 showed an association between uranium in the urine and "problematic performance on automated tests assessing performance efficiency and accuracy."
Despite the information presented above, however, a number of other scientific studies have concluded that DU ammunition has no measurable detrimental health effects.