Olfactory and cognitive decrements in 1991 Gulf War veterans with gulf war illness/chronic multisymptom illness

Abstract Background Gulf War illness (GWI)/Chronic Multisymptom Illness (CMI) is a disorder related to military service in the 1991 Gulf War (GW). Prominent symptoms of GWI/CMI include fatigue, pain, and cognitive dysfunction. Although anosmia is not a typical GWI/CMI symptom, anecdotally some GW ve...

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Main Author: Linda L. Chao
Format: Article
Language:English
Published: BMC 2024-01-01
Series:Environmental Health
Subjects:
Online Access:https://doi.org/10.1186/s12940-024-01058-2
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author Linda L. Chao
author_facet Linda L. Chao
author_sort Linda L. Chao
collection DOAJ
description Abstract Background Gulf War illness (GWI)/Chronic Multisymptom Illness (CMI) is a disorder related to military service in the 1991 Gulf War (GW). Prominent symptoms of GWI/CMI include fatigue, pain, and cognitive dysfunction. Although anosmia is not a typical GWI/CMI symptom, anecdotally some GW veterans have reported losing their sense smell shortly after the war. Because olfactory deficit is a prodromal symptom of neurodegenerative diseases like Parkinson’s and Alzheimer’s disease, and because we previously reported suggestive evidence that deployed GW veterans may be at increased risk for Mild Cognitive Impairment (MCI) and dementia, the current study examined the relationship between olfactory and cognitive function in deployed GW veterans. Methods Eighty deployed GW veterans (mean age: 59.9  ±7.0; 4 female) were tested remotely with the University of Pennsylvania Smell Identification Test (UPSIT) and the Montreal Cognitive Assessment (MoCA). Veterans also completed self-report questionnaires about their health and deployment-related exposures and experiences. UPSIT and MoCA data from healthy control (HC) participants from the Parkinson’s Progression Markers Initiative (PPMI) study were downloaded for comparison. Results GW veterans had a mean UPSIT score of 27.8  ± 6.3 (range 9–37) and a mean MoCA score of 25.3  ± 2.8 (range 19–30). According to age- and sex-specific normative data, 31% of GW veterans (vs. 8% PPMI HCs) had UPSIT scores below the 10th percentile. Nearly half (45%) of GW veterans (vs. 8% PPMI HCs) had MoCA scores below the cut-off for identifying MCI. Among GW veterans, but not PPMI HCs, there was a positive correlation between UPSIT and MoCA scores (Spearman’s ρ = 0.39, p < 0.001). There were no significant differences in UPSIT or MoCA scores between GW veterans with and without history of COVID or between those with and without Kansas GWI exclusionary conditions. Conclusions We found evidence of olfactory and cognitive deficits and a significant correlation between UPSIT and MoCA scores in a cohort of 80 deployed GW veterans, 99% of whom had CMI. Because impaired olfactory function has been associated with increased risk for MCI and dementia, it may be prudent to screen aging, deployed GW veterans with smell identification tests so that hypo- and anosmic veterans can be followed longitudinally and offered targeted neuroprotective therapies as they become available.
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spelling doaj.art-2784651617d94d29aaae1286e2bfe97f2024-03-05T20:09:36ZengBMCEnvironmental Health1476-069X2024-01-0123111010.1186/s12940-024-01058-2Olfactory and cognitive decrements in 1991 Gulf War veterans with gulf war illness/chronic multisymptom illnessLinda L. Chao0Departments of Radiology & Biomedical Imaging and Psychiatry & Behavioral Science, University of CalfiorniaAbstract Background Gulf War illness (GWI)/Chronic Multisymptom Illness (CMI) is a disorder related to military service in the 1991 Gulf War (GW). Prominent symptoms of GWI/CMI include fatigue, pain, and cognitive dysfunction. Although anosmia is not a typical GWI/CMI symptom, anecdotally some GW veterans have reported losing their sense smell shortly after the war. Because olfactory deficit is a prodromal symptom of neurodegenerative diseases like Parkinson’s and Alzheimer’s disease, and because we previously reported suggestive evidence that deployed GW veterans may be at increased risk for Mild Cognitive Impairment (MCI) and dementia, the current study examined the relationship between olfactory and cognitive function in deployed GW veterans. Methods Eighty deployed GW veterans (mean age: 59.9  ±7.0; 4 female) were tested remotely with the University of Pennsylvania Smell Identification Test (UPSIT) and the Montreal Cognitive Assessment (MoCA). Veterans also completed self-report questionnaires about their health and deployment-related exposures and experiences. UPSIT and MoCA data from healthy control (HC) participants from the Parkinson’s Progression Markers Initiative (PPMI) study were downloaded for comparison. Results GW veterans had a mean UPSIT score of 27.8  ± 6.3 (range 9–37) and a mean MoCA score of 25.3  ± 2.8 (range 19–30). According to age- and sex-specific normative data, 31% of GW veterans (vs. 8% PPMI HCs) had UPSIT scores below the 10th percentile. Nearly half (45%) of GW veterans (vs. 8% PPMI HCs) had MoCA scores below the cut-off for identifying MCI. Among GW veterans, but not PPMI HCs, there was a positive correlation between UPSIT and MoCA scores (Spearman’s ρ = 0.39, p < 0.001). There were no significant differences in UPSIT or MoCA scores between GW veterans with and without history of COVID or between those with and without Kansas GWI exclusionary conditions. Conclusions We found evidence of olfactory and cognitive deficits and a significant correlation between UPSIT and MoCA scores in a cohort of 80 deployed GW veterans, 99% of whom had CMI. Because impaired olfactory function has been associated with increased risk for MCI and dementia, it may be prudent to screen aging, deployed GW veterans with smell identification tests so that hypo- and anosmic veterans can be followed longitudinally and offered targeted neuroprotective therapies as they become available.https://doi.org/10.1186/s12940-024-01058-2Gulf warVeteransCognitionCognitiveOlfaction, neurotoxicant
spellingShingle Linda L. Chao
Olfactory and cognitive decrements in 1991 Gulf War veterans with gulf war illness/chronic multisymptom illness
Environmental Health
Gulf war
Veterans
Cognition
Cognitive
Olfaction, neurotoxicant
title Olfactory and cognitive decrements in 1991 Gulf War veterans with gulf war illness/chronic multisymptom illness
title_full Olfactory and cognitive decrements in 1991 Gulf War veterans with gulf war illness/chronic multisymptom illness
title_fullStr Olfactory and cognitive decrements in 1991 Gulf War veterans with gulf war illness/chronic multisymptom illness
title_full_unstemmed Olfactory and cognitive decrements in 1991 Gulf War veterans with gulf war illness/chronic multisymptom illness
title_short Olfactory and cognitive decrements in 1991 Gulf War veterans with gulf war illness/chronic multisymptom illness
title_sort olfactory and cognitive decrements in 1991 gulf war veterans with gulf war illness chronic multisymptom illness
topic Gulf war
Veterans
Cognition
Cognitive
Olfaction, neurotoxicant
url https://doi.org/10.1186/s12940-024-01058-2
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