Do Gulf War veterans with high levels of deployment-related exposures display symptoms suggestive of Parkinson’s disease?

Abstract

Objectives: Veterans of the 1991 Gulf War (GW) were exposed to a myriad of potentially hazardous chemicals during deployment. Epidemiological data suggest a possible link between chemical exposures and Parkinson’s disease (PD); however, there have been no reliable data on the incidence or prevalence of PD among GW veterans to date. This study included the following 2 questions: 1. Do deployed GW veterans display PD-like symptoms? and 2. Is there a relationship between the occurrence and quantity of PD-like symptoms, and the levels of deployment-related exposures in GW veterans?

Material and methods: Self-reports of symptoms and exposures to deployment-related chemicals were filled out by 293 GW veterans, 202 of whom had undergone 3 Tesla volumetric measurements of basal ganglia volumes. Correlation analyses were used to examine the relationship between the frequency of the veterans’ self-reported exposures to deployment-related chemicals, motor and non-motor symptoms of PD, and the total basal ganglia volumes.

Results: Healthy deployed GW veterans self-reported few PD-like non-motor symptoms and no motor symptoms. In contrast, GW veterans with Gulf War illness (GWI) self-reported more PD-like motor and non-motor symptoms, and more GW-related exposures. Compared to healthy deployed veterans, those with GWI also had lower total basal ganglia volumes.

Conclusions: 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 PD/prodromal PD, compared to healthy deployed GW veterans. Int J Occup Med Environ Health. 2019;32(4):503–26

Keywords: occupational exposure; pesticides; chemical exposure; Parkinson’s disease; basal ganglia; Gulf War.

Figure 1.

Parkinson’s disease-like non-motor symptoms (NMS) as a function of the a) 2 Gulf War-exposure indices in the entire study sample, b) healthy deployed veterans, c) Centers for Disease Control and Prevention Chronic Multisymptom Illness (CDC CMI) cases, and d) Kansas Gulf War illness (KGWI) cases in the study of Gulf War veterans (N = 293) recruited in 2002–2017 The Nisenbaum exposure index, based on Nisenbaum et al. [30], was derived by summing the self-reported frequency taking of PB pills, using cream or liquid and/or powdered pesticides on skin, and the presence or absence of experiences that lead the veteran to believe s/he was exposed to chemical agents while in the Gulf region. The Steele exposure index, based on Steele et al. [5], was derived by summing the self-reported frequency of taking PB and being within 1 mile of an exploding SCUD missile among veterans who served in Iraq and/or Kuwait and among veterans who did not serve in Iraq or Kuwait, it was derived by summing the self-reported frequency of wearing pesticide-treated uniforms, using cream or liquid and/or powdered pesticides on skin.

Figure 2.

Healthy veterans, and Kansas Gulf War illness (KGWI) and chronic multisymptom illness (CMI) cases, both without and with PD-like motor symptoms, in the study of Gulf War veterans (N = 293) recruited in 2002–2017