Incidence of Mild Cognitive Impairment in Gulf War Veterans
Abstract
An estimated 250,000 Gulf War (GW) Veterans are afflicted by Gulf War Illness (GWI), a chronic health condition associated with several concomitant symptoms such as persistent fatigue, musculoskeletal pain, and cognitive complaints. Longitudinal studies suggest that most Veterans with GWI have not improved with time; instead, many have been getting worse. There have also been reports of a higher than expected incidence of cognitive impairment among GW Veterans. On the continuum of cognitive decline, mild cognitive impairment (MCI) is considered the transition between cognitive impairment associated with normal aging and the more serious decline associated with dementia. People with MCI have problems with memory, attention, language, and problem solving that are greater than expect for their age, but they are still able to perform activities of daily living (e.g., personal care, dressing, grooming, and feeding oneself). For this reason, people with MCI do not meet the criteria for dementia. Our preliminary data indicates that 12% of the deployed GW Veterans from the PI’s VA Merit study meet the actuarial criteria for MCI. This is likely double the prevalence of MCI in people under 60 in the general population. Moreover, the median age of GW Veterans with MCI was 48 years at the time of testing, more than 20 years younger than the typical age of MCI patients in the general population. Thus, our preliminary findings are consistent with the idea that GW Veterans are aging at a faster rate than the general population. Furthermore, GW Veterans with MCI have smaller hippocampal volume and thinner parietal cortex, two indications of neurodegenerative pathogenesis, compared to Veterans without MCI. In the general population, individuals with MCI are 3 to 5 times more likely to progress to any form of dementia compared to those with normal cognition. The proposed study will investigate whether the higher rate of MCI among deployed GW Veterans is a harbinger future higher rates of dementia in this Veteran population. This meets the FY20 GWIRP Overarching Challenge of consequences. The objectives of proposed study are twofold. First, we will cross-validate our preliminary findings of a higher than expected rate of MCI in deployed GW Veterans from the large, well-characterized Boston Gulf War Illness Consortium (GWIC) cohort. We will also compare hippocampal volume and parietal cortex thickness in GW Veterans with and without MCI in the GWIC cohort. Second, we will expand on our preliminary findings by investigating the underlying cause of MCI in deployed GW Veterans in the San Francisco VA (SF VA) and GWIC cohorts. Alzheimer’s disease (AD) is most common cause of MCI and dementia; amyloid ß (Aß) and tau are two molecular biomarkers of AD neuropathology. Vascular dementia is the second most common cause of MCI and dementia. Cerebrovascular disease, characterized by white matter hyperintensities (WMH) on magnetic resonance images (MRIs), is a primary cause of clinical deficits in vascular MCI and vascular dementia. The proposed study will investigate whether GW Veterans with MCI have AD or non-AD pathology by (1) examining levels of Aß and tau to determine whether GW Veterans with MCI fit the National Institute on Aging and Alzheimer’s Association research framework characterization of AD and (2) quantifying WMH volumes from the MRI scans to determine the cerebrovascular disease burden in the brains of GW Veterans with and without MCI. There is presently no cure for dementia; however, considerable progress has been made towards identifying intervention and preventive measures that may delay the onset of dementia. It is widely agreed upon that earlier intervention is a key to more effective treatment of AD and other related dementias. Because most GW Veterans with MCI are younger than the typical MCI patient in the general population and because most GW Veterans with MCI still have relatively preserved activities of daily functio
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 05, 2021
- Source ID
- W81XWH2110656
Entities
People
- Linda L Chao
Organizations
- Northern California Institute for Research and Education
- United States Army