The prevalence of mild cognitive impairment in Gulf War veterans: a follow-up study

Linda L Chao; Kimberly Sullivan; Maxine H Krengel; Ronald J Killiany; Lea Steele; Nancy G Klimas; Bang-Bong Koo

doi:10.3389/fnins.2023.1301066

The prevalence of mild cognitive impairment in Gulf War veterans: a follow-up study

Front Neurosci. 2024 Jan 22:17:1301066. doi: 10.3389/fnins.2023.1301066. eCollection 2023.

Authors

Linda L Chao^{1

2

3}, Kimberly Sullivan⁴, Maxine H Krengel⁵, Ronald J Killiany⁶, Lea Steele⁷, Nancy G Klimas^{8

9}, Bang-Bong Koo⁶

Affiliations

¹ Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States.
² Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, United States.
³ San Francisco Veterans Affairs Health Care System, San Francisco, CA, United States.
⁴ Department of Environmental Health, Boston University School of Public Health, Boston, MA, United States.
⁵ Department of Neurology, Boston University School of Medicine, Boston, MA, United States.
⁶ Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States.
⁷ Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, United States.
⁸ Dr. Kiran C. Patel College of Osteopathic Medicine, Institute for Neuro-Immune Medicine, Nova Southeastern University, Fort Lauderdale, FL, United States.
⁹ Geriatric Research Education and Clinical Center (GRECC), Miami VA Medical Center, Miami, FL, United States.

Abstract

Introduction: Gulf War Illness (GWI), also called Chronic Multisymptom Illness (CMI), is a multi-faceted condition that plagues an estimated 250,000 Gulf War (GW) veterans. Symptoms of GWI/CMI include fatigue, pain, and cognitive dysfunction. We previously reported that 12% of a convenience sample of middle aged (median age 52 years) GW veterans met criteria for mild cognitive impairment (MCI), a clinical syndrome most prevalent in older adults (e.g., ≥70 years). The current study sought to replicate and extend this finding.

Methods: We used the actuarial neuropsychological criteria and the Montreal Cognitive Assessment (MoCA) to assess the cognitive status of 952 GW veterans. We also examined regional brain volumes in a subset of GW veterans (n = 368) who had three Tesla magnetic resonance images (MRIs).

Results: We replicated our previous finding of a greater than 10% rate of MCI in four additional cohorts of GW veterans. In the combined sample of 952 GW veterans (median age 51 years at time of cognitive testing), 17% met criteria for MCI. Veterans classified as MCI were more likely to have CMI, history of depression, and prolonged (≥31 days) deployment-related exposures to smoke from oil well fires and chemical nerve agents compared to veterans with unimpaired and intermediate cognitive status. We also replicated our previous finding of hippocampal atrophy in veterans with MCI, and found significant group differences in lateral ventricle volumes.

Discussion: Because MCI increases the risk for late-life dementia and impacts quality of life, it may be prudent to counsel GW veterans with cognitive dysfunction, CMI, history of depression, and high levels of exposures to deployment-related toxicants to adopt lifestyle habits that have been associated with lowering dementia risk. With the Food and Drug Administration's recent approval of and the VA's decision to cover the cost for anti-amyloid β (Aβ) therapies, a logical next step for this research is to determine if GW veterans with MCI have elevated Aβ in their brains.

Keywords: Gulf War; cognition; hippocampus; mild cognitive impairment; neuroimaging; neuropsychology.

Abstract

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