Veterans of the Gulf War are not, as a whole, more likely to experience Parkinson’s disease-like symptoms, a new study has found. However, veterans with Gulf War illness do appear to be at greater risk of these symptoms.
The study, “Do Gulf War veterans with high levels of deployment-related exposures display symptoms suggestive of Parkinson’s disease?,” was published in the International Journal of Occupational Medicine and Environmental Health.
The Gulf War, which also is known as the Persian Gulf War or the First Gulf War, took place in 1991. Many people were exposed to toxic chemicals, including pesticides, smoke from oil well fires, and low levels of chemical warfare agents. This is suspected to be one of the causes of Gulf War illness (GWI), which affects as many as a third of Gulf War veterans and is characterized by persistent fatigue, pain, and problems with memory, concentration, and mood.
Interestingly, GWI and Parkinson’s disease share many features. Both have been linked to chemical exposures. Both are variable in how symptoms manifest. And, GWI symptoms resemble some non-motor symptoms of Parkinson’s (e.g., fatigue and mood problems). Yet, Parkinson’s has never been explicitly studied in veterans of the Gulf War.
In this study, 293 Gulf War veterans were recruited and given questionnaires that included questions about Parkinson’s-like symptoms, GWI symptoms, and exposure to chemicals during the war. The study participants were predominantly white (72%) and male (84%), and most individuals had served in the army (57%).
A total of 122 (42%) people in the group had GWI disease as assessed by the Kansas Gulf War Military History and Health Questionnaire. Additionally, 231 (79%) veterans met the United States Centers for Disease Control and Prevention (CDC) criteria for “chronic multisymptom illness” (CMI), which is basically GWI but with less-stringent diagnostic criteria. Veterans who had neither were deemed “healthy” for the sake of the researchers’ analysis.
Veterans with GWI or CMI were less likely to have served as officers in the war, they were more likely to be ethnic minorities and to be younger and less-educated than their healthy peers.
Among the healthy veterans, there were no Parkinson’s-like motor symptoms, and few non-motor symptoms reported, which suggests that Gulf War deployment alone doesn’t increase the likelihood of developing these symptoms.
However, participants with GWI or CMI were significantly more likely to report Parkinson’s-like symptoms (both motor and non-motor) than their healthy peers.
Veterans with GWI or CMI also were more likely to have been exposed to more chemicals during the war, and more chemical exposure was associated with a greater likelihood of having non-motor Parkinson’s symptoms across the whole group. (Although this association wasn’t statistically significant among subgroups, for example, in people with GWI.)
Additionally, among all participants, those with Parkinson’s-like motor symptoms were more likely to report having seen their area “being sprayed or fogged with pesticides” compared to veterans without such motor symptoms.
The researchers also measured the size of 202 participants’ basal ganglia, a region of the brain that is implicated in Parkinson’s disease. Interestingly, having a smaller basal ganglia was statistically linked to a greater likelihood of having GWI or CMI, but it wasn’t linked to Parkinson’s-like symptoms or to wartime chemical exposures.
Some of the “muddiness” of this data likely comes from the inherent inaccuracy of relying on self-reporting and the difficulty of getting precise measurements about something like chemical exposure during a war. Additionally, it’s important to note that this study’s 293 participants are unlikely to be truly representative of the 700,000 or so United States Gulf War veterans.
“Although little is known about the long-term consequences of GWI, findings from this study suggest that veterans with GWI show more symptoms as those seen in [Parkinson’s]/prodromal [Parkinson’s], compared to healthy deployed GW veterans,” the researchers wrote.
However, they caution that “[b]ecause the present study did not clinically evaluate the veterans involved for [Parkinson’s], future studies will be necessary to determine if [GWI] and/or CMI cases truly are at increased risk of developing [Parkinson’s disease].”