Plasma Biomarkers of Alzheimer's Disease Are Associated with Physical Functioning Outcomes Among Cognitively Normal Adults in the Multiethnic HABS-HD Cohort.

In this study, we examined the link between plasma Alzheimer's disease (AD) biomarkers and physical functioning outcomes within a community-dwelling, multiethnic cohort. Data from 1 328 cognitively unimpaired participants (n = 659 Mexican American and n = 669 non-Hispanic White) from the ongoing Health & Aging Brain Study-Health Disparities (HABS-HD) cohort were examined. Plasma AD biomarkers (amyloid beta [Aß]40, Aß42, total tau [t-tau], and neurofilament light chain [NfL]) were assayed using the ultra-sensitive Simoa platform. Physical functioning measures were the Timed Up and Go (TUG) and the Short Physical Performance Battery (SPPB). Cross-sectional linear regression analyses revealed that plasma Aß 40 (p < .001), Aß 42 (p = .003), and NfL (p < .001) were each significantly associated with TUG time in seconds. Plasma Aß 40 (p < .001), Aß 42 (p < .001), t-tau (p = .002), and NfL (p < .001) were each significantly associated with SPPB Total Score. Additional analyses demonstrate that the link between plasma AD biomarkers and physical functioning outcomes were strongest among Mexican Americans. Plasma AD biomarkers are receiving a great deal of attention in the literature and are now available clinically including use in clinical trials. The examination of AD biomarkers and physical functioning may allow for the development of risk profiles, which could stratify a person's risk for neurodegenerative diseases, such as AD, based on plasma AD biomarkers, physical functioning, ethnicity, or a combination of these measures prior to the onset of cognitive impairment.

The Health & Aging Brain among Latino Elders (HABLE) study methods and participant characteristics.

INTRODUCTION: Mexican Americans remain severely underrepresented in Alzheimer's disease (AD) research. The Health & Aging Brain among Latino Elders (HABLE) study was created to fill important gaps in the existing literature. METHODS: Community-dwelling Mexican Americans and non-Hispanic White adults and elders (age 50 and above) were recruited. All participants underwent comprehensive assessments including an interview, functional exam, clinical labs, informant interview, neuropsychological testing, and 3T magnetic resonance imaging (MRI) of the brain. Amyloid and tau positron emission tomography (PET) scans were added at visit 2. Blood samples were stored in the Biorepository. RESULTS: Data was examined from n = 1705 participants. Significant group differences were found in medical, demographic, and sociocultural factors. Cerebral amyloid and neurodegeneration imaging markers were significantly different between Mexican Americans and non-Hispanic Whites. DISCUSSION: The current data provide strong support for continued investigations that examine the risk factors for and biomarkers of AD among diverse populations.

Polypharmacy and Cognition Function Among Rural Adults.

BACKGROUND: Polypharmacy (using≥5 medications) is associated with poor health outcomes. Mixed results from past studies surrounding chronic medication use, control of chronic conditions, and their effects on cognitive performance warrant further attention. OBJECTIVE: Investigate a link between polypharmacy and cognition function in rural-dwelling adults in Texas, USA. METHODS: Project FRONTIER (Facing Rural Obstacles to Healthcare Now Through Intervention, Education & Research) is a cross-sectional epidemiological study using community-based participatory research in three counties of Texas. Residents age > 40 were eligible for inclusion. The primary outcome is cognitive impairment, and exposures of interest are polypharmacy; comorbidities; and diabetes, hypertension, and depression medication. Logistic regression was used to assess association. RESULTS: Six hundred eighty-nine individuals participated; the mean age was 61, and the majority were female (68.7%).The median number of medications taken by participants was 3.3 (IQR: 0-5); the rate of polypharmacy was 29.6%. Anti-hypertensive agents were the most common medications (15%) used. Polypharmacy users were 2.84 times more likely to have cognitive impairment [OR: 2.84, 95%CI (1.32-6.09)] than those using < 5 medications. Participants on hypertensive medications had 1.85 times higher odds [OR: 1.85, 95%CI (1.14-3.01)] of having cognitive impairment than those who did not have cognitive impairment. CONCLUSION: Polypharmacy increases the odds of cognitive impairment. The odds of presenting with cognitive impairment increased as the number of medications increased. Additionally, we identified a large, concerning number of participants with pharmacotherapy and poor chronic disease management. A larger study should examine medication adherence among rural elders to manage chronic disease and any healthcare barriers to adherence.

The impact of comorbid depression-diabetes on proteomic outcomes among community-dwelling Mexican Americans with mild cognitive impairment.

BACKGROUND: Mexican Americans suffer from a disproportionate burden of modifiable risk factors, which may contribute to the health disparities in mild cognitive impairment (MCI) and Alzheimer's disease (AD). OBJECTIVE: The purpose of this study was to elucidate the impact of comorbid depression and diabetes on proteomic outcomes among community-dwelling Mexican American adults and elders. METHODS: Data from participants enrolled in the Health and Aging Brain among Latino Elders study was utilized. Participants were 50 or older and identified as Mexican American (N = 514). Cognition was assessed via neuropsychological test battery and diagnoses of MCI and AD adjudicated by consensus review. The sample was stratified into four groups: Depression only, Neither depression nor diabetes, Diabetes only, and Comorbid depression and diabetes. Proteomic profiles were created via support vector machine analyses. RESULTS: In Mexican Americans, the proteomic profile of MCI may change based upon the presence of diabetes. The profile has a strong inflammatory component and diabetes increases metabolic markers in the profile. CONCLUSION: Medical comorbidities may impact the proteomics of MCI and AD, which lend support for a precision medicine approach to treating this disease.

Vascular Depression and Cognition in Mexican Americans.

BACKGROUND: Mexican Americans are at increased risk of developing mild cognitive impairment (MCI) and Alzheimer's disease compared to non-Hispanic whites. This study sought to examine the relationship between vascular risk, depression, and cognition in Mexican American elders. METHODS: Data from 470 (390 normal controls, 80 MCI patients) Mexican Americans enrolled in the Health and Aging Brain among Latino Elders (HABLE) study were used. The cardiovascular risk was assessed by the Framingham Risk Score. Cognition was assessed with a neuropsychological battery, and depression was assessed based on scores from the Geriatric Depression Scale (GDS). ANOVAs were utilized to determine the differences in neuropsychological scores of normal controls with and without depression and CVD risk (low vs. high). Follow-up logistic regression was conducted to determine MCI risk. RESULTS: The results of this study indicated that comorbid depression and a high CVD risk were associated with poorer cognitive performance in Mexican Americans. Depressed women with high CVD risk were more likely to have executive dysfunction, language deficits, and poorer global cognition than nondepressed women with a high CVD risk. In Mexican American men, those with a high vascular risk and depression were more likely to have executive dysfunction and poorer immediate memory than the nondepressed high-risk group. Higher GDS scores (OR = 1.10; 95% CI 1.02-1.10, p = 0.001) and higher vascular risk scores (OR = 1.05; 95% CI 1.02-1.10, p = 0.001) significantly predicted MCI status in Mexican Americans. CONCLUSION: The results of this study indicated that comorbid depression and a high CVD risk were associated with poorer cognitive performance and increased risk of MCI in Mexican Americans.

The Link between Potassium and Mild Cognitive Impairment in Mexican-Americans.

BACKGROUND: Recent evidence suggests that increasing dietary intake of minerals reduces the risk of dementia. This study aimed to examine the relationship between potassium and diagnosis of mild cognitive impairment (MCI) in a sample of older Mexican-Americans from rural and urban populations. METHODS: The sample was formed of a total of 139 participants with MCI and 371 normal controls from two independent cohorts: a rural cohort (Facing Rural Obstacles to Healthcare Now through Intervention, Education and Research [Project FRONTIER]) and an urban cohort (the Health and Aging Brain among Latino Elders [HABLE] study). Serum electrolytes examined were sodium and potassium. Age and education were entered in the model as covariates. RESULTS: Across both cohorts, the Project FRONTIER (OR = 3.1; p = 0.01) and the HABLE Project (OR = 2.0; p = 0.04), the results indicated that serum potassium levels significantly increased the risk of diagnosis of MCI. CONCLUSION: Our finding suggested a link between serum potassium levels and a diagnosis of MCI in Mexican-Americans. The results of this study support a previous research which has suggested that the risk factors for MCI may vary by ethnicity.