The time course of motor and cognitive decline in older adults and their associations with brain pathologies: a multicohort study

BACKGROUND

Many studies have reported that impaired gait precedes cognitive impairment in older people. We aimed to characterise the time course of cognitive and motor decline in older individuals and the association of these declines with the pathologies of Alzheimer's disease and related dementias.

METHODS

This multicohort study used data from three community-based cohort studies (Religious Orders Study, Rush Memory and Aging Project, and Minority Aging Research Study, all in the USA). The inclusion criteria for all three cohorts were no clinical dementia at the time of enrolment and consent to annual clinical assessments. Eligible participants consented to post-mortem brain donation and had post-mortem pathological assessments and three or more repeated annual measures of cognition and motor functions. Clinical and post-mortem data were analysed using functional mixed-effects models. Global cognition was based on 19 neuropsychological tests, a hand strength score was based on grip and pinch strength, and a gait score was based on the number of steps and time to walk 8 feet and turn 360°. Brain pathologies of Alzheimer's disease and related dementias were assessed at autopsy.

FINDINGS

From 1994 to 2022, there were 1570 eligible cohort participants aged 65 years or older, 1303 of whom had cognitive and motor measurements and were included in the analysis. Mean age at death was 90·3 years (SD 6·3), 905 (69%) participants were female, and 398 (31%) were male. Median follow-up time was 9 years (IQR 5-11). On average, cognition was stable from 25 to 15 years before death, when cognition began to decline. By contrast, gait function and hand strength declined during the entire study. The combinations of pathologies of Alzheimer's disease and related dementias associated with cognitive and motor decline and their onsets of associations varied; only tau tangles, Parkinson's disease pathology, and macroinfarcts were associated with decline of all three phenotypes. Tau tangles were significantly associated with cognitive decline, gait function decline, and hand function decline (p<0·0001 for each); however, the association with cognitive decline persisted for more than 11 years before death, but the association with hand strength only began 3·57 years before death and the association with gait began 3·49 years before death. By contrast, the association of macroinfarcts with declining gait function began 9·25 years before death (p<0·0001) compared with 6·65 years before death (p=0·0005) for cognitive decline and 2·66 years before death (p=0·024) for decline in hand strength.

INTERPRETATION

Our findings suggest that average motor decline in older adults precedes cognitive decline. Macroinfarcts but not tau tangles are associated with declining gait function that precedes cognitive decline. This suggests the need for further studies to test if gait impairment is a clinical proxy for preclinical vascular cognitive impairment.

FUNDING

National Institutes of Health.

Everyday Discrimination Is Associated With Higher Odds of Hospitalizations Among Older African Americans

BACKGROUND

Everyday discrimination-experiences of being treated unfairly based on background characteristics like race-is linked to poor physical and mental health throughout the lifespan. Whether more experiences of discrimination are associated with higher odds of being hospitalized in older African Americans has not been explored.

METHODS

Community-dwelling participants from 3 longitudinal cohort studies (N = 446, age 65+ years) with discrimination scores and ≥12 months of linked Medicare claims were included. Hospitalizations were identified using Medicare fee-for-service claims, available for an average of 6.2 (SD: 3.7) years of follow-up after baseline.

RESULTS

In mixed-effects ordinal logistic regression models (outcomes of 0, 1, or 2+ hospitalizations per year) adjusted for age, sex, education, and income, higher discrimination was associated with higher odds of total annual hospitalizations (odds ratio [OR] per point higher = 1.09, 95% confidence intervals [95% CI]: 1.02-1.17). Results were similar when accounting for depressive symptoms.

CONCLUSIONS

Higher exposure to everyday discrimination is associated with higher odds of hospitalization among older African Americans. Mechanisms underlying associations should be explored further to understand how hospitalizations may be reduced in older African Americans.

Large-scale Deep Proteomic Analysis in Alzheimer's Disease Brain Regions Across Race and Ethnicity

Introduction

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease, yet our comprehension predominantly relies on studies within the non-Hispanic White (NHW) population. Here we aimed to provide comprehensive insights into the proteomic landscape of AD across diverse racial and ethnic groups.

Methods

Dorsolateral prefrontal cortex (DLPFC) and superior temporal gyrus (STG) brain tissues were donated from multiple centers (Mayo Clinic, Emory University, Rush University, Mt. Sinai School of Medicine) and were harmonized through neuropathological evaluation, specifically adhering to the Braak staging and CERAD criteria. Among 1105 DLPFC tissue samples (998 unique individuals), 333 were from African American donors, 223 from Latino Americans, 529 from NHW donors, and the rest were from a mixed or unknown racial background. Among 280 STG tissue samples (244 unique individuals), 86 were African American, 76 Latino American, 116 NHW and the rest were mixed or unknown ethnicity. All tissues were uniformly homogenized and analyzed by tandem mass tag mass spectrometry (TMT-MS).

Results

As a Quality control (QC) measure, proteins with more than 50% missing values were removed and iterative principal component analysis was conducted to remove outliers within brain regions. After QC, 9,180 and 9,734 proteins remained in the DLPC and STG proteome, respectively, of which approximately 9,000 proteins were shared between regions. Protein levels of microtubule-associated protein tau (MAPT) and amyloid-precursor protein (APP) demonstrated AD-related elevations in DLPFC tissues with a strong association with CERAD and Braak across racial groups. APOE4 protein levels in brain were highly concordant with APOE genotype of the individuals.

Discussion

This comprehensive region resolved large-scale proteomic dataset provides a resource for the understanding of ethnoracial-specific protein differences in AD brain.

Bridging the Gap: Multi-Omics Profiling of Brain Tissue in Alzheimer's Disease and Older Controls in Multi-Ethnic Populations

INTRODUCTION

Multi-omics studies in Alzheimer's disease (AD) revealed many potential disease pathways and therapeutic targets. Despite their promise of precision medicine, these studies lacked African Americans (AA) and Latin Americans (LA), who are disproportionately affected by AD.

METHODS

To bridge this gap, Accelerating Medicines Partnership in AD (AMP-AD) expanded brain multi-omics profiling to multi-ethnic donors.

RESULTS

We generated multi-omics data and curated and harmonized phenotypic data from AA (n=306), LA (n=326), or AA and LA (n=4) brain donors plus Non-Hispanic White (n=252) and other (n=20) ethnic groups, to establish a foundational dataset enriched for AA and LA participants. This study describes the data available to the research community, including transcriptome from three brain regions, whole genome sequence, and proteome measures.

DISCUSSION

Inclusion of traditionally underrepresented groups in multi-omics studies is essential to discover the full spectrum of precision medicine targets that will be pertinent to all populations affected with AD.

School racial composition, effect modification by caring teacher/staff presence, and mid/late-life depressive symptoms: findings from the Study of Healthy Aging among African Americans

For Black students in the United States, attending schools with a higher proportion of White students is associated with worse mental and physical health outcomes in adolescence/early adulthood. No prior studies evaluate K-12 school racial composition and later-life mental health. In a cohort of Black adults ages 50+ in Northern California who retrospectively self-reported school racial composition for grades 1, 6, 9, and 12, we assessed the association between attending a school with mostly Black students vs. not and mid/late-life depressive symptoms (8-item PROMIS depression score, standardized to US adult population) using age-, sex/gender-, southern US birth-, and parental education-adjusted generalized estimating equations, and assessed effect modification by caring teacher/staff presence. Later-life depressive symptoms were lower among those who attended schools with mostly Black students in grades 1 and 6 (b=-0.12, 95% CI: -0.23, 0.00 and b=-0.11, 95% CI: -0.22, 0.00, respectively). In grade 6, this difference was larger for students without an adult at school who cared about them (b=-0.29, 95% CI: -0.51, -0.07 vs. b=-0.04, 95% CI: -0.17, 0.09). Among Black Americans, attending early school with mostly Black students may have later life mental health benefits; this protective association appears more important for students without caring teachers/staff.

Healthy Lifestyle and Cognition in Older Adults With Common Neuropathologies of Dementia

Importance

A healthy lifestyle is associated with better cognitive functioning in older adults, but whether this association is independent of the accumulation of dementia-related pathologies in the brain is uncertain.

Objective

To determine the role of postmortem brain pathology, including β-amyloid load, phosphorylated tau tangles, cerebrovascular pathology, and other brain pathologies, in the association between lifestyle and cognition proximate to death.

Design, Setting, and Participants

This cohort study used data from the Rush Memory and Aging Project, a longitudinal clinical-pathologic study with autopsy data from 1997 to 2022 and up to 24 years of follow-up. Participants included 754 deceased individuals with data on lifestyle factors, cognitive testing proximate to death, and a complete neuropathologic evaluation at the time of these analyses. Data were analyzed from January 2023 to June 2023.

Exposures

A healthy lifestyle score was developed based on self-reported factors, including noncurrent smoking, at least 150 minutes of physical activity per week, limiting alcohol consumption, a Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet score higher than 7.5, and a late-life cognitive activity score higher than 3.2. The lifestyle score ranges from 0 to 5, with higher scores reflecting a healthier lifestyle.

Main Outcomes and Measures

The global cognitive score was derived from a battery of nineteen standardized tests. Brain pathology measures included β-amyloid load, phosphorylated tau tangles, global Alzheimer disease pathology, vascular brain pathologies, Lewy body, hippocampal sclerosis, and TAR DNA-binding protein 43.

Results

Of 586 included decedents, 415 (70.8%) were female, 171 (29.2%) were male, and the mean (SD) age at death was 90.9 (6.0) years. Higher lifestyle score was associated with better global cognitive functioning proximate to death. In the multivariable-adjusted model, a 1-point increase in lifestyle score was associated with 0.216 (SE = 0.036, P < .001) units higher in global cognitive scores. Neither the strength nor the significance of the association changed substantially when common dementia-related brain pathologies were included in the multivariable-adjusted models. The β estimate after controlling for the β-amyloid load was 0.191 (SE = 0.035; P < .001). A higher lifestyle score was associated with lower β-amyloid load in the brain (β = -0.120; SE = 0.041; P = .003), and 11.6% of the lifestyle-cognition association was estimated through β-amyloid load.

Conclusions and Relevance

This study found that in older adults, a healthy lifestyle may provide a cognitive reserve to maintain cognitive abilities independently of common neuropathologies of dementia.

Childhood and Adulthood Trauma Associate With Cognitive Aging Among Black and White Older Adults

Sociocontextual factors powerfully shape risk for age-related cognitive impairment, including excess risk burdening medically underserved populations. Lifecourse adversity associates with cognitive aging, but harms are likely mitigable. Understanding population-salient relationships and sensitive periods for exposure is crucial for targeting clinical interventions.

OBJECTIVE

The authors examined childhood and adulthood traumatic events in relation to cognition among Black and White older adults in the Health and Retirement Study (HRS).

PARTICIPANTS

Participants (N = 13,952) aged 55+ had complete lifetime trauma and cognitive testing data at the 2006/08, 2010/12, and/or 2014/16 waves.

MEASURES

Trauma indices comprised childhood and adulthood event counts. Outcomes included baseline performance and trajectories on the Telephone Interview for Cognitive Status.

DESIGN

Main and nonlinear trauma effects were modeled via linear regression, and overall contributions assessed with omnibus likelihood ratio tests.

RESULTS

Black participants (N = 2,345) reported marginally lower adulthood trauma exposure than White participants (N = 11,607) with no other exposure differentials observed. In White participants only, greater childhood trauma exposure predicted worse baseline cognition but slower change over time. Across race, adulthood trauma robustly associated with baseline cognition. Relationships were frequently nonlinear: low but nonzero trauma predicted highest cognitive scores, with much poorer cognition observed as trauma exposure increased. Relationships between adulthood trauma and trajectory were limited to the White sample.

CONCLUSION

Traumatic experiences, particularly in adulthood, may impact late-life cognitive health if not addressed. Findings highlight foci for clinical researchers and providers: adverse life events as a source of cognitive risk, and identification of community-specific resources that buffer behavioral, physical, and mental health sequelae of previous and incident trauma.

Changes in Body Mass Index and Incident Mild Cognitive Impairment Among African American Older Adults

BACKGROUND

Previous research suggests a decline in body mass index (BMI) among older adults is associated with negative health outcomes, including mild cognitive impairment (MCI) and incident dementia. However, no studies have examined the effects of education or developing MCI on BMI trajectories over time. The purpose of this investigation was to characterize trajectories of change in BMI among older adults who develop MCI.

METHODS

Participants were from the Minority Aging Research Study (MARS), a longitudinal cohort study of cognitive decline and Alzheimer's disease in older African Americans living in the greater Chicago, Illinois, area. The study included annual clinical evaluations of cognitive status, as well as measurements of height and weight for BMI calculation. Older African American participants without cognitive impairment at baseline were included in the present analysis (N = 436, 78% women, mean baseline age = 72 [SD = 5.7], mean education = 15 [SD = 3.5]).

RESULTS

In piecewise linear mixed-effects models that included a random intercept and 2 random slopes, BMI declined over time (B = -0.20, SE = 0.02, p < .001), with a faster decline after MCI diagnosis (additional decline, B = -0.15, SE = 0.06, p = .019). Older age was associated with lower baseline BMI (B = -0.19, SE = 0.05, p < .001), as was higher education (B = -0.34, SE = 0.09, p < .001). Further, higher education was associated with a slower decline in BMI before MCI (B = 0.02, SE = 0.006, p = .001), but a faster decline after MCI (B = -0.06, SE = 0.022, p = .003).

CONCLUSIONS

These results suggest an accelerated decline in BMI following an MCI diagnosis, with higher education related to an even faster BMI decline.

Chronic traumatic encephalopathy and aging-related tau astrogliopathy in community-dwelling older persons with and without moderate-to-severe traumatic brain injury

This study examined the frequency of chronic traumatic encephalopathy-neuropathologic change (CTE-NC) and aging-related tau astrogliopathy (ARTAG) in community-dwelling older adults and tested the hypothesis that these tau pathologies are associated with a history of moderate-to-severe traumatic brain injury (msTBI), defined as a TBI with loss of consciousness >30 minutes. We evaluated CTE-NC, ARTAG, and Alzheimer disease pathologies in 94 participants with msTBI and 94 participants without TBI matched by age, sex, education, and dementia status TBI from the Rush community-based cohorts. Six (3%) of brains showed the pathognomonic lesion of CTE-NC; only 3 of these had a history of msTBI. In contrast, ARTAG was common in older brains (gray matter ARTAG = 77%; white matter ARTAG = 54%; subpial ARTAG = 51%); there were no differences in severity, type, or distribution of ARTAG pathology with respect to history of msTBI. Furthermore, those with msTBI did not have higher levels of PHF-tau tangles density but had higher levels of amyloid-β load (Estimate = 0.339, SE = 0.164, p = 0.040). These findings suggest that CTE-NC is infrequent while ARTAG is common in the community and that both pathologies are unrelated to msTBI. The association of msTBI with amyloid-β, rather than with tauopathies suggests differential mechanisms of neurodegeneration in msTBI.

Changes in an in-vivo classifier of ARTerioloSclerosis (ARTS) with simultaneous change in cognition for older African Americans

At autopsy, African American decedents often have mixed Alzheimer's and cerebrovascular brain pathologies including arteriolosclerosis. We applied a novel in-vivo classifier of ARTerioloSclerosis (ARTS) in 167 older African Americans (∼75y of age) with > 2 biennial 3 T MRI scans and > 3 years of associated cognitive follow-up to determine if ARTS scores (higher score=higher likelihood of arteriolosclerosis) changed over time and if this change associated with changes in cognition in the same individuals. Mixed effects regression models tested whether ARTS scores increased over time, while simultaneous mixed effects regression models estimated the simultaneous rates of change in both ARTS and cognition and the correlation of these changes. ARTS scores increased over time (estimate=0.030, SE=0.002, p < 0.0001). Faster increases in ARTS were associated with faster rates of global cognitive decline (r = -0.447, p = 0.006) and domain-specific cognitive functions. Applying an in-vivo marker of arteriolosclerosis in an African American cohort revealed that the likelihood of arteriolosclerosis increases over time, and participants whose ARTS scores increased more rapidly tended to have faster than average rates of cognitive decline.

Sex-specific genetic architecture of late-life memory performance

BACKGROUND

Women demonstrate a memory advantage when cognitively healthy yet lose this advantage to men in Alzheimer's disease. However, the genetic underpinnings of this sex difference in memory performance remain unclear.

METHODS

We conducted the largest sex-aware genetic study on late-life memory to date (Nmales  = 11,942; Nfemales  = 15,641). Leveraging harmonized memory composite scores from four cohorts of cognitive aging and AD, we performed sex-stratified and sex-interaction genome-wide association studies in 24,216 non-Hispanic White and 3367 non-Hispanic Black participants.

RESULTS

We identified three sex-specific loci (rs67099044-CBLN2, rs719070-SCHIP1/IQCJ-SCHIP), including an X-chromosome locus (rs5935633-EGL6/TCEANC/OFD1), that associated with memory. Additionally, we identified heparan sulfate signaling as a sex-specific pathway and found sex-specific genetic correlations between memory and cardiovascular, immune, and education traits.

DISCUSSION

This study showed memory is highly and comparably heritable across sexes, as well as highlighted novel sex-specific genes, pathways, and genetic correlations that related to late-life memory.

HIGHLIGHTS

Demonstrated the heritable component of late-life memory is similar across sexes. Identified two genetic loci with a sex-interaction with baseline memory. Identified an X-chromosome locus associated with memory decline in females. Highlighted sex-specific candidate genes and pathways associated with memory. Revealed sex-specific shared genetic architecture between memory and complex traits.

Longitudinal change in memory performance as a strong endophenotype for Alzheimer's disease

INTRODUCTION

Although large-scale genome-wide association studies (GWAS) have been conducted on AD, few have been conducted on continuous measures of memory performance and memory decline.

METHODS

We conducted a cross-ancestry GWAS on memory performance (in 27,633 participants) and memory decline (in 22,365 participants; 129,201 observations) by leveraging harmonized cognitive data from four aging cohorts.

RESULTS

We found high heritability for two ancestry backgrounds. Further, we found a novel ancestry locus for memory decline on chromosome 4 (rs6848524) and three loci in the non-Hispanic Black ancestry group for memory performance on chromosomes 2 (rs111471504), 7 (rs4142249), and 15 (rs74381744). In our gene-level analysis, we found novel genes for memory decline on chromosomes 1 (SLC25A44), 11 (BSX), and 15 (DPP8). Memory performance and memory decline shared genetic architecture with AD-related traits, neuropsychiatric traits, and autoimmune traits.

DISCUSSION

We discovered several novel loci, genes, and genetic correlations associated with late-life memory performance and decline.

HIGHLIGHTS

Late-life memory has high heritability that is similar across ancestries. We discovered four novel variants associated with late-life memory. We identified four novel genes associated with late-life memory. Late-life memory shares genetic architecture with psychiatric/autoimmune traits.

Financial Risk Aversion Among Older Black and White Adults

OBJECTIVES

Risk aversion has a substantial impact on decision making and is associated with key demographic characteristics. However, few studies have investigated whether risk aversion varies by race.

METHODS

We investigated racial differences in financial risk aversion in 684 older Black and White adults without dementia in the Minority Aging Research Study and Rush Memory and Aging Project matched for age, education, sex, and cognition using Mahalanobis distance. We also investigated whether select contextual factors (self-reported discrimination, socioeconomic status, and literacy) mediated or affective factors (trust, loneliness, and neuroticism) moderated any observed racial differences.

RESULTS

In regression models adjusted for age, education, sex, and cognitive function, older Black adults were more risk averse than older White adults (Beta = 0.1264, standard error = 0.0227, p value ≤ .00001). None of the contextual or affective factors mediated or moderated this association.

DISCUSSION

Older Black adults are more financially risk averse than older White adults. Because risk aversion may be associated with important financial and health outcomes in older age, more research is needed to investigate the reasons for this difference.

Estimating dementia risk in an African American population using the DCTclock

The prevalence of Alzheimer's disease (AD) and related dementias (ADRD) is increasing. African Americans are twice as likely to develop dementia than other ethnic populations. Traditional cognitive screening solutions lack the sensitivity to independently identify individuals at risk for cognitive decline. The DCTclock is a 3-min AI-enabled adaptation of the well-established clock drawing test. The DCTclock can estimate dementia risk for both general cognitive impairment and the presence of AD pathology. Here we performed a retrospective analysis to assess the performance of the DCTclock to estimate future conversion to ADRD in African American participants from the Rush Alzheimer's Disease Research Center Minority Aging Research Study (MARS) and African American Clinical Core (AACORE). We assessed baseline DCTclock scores in 646 participants (baseline median age = 78.0 ± 6.4, median years of education = 14.0 ± 3.2, 78% female) and found significantly lower baseline DCTclock scores in those who received a dementia diagnosis within 3 years. We also found that 16.4% of participants with a baseline DCTclock score less than 60 were significantly more likely to develop dementia in 5 years vs. those with the highest DCTclock scores (75-100). This research demonstrates the DCTclock's ability to estimate the 5-year risk of developing dementia in an African American population. Early detection of elevated dementia risk using the DCTclock could provide patients, caregivers, and clinicians opportunities to plan and intervene early to improve cognitive health trajectories. Early detection of dementia risk can also enhance participant selection in clinical trials while reducing screening costs.

Under-Diagnosis of Dementia with Lewy Bodies in Individuals Racialized as Black: Hypotheses Regarding Potential Contributors

Dementia with Lewy bodies (DLB) is one of the most common degenerative dementias after Alzheimer's disease (AD) dementia. DLB is under-diagnosed across populations but may be particularly missed in older Black adults. The object of this review was to examine key features of DLB and potential associations with race in order to hypothesize why DLB may be under-diagnosed in Black adults in the U.S. In terms of dementia, symptoms associated with high rates of co-pathology (e.g., AD, vascular disease) in older Black adults may obscure the clinical picture that might suggest Lewy body pathology. Research also suggests that clinicians may be predisposed to give AD dementia diagnoses to Black adults, potentially missing contributions of Lewy body pathology. Hallucinations in Black adults may be misattributed to AD or primary psychiatric disease rather than Lewy body pathology. Research on the prevalence of REM sleep behavior in diverse populations is lacking, but REM sleep behavior disorder could be under-diagnosed in Black adults due to sleep patterns or reporting by caregivers who are not bed partners. Recognition of parkinsonism could be reduced in Black adults due to clinician biases, cultural effects on self-report, and potentially underlying differences in the frequency of parkinsonism. These considerations are superimposed on structural and systemic contributions to health (e.g., socioeconomic status, education, structural racism) and individual-level social exposures (e.g., social interactions, discrimination). Improving DLB recognition in Black adults will require research to investigate reasons for diagnostic disparities and education to increase identification of core symptoms in this population.

Identification of Dementia in Medicare Claims Compared to Rigorous Clinical Assessments in African Americans

BACKGROUND

Evidence indicates the health care system disproportionately misses dementia in African American compared to White individuals. In preliminary data, we examined factors related to dementia identification by the health care system among African Americans.

METHODS

We leveraged linked Medicare fee-for-service claims and detailed annual cohort evaluations in African Americans from 4 cohorts at Rush Alzheimer's Disease Center.

RESULTS

Among 88 African Americans with cognitive impairment (mean = 10 years follow-up), Medicare claims identified dementia <2 years from cohort diagnosis in 55%; 27% were identified 2-9.9 years after cohort diagnosis, and in 18% there was either no claims diagnosis during the study period, or claims identified dementia 10+ years after cohort diagnosis. Claims identification of dementia was related to older age at cohort diagnosis (eg, <2 years between cohort and claims: mean = 82 years; 10+ years/no diagnosis: mean = 77 years, p = .04), lower Mini-Mental State Examination (MMSE) score (<2 years: mean = 24; 10+ years/no diagnosis: mean = 26, p = .04), more depressive symptoms (<2 years: mean = 2.1 symptoms; 10+ years/no diagnosis: mean = 1.2, p = .04), and more comorbidity (<2 years: mean = 5.6 comorbidities; 10+ years/no diagnosis, mean = 3.0, p = .02).

CONCLUSIONS

Among African Americans, preliminary data indicate the health care system most rapidly identifies dementia in older individuals, with worse cognitive and physical health. The health care system may miss opportunities for early support of African Americans with dementia, and caregivers.

The Effects of Midlife Acute and Chronic Stressors on Black-White Differences in Cognitive Decline

OBJECTIVES

Midlife stressors may be particularly consequential for cognitive performance and disparities in cognitive decline. This study examined Black-White differences in trajectories of cognition among middle-aged adults and the effects of acute and chronic stressors on these trajectories.

METHODS

Data come from 4,011 cognitively healthy individuals aged 51-64 (620 Black and 3,391 White) who participated in the 2006-2018 waves of the Health and Retirement Study. Stressors included a count of recent life events and measures of financial strain and everyday discrimination. Global cognition was assessed using a modified version of the Telephone Interview for Cognitive Status. Linear mixed models with random slopes and intercepts assessed change in cognition over time. Race-by-time, race-by-stressor, time-by-stressor, and race-by-stressor-by-time interactions were assessed as were quadratic terms for time and each stressor.

RESULTS

After adjusting for sociodemographic, health behaviors, and health-related factors, Black respondents had lower initial cognitive performance scores (b = -1.75, p < .001) but experienced earlier but slower decline in cognitive performance over time (Black × Time2 interaction: b = 0.02, p < .01). Financial strain, discrimination, and recent life events each had distinct associations with cognitive performance but did not influence racial differences in levels of or change in cognition over time.

DISCUSSION

Middle-aged Black adults have lower initial cognition levels and experience earlier but less accelerated cognitive decline compared to White middle-aged adults. Midlife acute and chronic stressors influence baseline cognition but do so in different ways. Future research should examine the influence of other stressors on racial differences in cognitive decline at other points in the life course.

Race and sex differences in the longitudinal changes in multidimensional self-reported sleep health characteristics in aging older adults

OBJECTIVES

We examined within-individual changes in self-reported sleep health as community-dwelling older adults age as well as potential differences in these changes by self-reported sex and racial identity.

METHODS

Participants were from the United States and enrolled in the Rush Memory and Aging Project, Minority Aging Research Study, or Religious Orders Study (N = 3539, 20% Black, 75% female, mean 78years [range 65-103]), and they received annual, in-person clinical evaluations (median 5 visits [range 1-27]). A sleep health composite score measured the number of poor sleep characteristics among satisfaction, daytime sleepiness, efficiency, and duration. Mixed effects models estimated associations of age, race, sex, and their interactions on the composite and individual sleep measures, accounting for key confounders.

RESULTS

As they aged, Black participants shifted from reporting two poor sleep characteristics to one poor sleep characteristic, while White participants shifted from one poor characteristic to two. Regardless of age, sex, and race, participants reported that they "often" felt satisfied with their sleep and "sometimes" had trouble staying asleep. Females over age 85 and males of all ages reported the most daytime sleepiness, and older White participants (>age 90) reported the most difficulty falling asleep.

CONCLUSIONS

Although self-reported sleep characteristics were typically stable across age, identifying race and sex differences in self-reported sleep health can help guide future research to understand the mechanisms that underlie these differences.

High-throughput digital quantification of Alzheimer disease pathology and associated infrastructure in large autopsy studies

High-throughput digital pathology offers considerable advantages over traditional semiquantitative and manual methods of counting pathology. We used brain tissue from 5 clinical-pathologic cohort studies of aging; the Religious Orders Study, the Rush Memory and Aging Project, the Minority Aging Research Study, the African American Clinical Core, and the Latino Core to (1) develop a workflow management system for digital pathology processes, (2) optimize digital algorithms to quantify Alzheimer disease (AD) pathology, and (3) harmonize data statistically. Data from digital algorithms for the quantification of β-amyloid (Aβ, n = 413) whole slide images and tau-tangles (n = 639) were highly correlated with manual pathology data (r = 0.83 to 0.94). Measures were robust and reproducible across different magnifications and repeated scans. Digital measures for Aβ and tau-tangles across multiple brain regions reproduced established patterns of correlations, even when samples were stratified by clinical diagnosis. Finally, we harmonized newly generated digital measures with historical measures across multiple large autopsy-based studies. We describe a multidisciplinary approach to develop a digital pathology pipeline that reproducibly identifies AD neuropathologies, Aβ load, and tau-tangles. Digital pathology is a powerful tool that can overcome critical challenges associated with traditional microscopy methods.

What is the association between adverse childhood experiences and late-life cognitive decline? Study of Healthy Aging in African Americans (STAR) cohort study

OBJECTIVES

Adverse childhood experiences (ACEs) are associated with higher risk of chronic disease, but little is known about the association with late life cognitive decline. We examined the longitudinal association between ACEs and late-life cognitive decline in the Study of Healthy Aging in African Americans (STAR).

DESIGN

Linear mixed models with random intercepts and slope examined the association of individual and composite ACEs with cognitive change adjusting for years from baseline (timescale), baseline age, sex, parental education, childhood socioeconomic status and childhood social support. Participants reported whether they had experienced nine types of ACEs. Executive function and verbal episodic memory were measured up to three times over a 3-year period using the Spanish and English Neuropsychological Assessment Scales.

SETTINGS

Kaiser Permanente Northern California members living in the Bay Area.

PARTICIPANTS

STAR is a cohort study of cognitive ageing launched in 2018 that has enrolled 764 black Americans ages ≥50 years (mean age=67.5; SD=8.5).

RESULTS

Twenty-one per cent of participants reported no ACEs, 24% one ACE, 20% two ACEs, 17% three ACEs and 17% four or more ACEs. Compared with no ACEs, two ACEs (β=0.117; 95% CI 0.052 to 0.182), three ACEs (β=0.075; 95% CI 0.007 to 0.143) and four or more ACEs (β=0.089; 95% CI 0.002 to 0.158) were associated with less decline in executive function. There were no significant associations between number of ACEs and baseline or longitudinal verbal episodic memory or between individual ACEs and executive function or verbal episodic memory.

CONCLUSION

In this cohort of older black Americans, there was no association between ACEs and baseline cognition or cognitive change in verbal episodic memory; however, experiencing ≥ 2 ACEs was associated with less decline in executive function. These results may indicate that participants who survived to age 50+ and experienced ACEs may have cognitive resilience that warrants further investigation.

Differences in Life Space Activity Patterns Between Older Adults With Mild Cognitive Impairment Living Alone or as a Couple: Cohort Study Using Passive Activity Sensing

BACKGROUND

Measuring function with passive in-home sensors has the advantages of real-world, objective, continuous, and unobtrusive measurement. However, previous studies have focused on 1-person homes only, which limits their generalizability.

OBJECTIVE

This study aimed to compare the life space activity patterns of participants living alone with those of participants living as a couple and to compare people with mild cognitive impairment (MCI) with cognitively normal participants in both 1- and 2-person homes.

METHODS

Passive infrared motion sensors and door contact sensors were installed in 1- and 2-person homes with cognitively normal residents or residents with MCI. A home was classified as an MCI home if at least 1 person in the home had MCI. Time out of home (TOOH), independent life space activity (ILSA), and use of the living room, kitchen, bathroom, and bedroom were calculated. Data were analyzed using the following methods: (1) daily averages over 4 weeks, (2) hourly averages (time of day) over 4 weeks, or (3) longitudinal day-to-day changes.

RESULTS

In total, 129 homes with people living alone (n=27, 20.9%, MCI and n=102, 79.1%, no-MCI homes) and 52 homes with people living as a couple (n=24, 46.2%, MCI and n=28, 53.8%, no-MCI homes) were included with a mean follow-up of 719 (SD 308) days. Using all 3 analysis methods, we found that 2-person homes showed a shorter TOOH, a longer ILSA, and shorter living room and kitchen use. In MCI homes, ILSA was higher in 2-person homes but lower in 1-person homes. The effects of MCI status on other outcomes were only found when using the hourly averages or longitudinal day-to-day changes over time, and they depended on the household type (alone vs residing as a couple).

CONCLUSIONS

This study shows that in-home behavior is different when a participant is living alone compared to when they are living as a couple, meaning that the household type should be considered when studying in-home behavior. The effects of MCI status can be detected with in-home sensors, even in 2-person homes, but data should be analyzed on an hour-to-hour basis or longitudinally.

The association of perceived discrimination with dementia risk in Black older adults

INTRODUCTION

Non-Hispanic Black, compared to non-Hispanic White, older adults are at increased risk for dementia. This may be due partly to greater exposure to psychosocial stressors, such as discrimination; however, few studies have examined this association.

METHODS

We examined the association of perceived discrimination (e.g., everyday, lifetime, and discrimination burden) with dementia risk in 1583 Black adults co-enrolled in the Atherosclerosis Risk in Communities (ARIC) Study and the Jackson Heart Study (JHS). Perceived discrimination (defined continuously and using tertiles) was assessed at JHS Exam 1 (2000-2004; mean age ± SD:66.2 ± 5.5) and related to dementia risk through ARIC visit 6 (2017) using covariate-adjusted Cox proportional hazards models.

RESULTS

Associations of perceived everyday, lifetime, and burden of discrimination with dementia risk were not supported in age-adjusted models or demographic- and cardiovascular health-adjusted models. Results were similar across sex, income, and education.

DISCUSSION

In this sample, associations between perceived discrimination and dementia risk were not supported.

HIGHLIGHTS

In Black older adults perceived discrimination not associated with dementia risk. Younger age and greater education linked to greater perceived discrimination. Older age and less education among factors associated with dementia risk. Factors increasing exposure to discrimination (education) are also neuroprotective.

Sex differences in associations between APOE ε2 and longitudinal cognitive decline

INTRODUCTION

We examined whether sex modifies the association between APOE ε2 and cognitive decline in two independent samples.

METHODS

We used observational data from cognitively unimpaired non-Hispanic White (NHW) and non-Hispanic Black (NHB) adults. Linear mixed models examined interactive associations of APOE genotype (ε2 or ε4 carrier vs. ε3/ε3) and sex on cognitive decline in NHW and NHB participants separately.

RESULTS

In both Sample 1 (N = 9766) and Sample 2 (N = 915), sex modified the association between APOE ε2 and cognitive decline in NHW participants. Specifically, relative to APOE ε3/ε3, APOE ε2 protected against cognitive decline in men but not women. Among APOE ε2 carriers, men had slower decline than women. Among APOE ε3/ε3 carriers, cognitive trajectories did not differ between sexes. There were no sex-specific associations of APOE ε2 with cognition in NHB participants (N = 2010).

DISCUSSION

In NHW adults, APOE ε2 may protect men but not women against cognitive decline.

HIGHLIGHTS

We studied sex-specific apolipoprotein E (APOE) ε2 effects on cognitive decline. In non-Hispanic White (NHW) adults, APOE ε2 selectively protects men against decline. Among men, APOE ε2 was more protective than APOE ε3/ε3. In women, APOE ε2 was no more protective than APOE ε3/ε3. Among APOE ε2 carriers, men had slower decline than women. There were no sex-specific APOE ε2 effects in non-Hispanic Black (NHB) adults.

Pragmatic approaches to handling practice effects in longitudinal cognitive aging research

INTRODUCTION

The challenge of accounting for practice effects (PEs) when modeling cognitive change was amplified by the COVID-19 pandemic, which introduced period and mode effects that may bias the estimation of cognitive trajectory.

METHODS

In three Kaiser Permanente Northern California prospective cohorts, we compared predicted cognitive trajectories and the association of grip strength with cognitive decline using three approaches: (1) no acknowledgment of PE, (2) inclusion of a wave indicator, and (3) constraining PE based on a preliminary model (APM) fit using a subset of the data.

RESULTS

APM-based correction for PEs based on balanced, pre-pandemic data, and with current age as the timescale produced the smallest discrepancy between within-person and between-person estimated age effects. Estimated associations between grip strength and cognitive decline were not sensitive to the approach used.

DISCUSSION

Constraining PEs based on a preliminary model is a flexible, pragmatic approach allowing for meaningful interpretation of cognitive change.

HIGHLIGHTS

The magnitude of practice effects (PEs) varied widely by study. When PEs were present, the three PE approaches resulted in divergent estimated age-related cognitive trajectories. Estimated age-related cognitive trajectories were sometimes implausible in models that did not account for PEs. The associations between grip strength and cognitive decline did not differ by the PE approach used. Constraining PEs based on estimates from a preliminary model allows for a meaningful interpretation of cognitive change.

Neuropathologic correlates of cerebral microbleeds in community-based older adults

Cerebral microbleeds (CMBs) appearing as hypointense foci on T2*-weighted magnetic resonance images are small hemorrhages that have been linked to cognitive decline and increased mortality. However, the neuropathologic correlates of CMBs in community-based older adults are poorly understood. The present study investigated the association of age-related neuropathologies with CMBs in community-based older adults. Cerebral hemispheres from 289 participants of the Rush Memory and Aging Project, Religious Orders Study, Minority Aging Research Study, and Rush Alzheimer's Disease Clinical Core underwent ex vivo MRI and detailed neuropathologic examination. Following Bonferroni correction, CMBs in the cerebrum overall and in the frontal lobe were associated with cerebral amyloid angiopathy, CMBs in the frontal lobe were also associated with arteriolosclerosis, and CMBs in the basal ganglia showed a borderline significant association with microinfarcts. These findings suggest that CMBs can aid in the prediction of small vessel disease in community-based older adults. Finally, CMBs were not associated with dementia, suggesting that CMBs in community-based older adults may not be linked to substantial cognitive impairment.

Associations of Sex, Race, and Apolipoprotein E Alleles With Multiple Domains of Cognition Among Older Adults

Importance

Sex differences are established in associations between apolipoprotein E (APOE) ε4 and cognitive impairment in Alzheimer disease (AD). However, it is unclear whether sex-specific cognitive consequences of APOE are consistent across races and extend to the APOE ε2 allele.

Objective

To investigate whether sex and race modify APOE ε4 and ε2 associations with cognition.

Design, Setting, and Participants

This genetic association study included longitudinal cognitive data from 4 AD and cognitive aging cohorts. Participants were older than 60 years and self-identified as non-Hispanic White or non-Hispanic Black (hereafter, White and Black). Data were previously collected across multiple US locations from 1994 to 2018. Secondary analyses began December 2021 and ended September 2022.

Main Outcomes and Measures

Harmonized composite scores for memory, executive function, and language were generated using psychometric approaches. Linear regression assessed interactions between APOE ε4 or APOE ε2 and sex on baseline cognitive scores, while linear mixed-effect models assessed interactions on cognitive trajectories. The intersectional effect of race was modeled using an APOE × sex × race interaction term, assessing whether APOE × sex interactions differed by race. Models were adjusted for age at baseline and corrected for multiple comparisons.

Results

Of 32 427 participants who met inclusion criteria, there were 19 007 females (59%), 4453 Black individuals (14%), and 27 974 White individuals (86%); the mean (SD) age at baseline was 74 years (7.9). At baseline, 6048 individuals (19%) had AD, 4398 (14%) were APOE ε2 carriers, and 12 538 (38%) were APOE ε4 carriers. Participants missing APOE status were excluded (n = 9266). For APOE ε4, a robust sex interaction was observed on baseline memory (β = -0.071, SE = 0.014; P = 9.6 × 10-7), whereby the APOE ε4 negative effect was stronger in females compared with males and did not significantly differ among races. Contrastingly, despite the large sample size, no APOE ε2 × sex interactions on cognition were observed among all participants. When testing for intersectional effects of sex, APOE ε2, and race, an interaction was revealed on baseline executive function among individuals who were cognitively unimpaired (β = -0.165, SE = 0.066; P = .01), whereby the APOE ε2 protective effect was female-specific among White individuals but male-specific among Black individuals.

Conclusions and Relevance

In this study, while race did not modify sex differences in APOE ε4, the APOE ε2 protective effect could vary by race and sex. Although female sex enhanced ε4-associated risk, there was no comparable sex difference in ε2, suggesting biological pathways underlying ε4-associated risk are distinct from ε2 and likely intersect with age-related changes in sex biology.

Trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons

BACKGROUND

Findings from observational studies suggest that dietary patterns may offer protective benefits against cognitive decline, but data from clinical trials are limited. The Mediterranean-DASH Intervention for Neurodegenerative Delay, known as the MIND diet, is a hybrid of the Mediterranean diet and the DASH (Dietary Approaches to Stop Hypertension) diet, with modifications to include foods that have been putatively associated with a decreased risk of dementia.

METHODS

We performed a two-site, randomized, controlled trial involving older adults without cognitive impairment but with a family history of dementia, a body-mass index (the weight in kilograms divided by the square of the height in meters) greater than 25, and a suboptimal diet, as determined by means of a 14-item questionnaire, to test the cognitive effects of the MIND diet with mild caloric restriction as compared with a control diet with mild caloric restriction. We assigned the participants in a 1:1 ratio to follow the intervention or the control diet for 3 years. All the participants received counseling regarding adherence to their assigned diet plus support to promote weight loss. The primary end point was the change from baseline in a global cognition score and four cognitive domain scores, all of which were derived from a 12-test battery. The raw scores from each test were converted to z scores, which were averaged across all tests to create the global cognition score and across component tests to create the four domain scores; higher scores indicate better cognitive performance. The secondary outcome was the change from baseline in magnetic resonance imaging (MRI)-derived measures of brain characteristics in a nonrandom sample of participants.

RESULTS

A total of 1929 persons underwent screening, and 604 were enrolled; 301 were assigned to the MIND-diet group and 303 to the control-diet group. The trial was completed by 93.4% of the participants. From baseline to year 3, improvements in global cognition scores were observed in both groups, with increases of 0.205 standardized units in the MIND-diet group and 0.170 standardized units in the control-diet group (mean difference, 0.035 standardized units; 95% confidence interval, -0.022 to 0.092; P = 0.23). Changes in white-matter hyperintensities, hippocampal volumes, and total gray- and white-matter volumes on MRI were similar in the two groups.

CONCLUSIONS

Among cognitively unimpaired participants with a family history of dementia, changes in cognition and brain MRI outcomes from baseline to year 3 did not differ significantly between those who followed the MIND diet and those who followed the control diet with mild caloric restriction. (Funded by the National Institute on Aging; ClinicalTrials.gov number, NCT02817074.).

Effects of Cerebrovascular and Lewy Body Pathology on Parkinsonian Signs in Community-Dwelling Older Adults

BACKGROUND AND OBJECTIVES

The roles of Lewy body (LB) and separately of cerebrovascular disease (CVD) pathologies in the severity of parkinsonian signs are well recognized in old age. We investigated whether the 2 pathologies act synergistically to further potentiate the severity of parkinsonism beyond their separate effects.

METHODS

We used postmortem data of decedents from 3 longitudinal community-based studies of aging who underwent annual clinical evaluation to assess parkinsonian signs using 26 items of the motor portion of a modified Unified Parkinson Disease Rating Scale. A summary score was developed from each item score to construct a global parkinsonian score, with a higher score indicating more severe parkinsonism. A detailed neuropathologic evaluation was performed to identify LB, Alzheimer disease pathology, nigral neuronal loss, atherosclerosis, macroscopic infarcts, and other CVD pathologies (arteriolosclerosis, cerebral amyloid angiopathy, and microscopic infarcts). A series of regression models with terms for LB, CVD pathology, and the interaction of LB with CVD pathologies was fit for global parkinsonism proximate to death and for individual parkinsonian signs scores including, parkinsonian gait, rigidity, tremor, and bradykinesia.

RESULTS

In 1,753 participants (mean age at death = 89 years; 68% women), LB was observed in 26% of participants, and CVD pathologies were present in more than two-thirds of participants. LB and 3 CVD pathologies (atherosclerosis, arteriolosclerosis, and macroscopic infarcts) were each independently associated with the severity of global parkinsonism proximate to death (LB: β = 0.318, SE = 0.08, p < 0.001; atherosclerosis: β = 0.373, SE = 0.079, p < 0.001; arteriolosclerosis: β = 0.253, SE = 0.078, p = 0.001; macroscopic infarcts: β = 0.333, SE = 0.077, p < 0.001). A linear regression model adjusted for demographics, CVD, and neurodegenerative pathologies showed interaction between LB and macroscopic infarcts (β = 0.463, SE = 0.168, p = 0.006), with LBs being associated with worse global parkinsonism when macroinfarcts are present. Similar interactions were found for atherosclerosis and LBs (β = 0.371, SE = 0.173, p = 0.032) and for parkinsonian gait as the outcome (macroscopic infarcts: β = 0.662, SE = 0.239, p = 0.005; atherosclerosis: β = 0.509, SE = 0.246, p = 0.038). Findings were not affected when the 66 participants with a clinical diagnosis of Parkinson disease were excluded. By contrast, there were no interactions between LB and other CVD pathologies or between atherosclerosis and macroscopic infarcts for global parkinsonism proximate to death.

DISCUSSION

These findings suggest that atherosclerosis and macroscopic infarcts interact with LB pathology to increase the severity of parkinsonism beyond their additive effects in older persons.

Age-related and amyloid-beta-independent tau deposition and its downstream effects

Amyloid-β (Aβ) is hypothesized to facilitate the spread of tau pathology beyond the medial temporal lobe. However, there is evidence that, independently of Aβ, age-related tau pathology might be present outside of the medial temporal lobe. We therefore aimed to study age-related Aβ-independent tau deposition outside the medial temporal lobe in two large cohorts and to investigate potential downstream effects of this on cognition and structural measures. We included 545 cognitively unimpaired adults (40-92 years) from the BioFINDER-2 study (in vivo) and 639 (64-108 years) from the Rush Alzheimer's Disease Center cohorts (ex vivo). 18F-RO948- and 18F-flutemetamol-PET standardized uptake value ratios were calculated for regional tau and global/regional Aβ in vivo. Immunohistochemistry was used to estimate Aβ load and tangle density ex vivo. In vivo medial temporal lobe volumes (subiculum, cornu ammonis 1) and cortical thickness (entorhinal cortex, Brodmann area 35) were obtained using Automated Segmentation for Hippocampal Subfields packages. Thickness of early and late neocortical Alzheimer's disease regions was determined using FreeSurfer. Global cognition and episodic memory were estimated to quantify cognitive functioning. In vivo age-related tau deposition was observed in the medial temporal lobe and in frontal and parietal cortical regions, which was statistically significant when adjusting for Aβ. This was also observed in individuals with low Aβ load. Tau deposition was negatively associated with cortical volumes and thickness in temporal and parietal regions independently of Aβ. The associations between age and cortical volume or thickness were partially mediated via tau in regions with early Alzheimer's disease pathology, i.e. early tau and/or Aβ pathology (subiculum/Brodmann area 35/precuneus/posterior cingulate). Finally, the associations between age and cognition were partially mediated via tau in Brodmann area 35, even when including Aβ-PET as covariate. Results were validated in the ex vivo cohort showing age-related and Aβ-independent increases in tau aggregates in and outside the medial temporal lobe. Ex vivo age-cognition associations were mediated by medial and inferior temporal tau tangle density, while correcting for Aβ density. Taken together, our study provides support for primary age-related tauopathy even outside the medial temporal lobe in vivo and ex vivo, with downstream effects on structure and cognition. These results have implications for our understanding of the spreading of tau outside the medial temporal lobe, also in the context of Alzheimer's disease. Moreover, this study suggests the potential utility of tau-targeting treatments in primary age-related tauopathy, likely already in preclinical stages in individuals with low Aβ pathology.

The impact of attending historically Black colleges and universities on cognitive decline in Black adults: A longitudinal analysis in the KHANDLE and STAR cohorts

INTRODUCTION

Black students attending predominantly White institutions (PWIs) versus historically Black colleges and universities (HBCUs) report more harmful discrimination and develop worse mental health outcomes, potentially offsetting the established benefits of college for lowering dementia incidence.

METHODS

Black participants in two cohorts (the Kaiser Healthy Aging and Diverse Life Experiences [KHANDLE] and the Study of Healthy Aging in African Americans [STAR]) who had attended college (N = 716) self-reported the college name (classified as HBCU vs. PWI) and completed three waves of executive function (EF) and verbal episodic memory (VEM) assessments. HBCU effects on cognitive level and decline were estimated using adjusted linear mixed-effects models.

RESULTS

HBCU (vs. PWI) attendees averaged better EF (β = 0.05 [-0.22, 0.32]) and VEM (β = 0.21 [-0.06, 0.46]) at age 70 though neither association was statistically significant. HBCU attendance was associated with slightly faster VEM decline (β = -0.03 [-0.05, 0.00]).

DISCUSSION

Harmonized analyses with larger studies are needed to estimate important effects of HBCU attendance.

HIGHLIGHTS

Higher education is robustly linked to lower dementia risk, yet Black-White inequities persist among college-educated adults. Black students attending predominantly White institutions (PWIs) versus historically Black colleges and universities (HBCUs) report more harmful discrimination and develop worse mental health outcomes, which may offset the established benefits of college for lowering dementia incidence. HBCU (vs. non-HBCU) attendees averaged better executive function and verbal episodic memory (VEM) at average age 70, though confidence intervals were wide and associations were not statistically significant, and averaged slightly faster decline in VEM. Harmonized analyses using larger nationally representative studies are likely needed to avoid underestimating the health effects of HBCU attendance.

Quantification of race/ethnicity representation in Alzheimer's disease neuroimaging research in the USA: a systematic review

BACKGROUND

Racial and ethnic minoritized groups are disproportionately at risk for Alzheimer's Disease (AD), but are not sufficiently recruited in AD neuroimaging research in the United States. This is important as sample composition impacts generalizability of findings, biomarker cutoffs, and treatment effects. No studies have quantified the breadth of race/ethnicity representation in the AD literature.

METHODS

This review identified median race/ethnicity composition of AD neuroimaging US-based research samples available as free full-text articles on PubMed. Two types of published studies were analyzed: studies that directly report race/ethnicity data (i.e., direct studies), and studies that do not report race/ethnicity but used data from a cohort study/database that does report this information (i.e., indirect studies).

RESULTS

Direct studies (n = 719) have median representation of 88.9% white or 87.4% Non-Hispanic white, 7.3% Black/African American, and 3.4% Hispanic/Latino ethnicity, with 0% Asian American, Native Hawaiian/Pacific Islander, and American Indian/Alaska Native, Multiracial, and Other Race participants. Cohort studies/databases (n = 44) from which indirect studies (n = 1745) derived are more diverse, with median representation of 84.2% white, 83.7% Non-Hispanic white, 11.6% Black/African American, 4.7% Hispanic/Latino, and 1.75% Asian American participants. Notably, 94% of indirect studies derive from just 10 cohort studies/databases. Comparisons of two time periods using a median split for publication year, 1994-2017 and 2018-2022, indicate that sample diversity has improved recently, particularly for Black/African American participants (3.39% from 1994-2017 and 8.29% from 2018-2022).

CONCLUSIONS

There is still underrepresentation of all minoritized groups relative to Census data, especially for Hispanic/Latino and Asian American individuals. The AD neuroimaging literature will benefit from increased representative recruitment of ethnic/racial minorities. More transparent reporting of race/ethnicity data is needed.

Multi-ancestry genome-wide meta-analysis of 56,241 individuals identifies LRRC4C, LHX5-AS1 and nominates ancestry-specific loci PTPRK , GRB14 , and KIAA0825 as novel risk loci for Alzheimer's disease: the Alzheimer's Disease Genetics Consortium

Limited ancestral diversity has impaired our ability to detect risk variants more prevalent in non-European ancestry groups in genome-wide association studies (GWAS). We constructed and analyzed a multi-ancestry GWAS dataset in the Alzheimer's Disease (AD) Genetics Consortium (ADGC) to test for novel shared and ancestry-specific AD susceptibility loci and evaluate underlying genetic architecture in 37,382 non-Hispanic White (NHW), 6,728 African American, 8,899 Hispanic (HIS), and 3,232 East Asian individuals, performing within-ancestry fixed-effects meta-analysis followed by a cross-ancestry random-effects meta-analysis. We identified 13 loci with cross-ancestry associations including known loci at/near CR1 , BIN1 , TREM2 , CD2AP , PTK2B , CLU , SHARPIN , MS4A6A , PICALM , ABCA7 , APOE and two novel loci not previously reported at 11p12 ( LRRC4C ) and 12q24.13 ( LHX5-AS1 ). Reflecting the power of diverse ancestry in GWAS, we observed the SHARPIN locus using 7.1% the sample size of the original discovering single-ancestry GWAS (n=788,989). We additionally identified three GWS ancestry-specific loci at/near ( PTPRK ( P =2.4×10 -8 ) and GRB14 ( P =1.7×10 -8 ) in HIS), and KIAA0825 ( P =2.9×10 -8 in NHW). Pathway analysis implicated multiple amyloid regulation pathways (strongest with P adjusted =1.6×10 -4 ) and the classical complement pathway ( P adjusted =1.3×10 -3 ). Genes at/near our novel loci have known roles in neuronal development ( LRRC4C, LHX5-AS1 , and PTPRK ) and insulin receptor activity regulation ( GRB14 ). These findings provide compelling support for using traditionally-underrepresented populations for gene discovery, even with smaller sample sizes.

Evaluating interpersonal discrimination and depressive symptoms as partial mediators of the effects of education on cognition: Evidence from the Study of Healthy Aging in African Americans (STAR)

INTRODUCTION

Education is correlated with positive health outcomes, but associations are sometimes weaker among African Americans. The extent to which exposure to discrimination and depressive symptoms attenuates the education-cognition link has not been investigated.

METHODS

Study of Healthy Aging in African Americans (STAR) participants (n = 764; average age 69 years) completed the Spanish and English Neuropsychological Assessment Scales. We assessed everyday and major lifetime discrimination and depressive symptoms as mediators of education effects on cognition using G-estimation with measurement error corrections.

RESULTS

Education was correlated with greater major lifetime and everyday discrimination but lower depressive symptoms. Accounting for discrimination and depressive symptoms slightly reduced the estimated effect of education on cognition. The estimated total effect of graduate education (vs 

DISCUSSION

Education has robust effects on later-life cognition after controlling multiple mediating pathways and offsetting mechanisms.

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Key Words

• African Americans
• cognition
• depression
• discrimination
• education
• psychosocial stress

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MESH Headings

• Aged
• Humans
• Black or African American
• Cognition
• Depression/psychology
• Educational Status
• Healthy Aging
• Racism/ethnology
• Racism/psychology

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Grants

• R01 AG066132 NIA NIH HHS
• R01 AG050782 NIA NIH HHS
• RF1 AG050782 NIA NIH HHS
• P30 AG072972 NIA NIH HHS
• R00 AG073457 NIA NIH HHS

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Affiliation(s)

Dakota W. Cintron Center for Health and Community, University of California, San Francisco, San Francisco, CA Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
Camilla Calmasini Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
Lisa L. Barnes Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL, USA Department of Neurology, Rush University Medical Center, Chicago, IL, USA
Dan M. Mungas Department of Neurology, University of California Davis Health, Sacramento, CA, USA
Rachel A. Whitmer Department of Public Health Sciences, University of California Davis, Davis, CA, USA Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA
Chloe W. Eng Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
Paola Gilsanz Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA
Kristen M. George Department of Neurology, University of California Davis Health, Sacramento, CA, USA Department of Public Health Sciences, University of California Davis, Davis, CA, USA
Rachel Peterson Department of Neurology, University of California Davis Health, Sacramento, CA, USA Department of Public Health Sciences, University of California Davis, Davis, CA, USA
M. Maria Glymour Center for Health and Community, University of California, San Francisco, San Francisco, CA Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA

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Association of Mediterranean-DASH Intervention for Neurodegenerative Delay and Mediterranean Diets With Alzheimer Disease Pathology

BACKGROUND AND OBJECTIVES

Diet may reduce Alzheimer dementia risk and slow cognitive decline, but the understanding of the relevant neuropathologic mechanisms remains limited. The association of dietary patterns with Alzheimer disease (AD) pathology has been suggested using neuroimaging biomarkers. This study examined the association of Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) and Mediterranean dietary patterns with β-amyloid load, phosphorylated tau tangles, and global AD pathology in postmortem brain tissue of older adults.

METHODS

Autopsied participants of the Rush Memory and Aging Project with complete dietary information (collected through a validated food frequency questionnaire) and AD pathology data (β-amyloid load, phosphorylated tau tangles, and global AD pathology [summarized neurofibrillary tangles and neuritic and diffuse plaques]) were included in this study. Linear regression models controlled for age at death, sex, education, APOE-ε4 status, and total calories were used to investigate the dietary patterns (MIND and Mediterranean diets) and dietary components associated with AD pathology. Further effect modification was tested for APOE-ε4 status and sex.

RESULTS

Among our study participants (N = 581, age at death: 91.0 ± 6.3 years; mean age at first dietary assessment: 84.2 ± 5.8 years; 73% female; 6.8 ± 3.9 years of follow-up), dietary patterns were associated with lower global AD pathology (MIND: β = -0.022, p = 0.034, standardized β = -2.0; Mediterranean: β = -0.007, p = 0.039, standardized β = -2.3) and specifically less β-amyloid load (MIND: β = -0.068, p = 0.050, standardized β = -2.0; Mediterranean: β = -0.040, p = 0.004, standardized β = -2.9). The findings persisted when further adjusted for physical activity, smoking, and vascular disease burden. The associations were also retained when participants with mild cognitive impairment or dementia at the baseline dietary assessment were excluded. Those in the highest tertile of green leafy vegetables intake had less global AD pathology when compared with those in the lowest tertile (tertile 3 vs tertile 1: β = -0.115, p = 0.0038).

DISCUSSION

The MIND and Mediterranean diets are associated with less postmortem AD pathology, primarily β-amyloid load. Among dietary components, higher green leafy vegetable intake was associated with less AD pathology.

Neighborhood-level social vulnerability and individual-level cognitive and motor functioning over time in older non-Latino Black and Latino adults

Introduction

Despite known health disparities in cognitive aging, a comprehensive rationale for the increased burden in older minoritized populations including non-Latino Black and Latino adults has yet to be elucidated. While most work has focused on person-specific risk, studies are increasingly assessing neighborhood-level risk. We evaluated multiple aspects of the environmental milieu that may be critical when considering vulnerability to adverse health outcomes.

Methods

We investigated associations between a Census-tract derived Social Vulnerability Index (SVI) and level of and change in cognitive and motor functioning in 780 older adults (590 non-Latino Black adults, ∼73 years old at baseline; 190 Latinos, ∼70 years old baseline). Total SVI scores (higher = greater neighborhood-level vulnerability) were combined with annual evaluations of cognitive and motor functioning (follow-up ranged from 2 to 18 years). Demographically-adjusted mixed linear regression models tested for associations between SVI and cognitive and motor outcomes in analyses stratified by ethno-racial group.

Results

For non-Latino Black participants, higher SVI scores were associated with lower levels of global cognitive and motor functioning-specifically, episodic memory, motor dexterity and gait-as well as longitudinal change in visuospatial abilities and hand strength. For Latinos, higher SVI scores were associated with lower levels of global motor functioning only-specifically, motor dexterity; there were no significant associations between SVI and change in motor functioning.

Discussion

Neighborhood-level social vulnerability is associated with cognitive and motor functioning in non-Latino Black and Latino older adults, although associations appear to contribute to level more so than longitudinal change.

Overcoming Pandemic-Related Challenges in Recruitment and Screening: Strategies and Representation of Older Women With Cardiovascular Disease for a Multidomain Lifestyle Trial to Prevent Cognitive Decline

BACKGROUND

Recruiting participants with cardiovascular disease into research during the COVID-19 pandemic was challenging, particularly those at risk of health disparities.

OBJECTIVE

During the pandemic, 12 cohorts of older women with cardiovascular disease were recruited from cardiology clinics into a lifestyle intervention trial to prevent cognitive decline. Objectives were to (a) describe the results of modified recruitment/screening strategies to overcome pandemic-related challenges and (b) evaluate differences in age, race, and ethnicity between patients recruited/randomized, recruited/not randomized (entered recruitment but not randomized because of being ineligible or not interested), and not recruited (clinic patients who met preliminary criteria but did not enter recruitment).

METHODS

This was a cross-sectional descriptive analysis. In-person study strategies proposed before the COVID-19 pandemic were modified before study onset (September 2020). Women 65 years or older with cardiovascular disease were recruited from cardiology clinics by clinicians, posted flyers, and letters mailed to patients randomly selected from electronic health record data extractions. Patients were classified as recruited/randomized, recruited/not randomized, and not recruited.

RESULTS

Of 5719 patients potentially eligible, 1689 patients entered recruitment via referral (49.1%), posted flyers (0.5%), or mailed letters (50.3%), and 253 patients were successfully recruited/randomized. Recruited/randomized participants were, on average, 72.4 years old (range, 65-90 years old), non-Hispanic White (54.2%), non-Hispanic Black (38.3%), Hispanic/Latinx (1.6%), and other/not reported (5.1%). The recruited/randomized group was significantly younger with fewer patients of Hispanic/Latinx ethnicity compared with those not recruited.

CONCLUSIONS

During the pandemic, all recruitment/screening goals were met using modified strategies. Differences in sociodemographic representation indicate a need for tailored strategies.

Late-life depressive symptoms and white matter structural integrity within older Black adults

Introduction

Older Black adults experience a high burden of depressive symptoms and cerebrovascular disease but the specific neurobiological substrates underlying the association between late-life depressive symptoms and brain integrity are understudied, particularly in within-group designs.

Methods

Using the Center for Epidemiologic Studies Depression Scale and diffusion-tensor imaging, within-Black variation in the association between late-life depressive symptoms and white matter structural integrity was examined in 297 older Black participants without dementia that were enrolled across three epidemiological studies of aging and dementia. Linear regression models were used to test associations with DTI metrics (fractional anisotropy, trace of the diffusion tensor) as the outcomes and depressive symptoms as the predictor, while adjusting for age, sex, education, scanner, serotonin-reuptake inhibitor use, total volume of white-matter hyperintensities normalized by intracranial volume, and presence of white-matter hyperintensities at the voxel level.

Results

Higher level of self-reported late-life depressive symptoms was associated with greater diffusion-tensor trace (reduced white matter integrity) in connections between commissural pathways and contralateral prefrontal regions (superior and middle frontal/dorsolateral prefrontal cortex), association pathways connecting dorsolateral prefrontal cortex with insular, striatal and thalamic regions, and association pathways connecting the parietal, temporal and occipital lobes and the thalamus.

Discussion

This study demonstrated a discernable pattern of compromised white matter structural integrity underlying late-life depressive symptoms within older Black adults.

Cognitive domain harmonization and cocalibration in studies of older adults

OBJECTIVE

Studies use different instruments to measure cognitirating cognitive tests permit direct comparisons of individuals across studies and pooling data for joint analyses.

METHOD

We began our legacy item bank with data from the Adult Changes in Thought study (n = 5,546), the Alzheimer's Disease Neuroimaging Initiative (n = 3,016), the Rush Memory and Aging Project (n = 2,163), and the Religious on such as the Mini-Mental State Examination, the Alzheimer's Disease Assessment Scale-Cognitive Subscale, the Wechsler Memory Scale, and the Boston Naming Test. CocalibOrders Study (n = 1,456). Our workflow begins with categorizing items administered in each study as indicators of memory, executive functioning, language, visuospatial functioning, or none of these domains. We use confirmatory factor analysis models with data from the most recent visit on the pooled sample across these four studies for cocalibration and derive item parameters for all items. Using these item parameters, we then estimate factor scores along with corresponding standard errors for each domain for each study. We added additional studies to our pipeline as available and focused on thorough consideration of candidate anchor items with identical content and administration methods across studies.

RESULTS

Prestatistical harmonization steps such qualitative and quantitative assessment of granular cognitive items and evaluating factor structure are important steps when trying to cocalibrate cognitive scores across studies. We have cocalibrated cognitive data and derived scores for four domains for 76,723 individuals across 10 studies.

CONCLUSIONS

We have implemented a large-scale effort to harmonize and cocalibrate cognitive domain scores across multiple studies of cognitive aging. Scores on the same metric facilitate meta-analyses of cognitive outcomes across studies or the joint analysis of individual data across studies. Our systematic approach allows for cocalibration of additional studies as they become available and our growing item bank enables robust investigation of cognition in the context of aging and dementia. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Association of Early Adulthood Hypertension and Blood Pressure Change With Late-Life Neuroimaging Biomarkers

Importance

The association between hypertension developed before midlife and late-life brain health is understudied and, because of the cardioprotective benefits of estrogen before menopause, may differ by sex.

Objective

To assess the association of early adulthood hypertension and blood pressure (BP) change with late-life neuroimaging biomarkers and examine potential sex differences.

Design, Setting, and Participants

This cohort study used data from the Study of Healthy Aging in African Americans (STAR) and Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) study, which were harmonized longitudinal cohorts of racially and ethnically diverse adults aged 50 years and older from the San Francisco Bay area and Sacramento Valley in California. The STAR was conducted from November 6, 2017, to November 5, 2021, and the KHANDLE study was conducted from April 27, 2017, to June 15, 2021. The current study included 427 participants from the KHANDLE and STAR studies who received health assessments between June 1, 1964, and March 31, 1985. Regional brain volumes and white matter (WM) integrity were measured via magnetic resonance imaging between June 1, 2017, and March 1, 2022.

Exposures

Hypertension status (normotension, transition to hypertension, and hypertension) and BP change (last measure minus first measure) were assessed at 2 multiphasic health checkups (MHCs; 1964-1985) in early adulthood (ages 30-40 years).

Main Outcomes and Measures

Regional brain volumes and WM integrity were measured using 3T magnetic resonance imaging and z standardized. General linear models adjusted for potential confounders (demographic characteristics and study [KHANDLE or STAR]) were used to assess the association of hypertension and BP change with neuroimaging biomarkers. Sex interactions were tested.

Results

Among 427 participants, median (SD) ages were 28.9 (7.3) years at the first MHC, 40.3 (9.4) years at the last MHC, and 74.8 (8.0) years at neuroimaging. A total of 263 participants (61.6%) were female and 231 (54.1%) were Black. Overall, 191 participants (44.7%) had normotension, 68 (15.9%) transitioned to hypertension, and 168 (39.3%) had hypertension. Compared with participants who had normotension, those who had hypertension and those who transitioned to hypertension had smaller cerebral volumes (hypertension: β = -0.26 [95% CI, -0.41 to -0.10]; transition to hypertension: β = -0.23 [95% CI, -0.44 to -0.23]), with similar differences in cerebral gray matter volume (hypertension: β = -0.32 [95% CI, -0.52 to -0.13]; transition to hypertension: β = -0.30 [95% CI, -0.56 to -0.05]), frontal cortex volume (hypertension: β = -0.43 [95% CI, -0.63 to -0.23]; transition to hypertension: β = -0.27 [95% CI, -0.53 to 0]), and parietal cortex volume (hypertension: β = -0.22 [95% CI, -0.42 to -0.02]; transition to hypertension: β = -0.29 [95% CI, -0.56 to -0.02]). Participants with hypertension also had smaller hippocampal volume (β = -0.22; 95% CI, -0.42 to -0.02), greater ventricular volumes (lateral ventricle: β = 0.44 [95% CI, 0.25-0.63]; third ventricle: β = 0.20 [95% CI, 0.01-0.39]), larger free water volume (β = 0.35; 95% CI, 0.18-0.52), and lower fractional anisotropy (β = -0.26; 95% CI, -0.45 to -0.08) than those who had normotension. Holding hypertension status constant, a 5-mm Hg increase in systolic BP was associated with smaller temporal cortex volume (β = -0.03; 95% CI, -0.06 to -0.01), while a 5-mm Hg increase in diastolic BP was associated with smaller parietal cortex volume (β = -0.06; 95% CI, -0.10 to -0.02). The negative association of hypertension and BP change with regional brain volumes appeared stronger in men than women for some regions.

Conclusions and Relevance

In this cohort study, early adulthood hypertension and BP change were associated with late-life volumetric and WM differences implicated in neurodegeneration and dementia. Sex differences were observed for some brain regions whereby hypertension and increasing BP appeared more detrimental for men. These findings suggest that prevention and treatment of hypertension in early adulthood is important for late-life brain health, particularly among men.

Vitamin D intake and cognitive decline in Blacks and Whites: The role of diet and supplements

INTRODUCTION

To determine the role of vitamin D intake on cognitive decline among Blacks and Whites.

METHODS

Using data from the population-based Chicago Health and Aging Project, we studied 2061 Blacks and 1329 Whites with dietary vitamin D data and cognitive testing over 12 years of follow-up. Multivariable linear mixed-effects models were used to determine the association of vitamin D intake with cognitive decline.

RESULTS

Vitamin D intake, particularly dietary vitamin D, was associated with a slower rate of decline in cognitive function among Blacks. In Blacks, comparing individuals in the lowest tertile of dietary intake, those in the highest tertile had a slower cognitive decline of 0.017 units/year (95% confidence interval 0.006, 0.027), independently of supplementation use. In Whites, vitamin D intake was not associated with cognitive decline.

DISCUSSION

Dietary vitamin D may help to slow the decline in cognitive abilities among Blacks as they age.

A Longitudinal Study of Acculturation in Context and Cardiovascular Health and Their Effects on Cognition Among Older Latino Adults

Background We previously outlined the importance of considering acculturation within the context of older Latino adults' lived experience (ie, acculturation in context) to better capture contributors to cognitive aging. We now examine this conceptual framework as related to level of and change in cardiovascular health, and whether cardiovascular health modifies previously documented associations of acculturation in context with cognition. Methods and Results Acculturation in context data from 192 Latino participants without dementia at baseline (age ~70 years) were compiled into 3 separate composite scores: acculturation-related (nativity, language-, and social-based preferences), contextually related socioenvironmental (experiences of discrimination, social isolation, social networks), and familism-related (Latino-centric family ethos). A modified American Heart Association's Life's Simple 7 (mLS7; ie, smoking, physical activity, body mass index, blood pressure, total cholesterol, blood glucose) was used to measure cardiovascular health. Mixed effects regressions simultaneously tested the association of all 3 composite scores with total mLS7 adjusting for confounders. Separate models tested whether mLS7 modified associations of the 3 composite scores and cognition. The contextually related socioenvironmental composite score reflecting higher discrimination, higher social isolation, and smaller social networks (estimate=0.22, SE=0.10, P=0.02) and the familism score (estimate=0.16, SE=0.07, P=0.02) both significantly associated with change in total mLS7. The acculturation-related composite was not significantly associated with change in mLS7. No composite was significantly associated with level of mLS7. Total mLS7, however, significantly modified associations between the acculturation-related composite and change in working memory (estimate=-0.02, SE=0.01, P=0.043). Conclusions Acculturation within the context of older Latino adults' lived experience is important for maintaining cardiovascular health, relationships that also affect domain-specific cognitive decline.

Perceptions of Caring Recruitment Among Older Adults: African Americans and Non-Latinx Whites

BACKGROUND

African Americans (AAs) are underrepresented in health-related research studies. Few studies have investigated how behaviors of study recruiters affect recruitment of older AAs versus non-Latinx Whites (NLWs).

OBJECTIVES

The aim of this study was to explore whether caring behaviors influence AA and NLW older adults' decision to participate in hypothetical, high-commitment, health-related research studies and differences in participants' enrollment decisions by race.

METHODS

Using a descriptive, cross-sectional study design, guided by Kristen Swanson's middle-range theory of caring, a research-savvy sample of 60 AA and 60 NLW adults (age > 65 years) were randomly assigned one of two written vignettes. The concept of caring behaviors was manipulated and illustrated in a hypothetical recruitment scenario. A participant feedback survey was used to assess (a) participants' perceptions of caring and uncaring behaviors exhibited by the fictitious research recruiter, (b) differences in their willingness to participate based on vignette type, and (c) participants' judgment of the research recruiter as being caring or uncaring. A chi-square test assessed the association among categorical variables (caring behavior and participants' race).

RESULTS

Participants who received the vignette with the high caring recruiter were more than twice as likely to agree to participate in the study than those who received the vignette with the low caring recruiter. AA and NLW participants did not differ in their likelihood to agree to participate. Participants who received the caring vignette and judged the recruiter as caring were 5 times as likely to agree to participate in the high-commitment study than those who received the uncaring vignette ( p < .001). Associations did not vary by race.

DISCUSSION

This experimental study of equally recruited older adults from an existing longitudinal study revealed that caring behaviors in recruitment strategies are associated with an increased likelihood of participation in high-commitment research with older adults. The research-savvy AA participants were just as likely to participate in the hypothetical high-commitment research as their NLW peers when the fictional research recruiter was perceived as having caring behaviors. When targeting specific populations, it is essential to employ nuanced recruitment approaches where the study recruiters are attuned to caring behaviors.

Decision Making and Blood Sugar Indicators in Older African American Adults

Objectives: Decision making is a modifiable behavior associated with health outcomes. We investigated the association of decision making with blood sugar indicators in older community-dwelling African American adults. Methods: Participants were 328 older African American adults from community-based studies (mean age = 78). Decision making was assessed using a performance-based measure (range: 0-12). Blood sugar indicators were non-fasting hemoglobin A1c and blood glucose. Using regression, we assessed the relationship between decision making and each blood sugar indicator, controlling for demographics. We additionally examined if an association varied by known diabetes diagnosis. Results: Lower decision making was associated with higher HbA1c (b: -0.05, p-value: .03), but not blood glucose. In an interaction analysis, the association of lower decision making with higher levels of HbA1c was present only among individuals with known diabetes (b (with diabetes): -0.13, p-value: <.01). Discussion: Decision making may contribute to glycemic control in African American older adults with diabetes.

Longitudinal Changes in Blood Biomarkers of Clinical Alzheimer Disease in a Biracial Population Sample

BACKGROUND AND OBJECTIVES

Recent studies suggest the utility of blood biomarkers in detecting changes in neurodegenerative disorders. The objective of our research was to test the hypothesis that the longitudinal changes in total tau (t-tau), neurofilament light chain (Nf-L), and glial fibrillary acidic protein (GFAP) are associated with structural MRI and the development of clinical Alzheimer disease (AD) and cognitive decline.

METHODS

Data came from a population-based sample with serum concentrations of t-tau, Nf-L, and GFAP and cognitive characteristics measured over 17 years. The inclusion criteria for this investigation were based on participants with blood samples, cognitive function testing, and clinical diagnosis for AD. The longitudinal changes in the serum biomarkers were examined using linear mixed models for log10-transformed concentrations.

RESULTS

In 1,327 participants (60% Black participants and 60% women, the concentration of t-tau increased annually by 4.8% (95% CI = 4.0-5.6) and Nf-L by 5.9% (95% CI = 5.4-6.4). The longitudinal change in GFAP was higher among Black participants than among White participants (4.4% vs 3.5% per year, p = 0.028). Baseline MRI characteristics were associated with the longitudinal changes in serum biomarkers of clinical AD. Specifically, a higher baseline third ventricular volume was associated with a higher rate of increase in the concentration of t-tau, and white matter hyperintensities predicted a higher rate of increase in Nf-L. The rate of change in concentrations of t-tau, Nf-L, and GFAP was significantly higher among those who developed clinical AD than in those with no cognitive impairment. For each standard deviation unit decline in global cognition, longitudinal change in t-tau increased by 81% (95% CI = 76-86), Nf-L by 113% (95% CI = 105-120), and GFAP by 66% (95% CI = 62-70).

DISCUSSION

Blood biomarkers showed significant longitudinal changes corresponding to cognitive decline, clinical AD, and structural MRI characteristics. Our findings show that longitudinal changes in serum biomarkers were associated with several cognitive endophenotypes.

CLASSIFICATION OF EVIDENCE

The study found Class II evidence that longitudinal changes in serum t-tau, Nf-L, and GFAP were associated with cognitive decline and the development of clinical AD in people older than 65 years.

Association of Dietary Intake of Flavonols With Changes in Global Cognition and Several Cognitive Abilities

BACKGROUND AND OBJECTIVES

Previous research has examined the association between cognition and flavonoids: bioactives found in foods, known to possess anti-inflammatory and antioxidant properties. We extend this research by investigating associations of dietary intakes of total flavonols and constituents (kaempferol, quercetin, myricetin, and isorhamnetin) on the change in cognitive performance in global cognition, episodic memory, semantic memory, visuospatial ability, perceptual speed, and working memory.

METHODS

The study was conducted using 961 participants (aged 60-100 years) of the Rush Memory and Aging Project, a prospective cohort of community-dwelling Chicagoans who were followed for an average of 6.9 years. Diet was assessed using a validated semiquantitative food frequency questionnaire. Cognitive performance was assessed annually with a battery of 19 standardized tests. Flavonol intake was analyzed as a continuous variable using linear mixed-effects models. Cognitive domain scores were regressed on baseline calorie-adjusted flavonol variables.

RESULTS

Higher dietary intakes of total flavonols and flavonol constituents were associated with a slower rate of decline in global cognition and multiple cognitive domains. In continuous models adjusted for age, sex, education, APOE ɛ4, late-life cognitive activity, physical activity, and smoking, total flavonol intake was associated with slower decline in global cognition β estimate = 0.004 (95% CI 0.001-0.006), episodic memory β = 0.004 (95% CI 0.002-0.006), semantic memory β = 0.003 (95% CI 0.001-0.007), perceptual speed β = 0.003 (95% CI 0.001-0.004), and working memory β = 0.003 (95% CI 0.001-0.005) and marginally associated with visuospatial ability β = 0.001 (95% CI -0.001 to 0.003). Analyses of individual flavonol constituents demonstrated that intakes of kaempferol and quercetin were associated with slower global cognitive decline (β = 0.01 [95% CI 0.006-0.02] and β = 0.004 [95% CI 0.0005-0.007]), respectively. Myricetin and isorhamnetin were not associated with global cognition.

DISCUSSION

Results suggest that dietary intakes of total flavonols and several flavonol constituents may be associated with slower decline in global cognition and multiple cognitive abilities with older age.

A Qualitative Examination of Knowledge, Experiences, and Considerations of PET Brain Scan Participation Among Older Black and Latino Adults

BACKGROUND

Biological biomarkers yielded from positron emission tomography (PET) brain scans serve as a pathway to understanding Alzheimer's disease pathology. PET brain scan data remain limited for populations traditionally under-included in aging research.

OBJECTIVE

The purpose of this qualitative study was to examine participant-identified barriers to PET brain scan consent and characterize participant-informed elements of educational materials needed to facilitate PET brain scan participation among older Black and Latino adults.

METHODS

Participants (N = 31) were older adults (mean age = 71 years) who self-identified as either non-Latino Black (n = 15) or Latino (n = 16). Each participant took part in a one-time, in-depth individual interview. Researchers analyzed data guided by a Grounded Theory Approach with both Open Coding and Constant Comparative Coding.

RESULTS

Four overarching themes emerged across all participants: 1) knowledge limitations; 2) requirements for consent; 3) motivators for participation; and 4) social networks. Within the four themes, there were differences based on participant ethnoracial group. For example, for Theme Three, older Black adults indicated that they would expect compensation for PET brain scan participation. Conversely, older Latinos stated that they would appreciate, but not anticipate, a financial incentive. All participants stressed the importance of written educational materials with subsequent verbal discussions with studystaff.

CONCLUSION

Findings inform the development and implementation of scientifically-relevant and culturally-cognizant engagement approaches, educational materials, and recruitment strategies to increase PET brain scan participation by diverse older adults.

Acculturation in Context and Brain Health in Older Latino Adults: A Diffusion Tensor Imaging Study

BACKGROUND

Latinos are at higher risk of developing mild cognitive impairment (MCI) and Alzheimer's disease than non-Latino Whites. Acculturation factors may influence this risk, yet there are few studies that have examined associations of acculturation, particularly in the context of socioenvironmental and familial factors, and brain health in older Latinos.

OBJECTIVE

To examine potential associations between acculturation in context and brain health in older Latinos.

METHODS

Using three previously established composites of acculturation-in-context, (acculturation-related: nativity status, language preference, acculturation scores; contextually-related socioenvironmental: perceived discrimination, loneliness/social isolation, social network size; and familism), and diffusion-tensor imaging (DTI), associations with white matter structural integrity were examined in 92 Latino adults without dementia participating in one of three epidemiological studies of aging. Linear regression models were used to test associations with DTI-derived metrics (fractional anisotropy, FA; trace) as separate outcomes and acculturation composite scores as individual predictors, while adjusting for age, sex, education, scanner, and white matter hyperintensities (voxelwise and total volumes normalized by intracranial volume).

RESULTS

Higher scores on the socioenvironmental composite were associated with lower FA in two clusters of left-hemisphere connections. Cluster 1 was dominated by both short association pathways connecting frontal regions and projection pathways connecting frontal regions with the thalamus. Cluster 2 was dominated by long association pathways connecting parietal, frontal, and temporal regions.

CONCLUSIONS

This study of older Latino adults demonstrated an association between reduced brain white matter integrity and contextually related socioenvironmental experiences known to increase risk of MCI and Alzheimer's disease.