The Minority Aging Research Study: ongoing efforts to obtain brain donation in African Americans without dementia

Brain donation rules in Italy and worldwide: overview of a cutting-edge topic for human brain research

Neuropathological examination of the brain and its biochemical analyses are fundamental to neuroscience studies and public health decisions, but are dependent on the effectiveness of regulations and operational protocols. The article discusses opportunities and limits of Italian regulation on body donation in relation to the specific requirements of neuropathology and brain sciences, in comparison with the regulations of other countries. Some crucial issues emerge, widely shared in the various regulatory contexts. The main aspect is the willingness to donate, consciously expressed by the subject by signing an informed consent or through the formulation of advanced directives. The donation of a single organ, the brain in particular, does not necessarily imply the donation of the entire body, which should be considered separately. In the specific case of the brain, particular attention is given to reducing the post-mortem interval, in order to obtain tissues suitable for research. Consequently, the centres that deal with the brain and brain banking must have experience and expertise in handling nervous tissue, and do not necessarily have to deal with the management of the entire body. These aspects, still little addressed in Italy, are the basis to develop an effective brain banking activity, which can only develop by integrating post-mortem body donation with specific rules for brain banking without which Italian neuroscience will be penalised in the coming years.

Factors Associated With Healthcare and Financial Decision Making Among Older Black Adults Without Dementia

OBJECTIVES

The study aims to identify factors associated with health care and financial decision-making among older Black adults without dementia.

METHODS

Participants (N = 326) underwent assessments of decision-making and completed measurements of factors from four categories: cognitive, contextual, psychosocial, and personality. We performed separate linear regression models to examine the association between each factor and decision-making and created a fully adjusted model.

RESULTS

Higher global cognition (estimate = 1.92, SE = 0.21, p < .0001) was associated with better decision-making. Contextual factors including higher current annual income (estimate = 0.23, SE = 0.05, p < .0001), higher childhood socioeconomic status (estimate = 0.48, SE = 0.18, p = .006), higher health and financial literacy (estimate = 0.08, SE = 0.01, p < .0001), and lower financial stress (estimate = -0.19, SE = 0.07, p = .01) were associated with better decision-making. More psychological well-being (estimate = 0.07, SE = 0.22, p = .001), a psychosocial factor, and less neuroticism (estimate = -0.06, SE = 0.02, p = .002), a personality factor, were associated with better decision-making. In the fully adjusted model, two factors, higher global cognition and higher literacy (health and financial), remained associated with better decision-making.

CONCLUSIONS

Cognitive and contextual factors serve as drivers of decision-making among older Black adults.

CLINICAL IMPLICATIONS

Clinicians may implement strategies to bolster cognition and improve health and financial literacy to facilitate optimal decision-making among older Black adults.

Pathways to Racial/Ethnic Inequalities in Dementia

Individuals from minoritized racial/ethnic groups face a disproportionate burden of Alzheimer's disease and related dementias. This health inequality reflects structural racism, which creates and sustains racial differences in social determinants of health, including education access and quality, economic stability, social and community context, neighborhood and built environment, and health care access and quality. Thus, understanding pathways that lead to dementia inequalities requires addressing individual- and system-level factors. This article summarizes evidence linking each social determinant of health to racial/ethnic inequalities in dementia, emphasizing upstream factors and mechanisms as potential levels of intervention. The importance of resilience in marginalized groups as well as critical research considerations for dementia inequalities are also discussed. Future directions highlight the need to understand the common and unique mechanisms driving inequalities across minoritized groups, where research is lacking.

Cerebrovascular Pathology and Cognitive Outcomes in Older Black Decedents

BACKGROUND

Few neuropathologic studies focus on the associations of cerebrovascular pathologies with cognition in older Black adults.

METHODS

We conducted a nested substudy of participants who were enrolled in 1 of 4 harmonized longitudinal cohort studies-the Minority Aging Research Study, African American Clinical Core, Rush Memory and Aging Project, and Religious Order Study before coming to autopsy. Neuropathologic evaluation included assessment of cerebrovascular and neurodegenerative pathologies. We first documented single and mixed cerebrovascular profiles and neurodegenerative pathologies in 112 Black decedents and examined the pathological burden with cognitive function proximate to death. In secondary analyses, we matched 2:1 the 112 Black decedents to 214 White decedents from the same cohorts using Mahalanobis distance matching and conducted linear regression models to examine racial differences in the burden of each vascular pathology and their associations with cognition.

RESULTS

In older Black decedents, macroscopic infarcts were present in 37%, microinfarcts in 30%, basal ganglia arteriolosclerosis in 20%, cerebral amyloid angiopathy in 32%, and atherosclerosis in 14%. Single cerebrovascular profiles were present in 29% and mixed cerebrovascular profiles in 40%. Microinfarcts (estimate=-0.51, SE=0.23, P=0.03) and arteriolosclerosis in the basal ganglia (estimate =-0.29, SE=0.13, P=0.03) were associated with lower global cognition independent of neurodegenerative pathologies. Further, microinfarcts were associated with lower episodic and semantic memory, and perceptual speed, whereas arteriolosclerosis was associated with only semantic memory. Mixed vascular profiles were also associated with lower episodic memory and perceptual speed. In secondary analyses, the burden of cerebrovascular pathologies and cognitive associations were similar across races.

CONCLUSIONS

Cerebrovascular pathologies are common in older Black decedents, most often as a mixed cerebrovascular pathology profile. Arteriosclerosis and microinfarcts were associated with lower cognition above and beyond the presence of neurodegenerative pathologies. Burden and cognitive associations with cerebrovascular pathologies were similar across races.

Assessing Cognitive Decline and Dementia Risk in Black and White Older Adults with Blood Biomarkers pTau217, GFAP, NfL, and Aβ ratio

Background

Alzheimer's disease blood-based biomarkers are a cost-effective early-detection method that, for precision medicine reasons, needs to be studied in both Blackand White. Few studies have a long follow-up of cognition. We studied a blood-biomarkers panel, cognitive decline, and dementia risk in a large number of Black and White participants.

Methods

Participants without dementia were followed annually up to 15 years, after plasma biomarker measurement (NfL, GFAP, amyloid-beta 42/40 ratio, pTau217). Data included demographics, medical history, blood tests (e.g., kidney function), MMSE, APOEε4, annual evaluations of cognition, and clinician-based dementia evaluation. The biomarkers' association with comorbidities, cognitive decline, and risk of dementia was examined within race. To examine racial differences, we repeated analyses using a subset Mahalanobis-balanced 1:1 on sex, age, education, Latino/Non-Latino, and clinical status (hypertension, diabetes, GFR, BMI, and heart disease).

Results

Biomarkers were measured in 431 Black and 583 White (respectively mean age of 77 and 80, 17% and 21% men), generating a balanced sample of 366:366. Biomarker's levels were similar between races. Within races, the associations of blood biomarkers with multiple comorbidities (especially kidney dysfunction and BMI) remained after controlling for demographics, APOE ε4, and dementia or death within 5 years. Men had lower GFAP levels than women (all p=<0.001). pTau217 was associated with decline in global cognition and all domains within races, and when comparing races, it was associated with a faster decline in global cognition and semantic memory in Black. The discrimination of dementia of pTau217 (AUC 3year, Black 0.81, CI=0.74, 0.89; AUC 3year, White 0.77, CI=0.71, 0.83) was good relative to age alone (AUC 3 year, Black 0.69, CI=0.58, 0.79; AUC 3 year, White 0.68, CI=0.62, 0.75), and MMSE (AUC 3 year, Black 0.81, CI=0.74, AUC 3 year, White 0.89; AUC 3 year, White 0.72, CI=0.65, 0.80). The discrimination of pTau217 did not improve by adding race or other biomarker information.

Discussion

pTau217 was highly associated with dementia risk and cognitive decline. The association of blood biomarkers with cognitive decline in Black and White participants was similar. Higher levels of pTau217 were, however, associated with semantic memory decline in Black adults. The combination of pTau217 with other biomarkers or MMSE did not improve dementia discrimination.

Exploring the power of MRI and clinical measures in predicting AD neuropathology

Predicting Alzheimer's disease (AD) pathology prior to clinical diagnosis is important for identifying individuals at high risk of developing AD dementia. However, there remains a gap in leveraging MRI and clinical data to predict AD pathology. This study examines a novel machine learning approach that integrates the combined vascular (white matter hyperintensities, WMHs) and structural brain changes (gray matter, GM) with clinical factors (cognitive scores) to predict post-mortem neuropathology. Participants from the Alzheimer's Disease Neuroimaging Initiative dataset (ADNI) and National Alzheimer's Coordinating Center (NACC) with both post-mortem neuropathology data and antemortem MRI and clinical data were included. Machine learning models were applied towards feature selection of the top seven MRI, clinical, and demographic data to identify the best performing set of variables that could predict postmortem neuropathology outcomes (i.e., neurofibrillary tangles, neuritic plaques, diffuse plaques, senile/amyloid plaques, and amyloid angiopathy). The best-performing neuropathology predictors from ADNI were then validated in NACC to compare results and ensure that the feature selection process did not lead to overfitting. In ADNI, the best-performing model included total and temporal lobe WMHs and achieved r = 0.87(RMSE = 0.62) during cross-validation for neuritic plaques. Overall, post-mortem neuropathology outcomes were predicted up to 14 years before death with high accuracies (~ 90%). Similar results were observed in the NACC dataset. These findings highlight that MRI features are critical to successfully predict AD-related pathology years in advance.

Associations between APOE-TOMM40 '523 haplotypes and limbic system white matter microstructure

INTRODUCTION

We assessed associations between apolipoprotein E Translocase of Outer Mitochondrial Membrane 40 (APOE-TOMM40)-'523 haplotypes and white matter microstructure (WMM) across limbic tracts important for memory and cognition in non-Hispanic Black and White individuals.

METHODS

Linear regression models, stratified by APOE and racialized groups, assessed associations between TOMM40-'523-S and limbic tract WMM free-water (FW) and free-water-corrected fractional anisotropy (FAFWcorr).

RESULTS

Black-ε4+-one-'523-S carriers had lower FW in the cingulum and inferior longitudinal fasciculus compared to Black-ε4+-no-'523-S carriers. Additionally, Black-ε4+-one-'523-S carriers had lower FW in the cingulum, uncinate, and fornix, and higher FAFWcorr in the uncinate compared to Black-ε4+-'523-S/S carriers. White-ε3/ε3-'523-S/S carriers had lower FAFWcorr in the cingulum and inferior temporal gyrus compared to White-ε3/ε3-no-'523-S carriers, and lower FAFWcorr in the cingulum compared to White-ε3/ε3-one-'523-S carriers.

DISCUSSION

This supports prior work that '523-S is associated with abnormal aging in White-ε3/ε3 carriers, but is potentially risk-mitigating in Black-ε4+ carriers, while suggesting a differential effect by racialized background of APOE on WMM.

Highlights

White matter microstructure (WMM) across limbic tracts important for cognition was measured by diffusion MRI.Black apolipoprotein E (APOE) ε4+ carriers with one copy of TOMM40-'523-S had normal aging WMM metrics across several tracts, including the cingulum bundle, uncinate fasciculus, fornix, and inferior longitudinal fasciculus.White APOE ε3/ε3 carriers with two copies of TOMM40-'523-S had abnormal aging WMM metrics in the cingulum bundle and inferior temporal gyrus.APOE associations with aging may differ in racialized groups due to TOMM40-'523-S copy number.

Grave injustice: the continuing use of unclaimed bodies in American medicine

Despite a growing sensitivity to the ethics of whole body donation in the field of clinical anatomy, the remains of unclaimed individuals continue to be used in healthcare teaching and research throughout the USA. I argue that this practice is unethical because of its disregard for autonomy and consent, its potential harm to various individuals and groups, considerations of justice and the threat that it poses to public trust in medical institutions. Additionally, I show how the best available defences of the use of unclaimed bodies fail to be ethically persuasive. I argue that whole body donation ethically requires either the prior consent of the deceased or the explicit permission of their next of kin. Finally, I offer practical suggestions for institutions transitioning away from the use of unclaimed bodies.

The Association of Dementia and Mild Cognitive Impairment With Outpatient Ambulatory Care Utilization in the Community

BACKGROUND

Ambulatory care is critical in delivering interventions for dementia and mild cognitive impairment (MCI), from basic services to novel therapeutics. Yet, little is known regarding how community-dwelling persons with dementia/MCI interact with clinicians in outpatient ambulatory settings. We assessed associations of dementia/MCI with outpatient ambulatory evaluation and management (E&M) visits.

METHODS

We included 2116 community-dwelling participants in Rush Alzheimer's Disease Center cohorts, with linked fee-for-service Medicare claims. Annually from 2011 to 2019, cohort neuropsychologic evaluations classified participants as dementia, MCI, or no cognitive impairment (NCI). Across groups, we compared annual probability of visiting providers and number of E&M visits, using repeated measures logistic or generalized Poisson mixed effects models.

RESULTS

Across 8672 person-years (PY) of follow-up, the mean age was 82 (SD 7.6) years; 77% of PYs were among females and 24% among Black participants. Controlling for demographics and comorbidity, the annual predicted probability of primary care visits was high in all groups (86%-92%). Although there were few visits with dementia-related specialists, we found a higher probability of these visits among those with dementia (15%) and MCI (17%) than NCI (12%; p = 0.009, dementia vs. NCI; p < 0.001, MCI vs. NCI). There were striking differences in visits to other medical specialties: the mean number of annual visits was 40% lower for those with dementia (p < 0.001) and 10% lower for MCI (p < 0.001) than NCI. Overall, dementia and MCI were associated with 19% (p < 0.001) and 4% (p = 0.005) fewer E&M visits, respectively, compared to NCI.

CONCLUSIONS

Older adults with dementia and MCI interact with primary care providers regularly and are more likely to use dementia-related specialists than those with NCI. Yet, we found lower utilization of other medical specialties, without compensatory increases in primary care, leading to fewer overall E&M visits, even in MCI. Together, the findings may suggest lost opportunities to address the scope of health issues in vulnerable groups.

Sleep health profiles across six population-based cohorts and recommendations for validating clustering models

OBJECTIVES

Model-based clustering is increasingly used to identify multidimensional sleep health profiles. However, generalizability is rarely assessed because of complexities of data sharing and harmonization. Our goal was to evaluate the generalizability of multidimensional sleep health profiles across older adult populations in Western countries and assess whether they predict depressive symptoms over time.

METHODS

We harmonized five self-reported sleep health indicators (satisfaction, alertness, timing, efficiency, and duration) across six population-based cohorts from the United States and Netherlands (N=614 - 3209 each) and performed identical latent class analysis in each cohort. Novel multivariable similarity metrics, patterns of sleep health and cluster sizes were used to match clusters and assess generalizability across cohorts. We compared cluster characteristics cross-sectionally and used linear mixed-effects modeling to relate sleep health clusters to depressive symptoms over time.

RESULTS

"Average sleep health" (moderate duration; high quality/efficiency; 42.7%-76.7% of sample) and "poor sleep health" (short duration; low quality/efficiency; high daytime sleepiness; 9.4%-20.4% of sample) clusters were generalizable across cohorts. In four cohorts "inefficient sleep" clusters were identified and in two cohorts "long, efficient sleep" clusters were identified. At 3years, those in the poor sleep cluster had depression symptoms that were 1.40-2.79 times greater than in the average sleep cluster, across all cohorts.

CONCLUSIONS

We identified two profiles - average sleep health and poor sleep health - that were generalizable across six samples of older adults and predicted depressive symptoms, underscoring the importance of the sleep health paradigm.

Permutations of cerebrovascular pathologies in older adults with and without diabetes

Permutations of cerebrovascular pathologies (CVP) in persons with diabetes mellitus (DM) have not been comprehensively investigated. Here, we examine diverse postmortem CVP outcomes, including permutations of single or mixed CVP, in 2163 older adults with or without DM who were followed in longitudinal studies of aging. Annual clinical evaluations included data to classify DM status by medical history (DM diagnosis), direct medication inspection (anti-diabetic therapy), and hemoglobin A1C level (≥6.5 %). Upon death, neuropathological examinations were performed and included evaluation for CVP (considering vessel pathologies and brain infarcts) and Alzheimer's disease neuropathologic change (AD-NC). Among all participants [mean age, 89.49 ± 6.89 years (SD)], single CVP were more common than mixed CVP. Logistic regression was used to analyze the association of DM with CVP permutations, controlling for age at death, sex, education, and AD-NC, and revealed increased odds of microinfarcts alone (odds ratio, 1.56 [95 %CI, 1.03-2.35]) and mixed microinfarcts and macroinfarcts (odds ratio, 1.90 [95 %CI, 1.16-3.13]). These associations remained after adjusting for demographic factors and cohort or vascular comorbidities including stroke, heart disease, hypertension, claudication, smoking, and systolic blood pressure. Furthermore, after controlling for demographic factors as well as AD-NC and APOE type, mixed microinfarcts and macroinfarcts were associated with approximate threefold increased risk of dementia (odds ratio, 2.95 [95 %CI, 1.13-7.70]) in participants with DM. Evidence suggests that older adults living with DM have higher odds of microinfarcts and mixed microinfarcts and macroinfarcts in the absence of intracranial vessel pathologies that cannot be explained by vascular comorbidities, and in this population mixed microinfarcts and macroinfarcts are associated with higher odds of dementia.

Developing and validating a prediction tool for cerebral amyloid angiopathy neuropathological severity

INTRODUCTION

Cerebral amyloid angiopathy (CAA) is a cerebrovascular condition, the severity of which can only be determined post mortem. Here, we developed machine learning models, the Florey CAA Score (FCAAS), to predict CAA severity (none/mild/moderate/severe).

METHODS

Building on an auto-score-ordinal algorithm, the FCAAS models were developed and validated using data collected by three cohort studies of aging and dementia. The developed FCAAS models were digitized as a web-based tool. A pilot trial was conducted using this web-based tool.

RESULTS

The FCAAS-4 achieved a mean area under the receiver operating characteristic curve (AUC-ROC) of 0.74 (95% confidence interval: 0.71-0.77) and a Harrell generalized c-index of 0.72 (0.70-0.75). Pilot trial results obtained a mean AUC-ROC of 0.82 (0.71-0.85) and Harrell generalized c-index 0.79 (0.73-0.82).

DISCUSSION

The FCAAS models demonstrate a promising performance in predicting CAA severity. This framework holds the potential for predicting development of amyloid-related imaging abnormalities (ARIAs), given the CAA-ARIAs link.

HIGHLIGHTS

The severity of cerebral amyloid angiopathy (CAA) can only be determined post mortem. A web tool, the Florey CAA Score (FCAAS), was developed to predict CAA severity. The FCAAS holds the potential to be used for CAA risk stratification in clinics. CAA is linked to increased risk of amyloid-related imaging abnormalities (ARIAs). The framework used by FCAAS can possibly be adapted to predict ARIAs risk.

Exploring epidemiological risk factors for cerebral amyloid angiopathy: Considerations for monoclonal antibody therapy in people with Alzheimer's disease

INTRODUCTION

Cerebral amyloid angiopathy (CAA) increases the risk of amyloid-related imaging abnormalities in Alzheimer's disease (AD) patients receiving anti-amyloid-beta therapies, emphasizing the need to identify its risk factors.

METHODS

Data were collected from three cohort studies, and a machine learning model was developed to predict CAA occurrence using the selected risk factors.

RESULTS

The AD neuropathologic changes (ADNC)-CAA association was significantly positive in the cross-sectional analysis. When stratified by selected risk factors, this association was generally stronger among females, smokers, people with a history of stroke/memory complaints, apolipoprotein E (APOE)-ε4 carriers, and those without diabetes/heart conditions. In the longitudinal analysis of the association between potential risk factors and CAA, a higher risk of CAA was observed among males, older individuals, smokers, people with diabetes/heart conditions, lower Mini-Mental State Examination (MMSE) scores, and APOE-ε4 carriers compared to their respective reference groups.

DISCUSSION

Our study identified risk factors for cerebral amyloid angiopathy, informing potential prevention strategies.

HIGHLIGHTS

ADNC were significantly positively associated with the risk of CAA. The ADNC-CAA association was generally stronger among females, smokers, people with a history of stroke/memory complaints, APOE-ε4 carriers, and those without diabetes or heart conditions. Longitudinally, higher CAA risk was observed among males, older individuals, smokers, people with diabetes/heart conditions/lower MMSE scores, and APOE-ε4 carriers compared to their reference groups.

Social factors associated with everyday functioning in older Black adults

OBJECTIVE

Independence in everyday functioning has been associated with successful aging and declines in functioning may be indicative of pathological cognitive decline. Social determinants of health, like economic status and access to health care, a]lso play a role in everyday functioning. Understanding these factors are of particular importance for older Black adults who have had long-standing disparate access to care, education, and treatments. The current study aimed to evaluate social determinants of health, more specifically social engagement, as moderators of the association between cognition and everyday functioning.

METHOD

A sample of 930 older Black adults from Rush University: The Memory and Aging Project, African American Clinical Core, and Minority Adult Research Study were used. Participants completed a battery of neuropsychological testing as well as questionnaires about their everyday functioning and social behaviors. Hierarchical linear regressions were utilized to determine to what extent social factors moderated the relationship between cognition and everyday functioning.

RESULTS

Late life social activity reduced the effect of global cognition on everyday functioning and was independently associated with everyday functioning. Social network size was associated with increased impairment.

CONCLUSION

Results from the current study provide novel information regarding the role of social interaction on cognition in an older Black adult sample. Future interventions may benefit from an emphasis on increasing social engagement.

Association of late-life variability in hemoglobin A1C with postmortem neuropathologies

INTRODUCTION

To study the relationship of late-life hemoglobin A1C (A1C) with postmortem neuropathology in older adults with and without diabetes mellitus (DM).

METHODS

A total of 990 participants from five cohort studies of aging and dementia with at least two annually-collected A1C measures, who had autopsy. Neuropathologic evaluations documented cerebrovascular disease, Alzheimer's disease (AD), and other pathologies. To evaluate the association of A1C mean and variability (standard deviation [SD]) with neuropathology, we used a series of adjusted regression models.

RESULTS

Participants (mean age at death = 90.8 years; education = 15.8 years; 76% women) had six A1C measurements on average. Mean A1C was associated with greater odds of macroinfarcts (estimate = 0.14; p = 0.04) and subcortical infarcts (estimate = 0.16; p = 0.02). A1C variability was not associated with cerebrovascular pathology. A1C mean and variability were inversely associated with AD pathology.

DISCUSSION

The A1C average over time was associated with infarcts, and the A1C average and variability were inversely associated with AD pathology. Future studies should explore the underlying mechanisms linking A1C to dementia-related neuropathologies.

HIGHLIGHTS

Hemoglobin A1C (A1C), a measure of peripheral insulin resistance, is used to assess glycemic control. Higher A1C mean was associated with greater odds of macroscopic subcortical infarcts. A1C variability was not associated with cerebrovascular pathology. Both A1C mean and variability had inverse associations with AD pathology. None of the associations varied by diabetes mellitus status.

Hippocampal neuronal loss and cognitive decline in LATE-NC and ADNC among community-dwelling older persons

INTRODUCTION

This study investigates the inter-related roles of hippocampal neuronal loss (HNL), limbic-predominant age-related TAR-DNA binding protein of 43 kDa (TDP-43) encephalopathy neuropathologic changes (LATE-NC), and Alzheimer's disease neuropathologic changes (ADNC) on cognitive decline.

METHODS

Participants underwent annual cognitive testing and autopsy. HNL, ADNC, LATE-NC, and other age-related pathologies were evaluated. Regression and mixed-effects models examined the association of HNL with ADNC and LATE-NC, and separately with cognitive decline. Path analyses examined the extent to which associations of LATE-NC and ADNC with cognitive decline were attributable to HNL.

RESULTS

LATE-NC was associated with more severe HNL, but ADNC was associated only after excluding subjects with hippocampal sclerosis (HS). HNL was associated with faster decline in global cognition and episodic, semantic, and working memory. In path analyses, about 61% of the association of LATE-NC with cognitive decline was attributable to HNL, whereas for ADNC it was mostly independent of HNL.

DISCUSSION

HNL has an independent contribution to cognitive decline and acts as a major step in LATE-NC-related cognitive decline.

HIGHLIGHTS

Hippocampal neuronal loss (HNL) is associated with cognitive decline. HNL is a prominent feature of limbic-predominant age-related TDP-43 encephalopathy neuropathologic changes (LATE-NC) and less so with Alzheimer's disease neuropathologic changes (ADNC). HNL acts as a major pathway in cognitive decline for LATE-NC. Differential mechanisms in hippocampal degeneration are associated with LATE-NC versus ADNC.

Sex differences in the association between age-related decline in blood pressure and decline in cognition: A prospective cohort study

Background

Both high and declining blood pressure (BP) are associated with cognitive decline risk in older adults. In late-life, women have higher rates of hypertension, experience faster cognitive decline, and represent two-thirds of individuals with Alzheimer's disease dementia. However, sex differences in the association between BP decline and cognitive decline are unknown.

Methods

Data were analyzed from 4719 older adults without known baseline dementia (mean age = 76.7 [SD = 7.7] years; 74% women) enrolled in one of five US-based prospective community-based cohort studies, followed annually for up to 31 years (mean = 8.7 [SD = 5.7] years). A 19-test cognitive battery, yielding composite global and five domain-specific scores, and BP were assessed annually. Bivariate mixed-effects models simultaneously estimated change in BP and cognition, for the total group and by sex.

Findings

Systolic BP, diastolic BP, and cognition all declined over time (ps <0.01). Bivariate mixed-effect models revealed a sex difference in the correlation of decline in systolic BP and decline in global cognition (women: r = 0.26, 95%CI: 0.17 - 0.37; men: r = 0.01, 95%CI: -0.13 - 0.11), such that women exhibited a stronger correlation than men. Decline in systolic BP was related to decline in global and all five cognitive domains in women but none in men, with another sex difference identified in the working memory domain. An increase of diastolic BP was related to decline in working memory in men, and no other associations with diastolic BP were significant for either sex.

Interpretation

Systolic BP decline in late-life is related to decline in global and domain-specific cognition in women but not men, with sex differences in global cognition and the working memory domain. These findings suggest that in older women, declining systolic BP - a routinely-used clinical measure - may be an important marker of concurrent cognitive decline.

Evaluating the association of APOE genotype and cognitive resilience in SuperAgers

Importance

"SuperAgers" are oldest-old adults (ages 80+) whose memory performance resembles that of adults in their 50s to mid-60s. Factors underlying their exemplary memory are underexplored in large, racially diverse cohorts.

Objective

To determine the frequency of APOE genotypes in non-Hispanic Black and non-Hispanic White SuperAgers compared to middle-aged (ages 50-64), old (ages 65-79), and oldest-old (ages 80+) controls and Alzheimer's disease (AD) dementia cases.

Design

This multicohort study selected data from eight longitudinal cohort studies of normal aging and AD.

Setting

Variable recruitment criteria and follow-up intervals, including both population-based and clinical-based samples.

Participants

Inclusion in our analyses required APOE genotype, that participants be age 50+, and are identified as either non-Hispanic Black or non-Hispanic White. In total, 18,080 participants were included in the present study with a total of 78,549 datapoints.

Main Outcomes and Measures

Harmonized, longitudinal memory, executive function, and language scores were obtained from the Alzheimer's Disease Sequencing Project Phenotype Harmonization Consortium (ADSP-PHC). SuperAgers, controls, and AD dementia cases were identified by cognitive scores using a residual approach and clinical diagnoses across multiple timepoints when available. SuperAgers were compared to AD dementia cases and cognitively normal controls using age-defined bins (middle-aged, old, oldest-old).

Results

Across racialized groups, SuperAgers had significantly higher proportions of APOE-ε2 alleles and lower proportions of APOE-ε4 alleles compared to cases. Similar differences were observed between SuperAgers and middle-aged and old controls. Non-Hispanic White SuperAgers had significantly lower proportions of APOE-ε4 alleles and significantly higher proportions of APOE-ε2 alleles compared to all cases and controls, including oldest-old controls. In contrast, non-Hispanic Black SuperAgers had significantly lower proportions of APOE-ε4 alleles compared to cases and younger controls, and significantly higher proportions of APOE-ε2 alleles compared only to cases.

Conclusions and Relevance

In the largest study to date, we demonstrated strong evidence that the frequency of APOE-ε4 and -ε2 alleles differ between non-Hispanic White SuperAgers and AD dementia cases and cognitively normal controls. Differences in the role of APOE in SuperAging by race underlines distinctions in mechanisms conferring resilience across race groups given likely differences in genetic ancestry.

The Dynamics of Cognitive Decline towards Alzheimer's Disease Progression: Results from ADSP-PHC's Harmonized Cognitive Composites

INTRODUCTION

Accurately assessing temporal order of cognitive decline across multiple domains is critical in Alzheimer's disease (AD). Existing literature presented controversial conclusions likely due to the use of a single cohort and different analytical strategies.

METHODS

Harmonized composite cognitive measures in memory, language and executive functions from 13 cohorts in the ADSP-PHC data are used. A novel double anchoring events-based sigmoidal mixed model was developed using time to the incident of AD diagnosis as the time scale.

RESULTS

Decline in memory occurred before decline in language which was followed by the decline in executive function. Throughout the entire AD continuum, APOE-ε4 non-carriers and non-Hispanic Whites showed better memory performance, respectively, in all three cognitive domains.

DISCUSSION

Using harmonized data across multiple cohorts is the key to accurately characterizing the temporal order of AD biomarkers. Time to incident AD diagnosis should be used as the time scale for reproducibility purposes.

Review of Associations of Diabetes and Insulin Resistance With Brain Health in Three Harmonised Cohort Studies of Ageing and Dementia

Diabetes increases the risk of dementia, and insulin resistance (IR) has emerged as a potential unifying feature. Here, we review published findings over the past 2 decades on the relation of diabetes and IR to brain health, including those related to cognition and neuropathology, in the Religious Orders Study, the Rush Memory and Aging Project, and the Minority Aging Research Study (ROS/MAP/MARS), three harmonised cohort studies of ageing and dementia at the Rush Alzheimer's Disease Center (RADC). A wide range of participant data, including information on medical conditions such as diabetes and neuropsychological tests, as well as other clinical and laboratory-based data collected annually. Neuropathology data are collected in participants who agree to autopsy at death. Recent studies have measured additional peripheral and brain IR data, including multi-omics. This review summarises findings from the RADC cohort studies that investigate the relation of diabetes and IR in older adults to cognition, neuropathology, omics in dementia, and other brain health measures. Examining the risk of clinically diagnosed dementia in older adults, our study found a 65% increased risk of Alzheimer's disease (AD) dementia in individuals with diabetes compared with those without. Regarding cognitive function, we have consistently observed associations of diabetes, as well as both peripheral and brain IR, with worse and declining performance in global cognition and specific cognitive domains, particularly semantic memory and perceptual speed. Studies utilising neuropathological data showed associations of diabetes and peripheral IR with brain infarcts, while brain IR measures, notably alpha serine/threonine-protein kinase1 (AKT1), were associated with both brain infarcts and AD pathology. Multi-omics studies suggested shared causal genes and pathways between diabetes and dementia. Recent epigenetic studies have revealed associations between IR and AD risk, along with distinct 5-hydroxymethylcytosine signatures in diabetes-associated AD. Furthermore, our studies have utilised other available data to investigate the impact of diabetes on neurological outcomes other than cognition and reported worsening of parkinsonian-like signs in diabetes. Recent studies have also explored risk factors for diabetes and have reported associations between lower literacy and decision-making abilities with elevated haemoglobin A1C levels, a peripheral IR measure. Overall, our findings, as summarised in this review, illustrate a range of mechanistic and other insights into the complex relationship of diabetes and IR with brain health. These findings may have important implications for future research on the ageing brain, including the prevention of cognitive decline and dementia in persons at risk for or with diabetes.

Sex and APOE ε4 allele differences in longitudinal white matter microstructure in multiple cohorts of aging and Alzheimer's disease

INTRODUCTION

The effects of sex and apolipoprotein E (APOE)-Alzheimer's disease (AD) risk factors-on white matter microstructure are not well characterized.

METHODS

Diffusion magnetic resonance imaging data from nine well-established longitudinal cohorts of aging were free water (FW)-corrected and harmonized. This dataset included 4741 participants (age = 73.06 ± 9.75) with 9671 imaging sessions over time. FW and FW-corrected fractional anisotropy (FAFWcorr) were used to assess differences in white matter microstructure by sex and APOE ε4 carrier status.

RESULTS

Sex differences in FAFWcorr in projection tracts and APOE ε4 differences in FW limbic and occipital transcallosal tracts were most pronounced.

DISCUSSION

There are prominent differences in white matter microstructure by sex and APOE ε4 carrier status. This work adds to our understanding of disparities in AD. Additional work to understand the etiology of these differences is warranted.

HIGHLIGHTS

Sex and apolipoprotein E (APOE) ε4 carrier status relate to white matter microstructural integrity. Females generally have lower free water-corrected fractional anisotropy compared to males. APOE ε4 carriers tended to have higher free water than non-carriers.

The Effects of APOE Alleles, Cognitive Activities, and Social Activities on Cognitive Decline in African Americans

OBJECTIVES

Older African Americans are among the fastest-growing populations, yet are underrepresented in studies examining risk factors related to decline. The present study examines whether biological factors (apolipoprotein [APOE] alleles) interact with behavioral factors including cognitive activities (e.g., reading, playing games) and social activities (e.g., participating in social groups) to predict cognitive decline in African Americans.

METHODS

In total, 734 African American adults from the Minority Aging Research Study, aged 65 and older (with no known dementia at the time of enrollment), underwent annual cognitive testing for up to 10 years. At baseline, APOE status was determined and participants reported their frequency of participation in social and cognitive activities. Structural equation modeling was used to examine the effects of APOE, cognitive activities, and social activities on cognitive decline, and their interaction effects over a 10-year period.

RESULTS

The number of APOE alleles had an effect on cognitive decline, such that a greater number of APOE4 alleles was associated with greater cognitive decline, whereas a greater number of APOE2 alleles was associated with less cognitive decline. Cognitive and social activities did not interact with APOE count to predict cognitive decline; however, APOE4 and social activities had additive, independent effects on cognitive decline.

DISCUSSION

Results replicate prior findings linking APOE4 to cognitive decline and highlight the importance of APOE2 and social activities in delaying cognitive decline in African Americans.

Biological validation of peak-width of skeletonized mean diffusivity as a VCID biomarker: The MarkVCID Consortium

BACKGROUND

Peak-width of skeletonized mean diffusivity (PSMD), a neuroimaging marker of cerebral small vessel disease (SVD), has shown excellent instrumental properties. Here, we extend our work to perform a biological validation of PSMD.

METHODS

We included 396 participants from the Biomarkers for Vascular Contributions to Cognitive Impairment and Dementia (MarkVCID-1) Consortium and three replication samples (Cohorts for Heart and Aging Research in Genomic Epidemiology = 6172, Rush University Medical Center = 287, University of California Davis Alzheimer's Disease Research Center = 567). PSMD was derived from diffusion tensor imaging using an automated algorithm. We related PSMD to a composite measure of general cognitive function using linear regression models adjusting for confounders.

RESULTS

Higher PSMD was associated with lower general cognition in MarkVCID-1 independent of age, sex, education, and intracranial volume (Beta [95% confidence interval], -0.8 [-1.2, -0.4], P < 0.001). These findings were replicated in independent samples. Furthermore, PSMD explained cognitive status above and beyond white matter hyperintensities.

DISCUSSION

Our biological validation work supports the pursuit of larger clinical validation studies evaluating PSMD as a susceptibility/risk biomarker of small vessel disease contributing to cognitive impairment and dementia.

HIGHLIGHTS

Peak-width of skeletonized mean diffusivity (PSMD) is a novel small vessel disease neuroimaging biomarker. A prior instrumental validation study demonstrated that PSMD is a robust biomarker. This biological validation study shows that high PSMD relates to worse cognition. PSMD explains cognitive function above and beyond white matter hyperintensities. Future clinical validation will assess PSMD as a vascular contribution to cognitive impairment and dementia biomarker in clinical trials.

Epistatic effects of IGHG and FCGRIIB genes on the development of Alzheimer's disease in African Americans

Genome-wide association studies (GWAS) of Alzheimer's disease (AD) have identified a large number of susceptibility genes, but most of AD heritability remains unexplained, implying the existence of additional genes. Furthermore, the majority of the GWAS have been conducted in people of European descent, and the genes important for AD susceptibility in people of African descent have been underexplored. In this hypothesis-generating prospective cohort study, we genotyped 191 African Americans (AAs) from three longitudinal cohorts on aging for the IgG3 allotype GM6, which is expressed exclusively in people of African descent, and assessed its interaction with IGHG, FCGRIIB, and HLA-DRB1 genes. Cox proportional hazards modeling showed that GM6 by itself was not significantly associated with AD development. However, there was evidence of epistatic interaction: The risk of developing AD associated with GM6 positivity was significantly different (p = 0.0098) in non-GM17/GM17 participants compared with GM 17/GM17 participants. Specifically, in non-GM17/GM17 participants, the risk of AD was over fourfold higher in GM6-positive participants compared with GM 6-negative participants (HR = 4.63). Similarly, risk of developing AD associated with GM6 positivity was marginally different in non-FCGRIIB TT participants compared with FCGRIIB TT participants. In non-FCGRIIB TT participants, the risk of developing AD was over twofold higher in GM6-positive participants compared with GM6-negative participants (HR = 2.44). This is the first report suggesting that immunoglobulin GM allotypes might play a role in AD etiology among AAs; however, since this was largely a hypothesis-generating study, replication in larger cohorts would be required to confirm this finding.

Grey matter ageing-related tau astrogliopathy: associations with brain pathologies and cognitive decline

Grey matter ageing-related tau astrogliopathy (ARTAG) pathology is common in aged brains and detected in multiple brain regions. However, the associations of grey matter ARTAG with Alzheimer's disease and other common age-related proteinopathies, in addition to clinical phenotypes, including Alzheimer's dementia and cognitive decline, remain unclear. We examined 442 decedents (mean age at death = 90 years, males = 32%) from three longitudinal community-based clinical-pathological studies. Using AT8 immunohistochemistry, grey matter ARTAG pathology was counted in the superior frontal region, anterior temporal tip and amygdala and summarized as a severity score ranging from zero (none) to six (severe). Alzheimer's disease and other common age-related neuropathologies were also evaluated. The diagnosis of Alzheimer's dementia was based on clinical evaluations; annual tests of cognitive performance were summarized as global cognition and five cognitive domains. Multivariable logistic regression tested the associations of grey matter ARTAG pathology with an array of age-related neuropathologies. To evaluate associations of grey matter ARTAG pathology with Alzheimer's dementia and cognitive decline, we used logistic regression and linear mixed-effect models. Grey matter ARTAG pathology was seen in 324 (73%) participants, of which 303 (68%) participants had ARTAG in the amygdala, 246 (56%) in the anterior temporal tip and 137 (31%) in the superior frontal region. Grey matter ARTAG pathology from each of the three regions was associated with a pathological diagnosis of Alzheimer's disease and limbic-predominant age-related TAR DNA-binding protein 43 encephalopathy-neuropathological change but not with vascular pathology. In fully adjusted models that controlled for demographics, Alzheimer's disease and common age-related pathologies, an increase in severity of grey matter ARTAG pathology in the superior frontal cortex, but not in the amygdala or the anterior temporal tip, was associated with higher odds of Alzheimer's dementia and faster decline in global cognition, episodic memory and semantic memory. These results provide compelling evidence that grey matter ARTAG, specifically in the superior frontal cortex, contributes to Alzheimer's dementia and cognitive decline in old age.

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 Black Americans (BA) and Latin Americans (LA), who are disproportionately affected by AD.

METHODS

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

RESULTS

We generated multi-omics data and curated and harmonized phenotypic data from BA (n = 306), LA (n = 326), or BA 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 BA 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

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

HIGHLIGHTS

Accelerating Medicines Partnership in Alzheimer's Disease Diversity Initiative led brain tissue profiling in multi-ethnic populations. Brain multi-omics data is generated from Black American, Latin American, and non-Hispanic White donors. RNA, whole genome sequencing and tandem mass tag proteomicsis completed and shared. Multiple brain regions including caudate, temporal and dorsolateral prefrontal cortex were profiled.

Loneliness, cerebrovascular and Alzheimer's disease pathology, and cognition

INTRODUCTION

Loneliness has a rising public health impact, but research involving neuropathology and representative cohorts has been limited.

METHODS

Inverse odds of selection weights were generalized from the autopsy sample of Rush Alzheimer's Disease Center cohorts (N = 680; 89 ± 9 years old; 25% dementia) to the US-representative Health and Retirement Study (N = 8469; 76 ± 7 years old; 5% dementia) to extend external validity. Regressions tested cross-sectional associations between loneliness and (1) Alzheimer's disease (AD) and cerebrovascular pathology; (2) five cognitive domains; and (3) relationships between pathology and cognition, adjusting for depression.

RESULTS

In weighted models, greater loneliness was associated with microinfarcts, lower episodic and working memory in the absence of AD pathology, lower working memory in the absence of infarcts, a stronger association of infarcts with lower episodic memory, and a stronger association of microinfarcts with lower working and semantic memory.

DISCUSSION

Loneliness may relate to AD through multiple pathways involving cerebrovascular pathology and cognitive reserve.

HIGHLIGHTS

Loneliness was associated with worse cognition in five domains. Loneliness was associated with the presence of microinfarcts. Loneliness moderated cognition-neuropathology associations. Transportability methods can provide insight into selection bias.

Development and validation of the Florey Dementia Risk Score web-based tool to screen for Alzheimer's disease in primary care

Background

It is estimated that ∼60% of people with Alzheimer's disease (AD) are undetected or undiagnosed, with higher rates of underdiagnosis in low-to middle-income areas with limited medical resources. To promote health equity, we have developed a web-based tool that utilizes easy-to-collect clinical data to enhance AD detection rate in primary care settings.

Methods

This study was leveraged on the data collected from participants of the Australian Imaging, Biomarker & Lifestyle (AIBL) study and the Religious Orders Study and Memory and Aging Project (ROSMAP). The study included three phases: (1) constructing and evaluating a model on retrospective cohort data (1407 AIBL participants), (2) performing simulated trials to assess model accuracy (30 AIBL participants) and missing data tolerability (30 AIBL participants), and (3) external evaluation using a non-Australian dataset (500 ROSMAP participants). The auto-score machine learning algorithm was employed to develop the Florey Dementia Risk Score (FDRS). All the simulated trials and evaluation were performed using a web-based FDRS tool.

Findings

FDRS achieved an area under the curve (AUC) of approximately 0.82 [95% CI, 0.75-0.88], with a sensitivity of 0.74 [0.60-0.86] and a specificity of 0.73 [0.70-0.79]. The accuracy of the simulated pilot trial for 30 AIBL participants with complete record was 87% (26/30 correct), while it only slightly decreased (80.0-83.3%, depending on imputation methods) for another 30 AIBL participants with one or two missing data. FDRS achieved an AUC of 0.82 [0.77-0.86] of 500 ROSMAP participants.

Interpretation

The FDRS tool offers a potential low-cost solution to AD screening in primary care. The present study warrants future trials of FDRS for optimization and to confirm its generalizability across a more diverse population, especially people in low-income countries.

Funding

National Health and Medical Research Council, Australia (GNT2007912) and Alzheimer's Association, USA (23AARF-1020292).

Pioneering a multi-phase framework to harmonize self-reported sleep data across cohorts

STUDY OBJECTIVES

Harmonizing and aggregating data across studies enables pooled analyses that support external validation and enhance replicability and generalizability. However, the multidimensional nature of sleep poses challenges for data harmonization and aggregation. Here we describe and implement our process for harmonizing self-reported sleep data.

METHODS

We established a multi-phase framework to harmonize self-reported sleep data: (1) compile items, (2) group items into domains, (3) harmonize items, and (4) evaluate harmonizability. We applied this process to produce a pooled multi-cohort sample of five US cohorts plus a separate yet fully harmonized sample from Rotterdam, Netherlands. Sleep and sociodemographic data are described and compared to demonstrate the utility of harmonization and aggregation.

RESULTS

We collected 190 unique self-reported sleep items and grouped them into 15 conceptual domains. Using these domains as guiderails, we developed 14 harmonized items measuring aspects of satisfaction, alertness/sleepiness, timing, efficiency, duration, insomnia, and sleep apnea. External raters determined that 13 of these 14 items had moderate-to-high harmonizability. Alertness/Sleepiness items had lower harmonizability, while continuous, quantitative items (e.g. timing, total sleep time, and efficiency) had higher harmonizability. Descriptive statistics identified features that are more consistent (e.g. wake-up time and duration) and more heterogeneous (e.g. time in bed and bedtime) across samples.

CONCLUSIONS

Our process can guide researchers and cohort stewards toward effective sleep harmonization and provide a foundation for further methodological development in this expanding field. Broader national and international initiatives promoting common data elements across cohorts are needed to enhance future harmonization and aggregation efforts.

Beyond Hypertension: Examining Variable Blood Pressure's Role in Cognition and Brain Structure

OBJECTIVES

Hypertension or high blood pressure (BP) is one of the 12 modifiable risk factors that contribute to 40% of dementia cases that could be delayed or prevented. Although hypertension is associated with cognitive decline and structural brain changes, less is known about the long-term association between variable BP and cognitive/brain changes. This study examined the relationship between variable BP and longitudinal cognitive, white matter hyperintensity (WMH), gray matter (GM), and white matter (WM) volume change over time and postmortem neuropathology.

METHODS

A total of 4,606 participants (32,776 follow-ups) from RADC Research Resource Sharing Hub (RUSH) and 2,114 participants (9,827 follow-ups) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) were included. Participants were divided into 1 of 3 groups: normal, high, or variable BP. Linear-mixed models investigated the relationship between BP and cognition, brain structure, and neuropathology.

RESULTS

Older adults with variable BP exhibited the highest rate of cognitive decline followed by high and then normal BP. Increased GM volume loss and WMH burden were also observed in variable compared to high and normal BP. In postmortem neuropathology, both variable and high BP had increased rates compared to normal BP. Results were consistent across the RUSH and ADNI participants, supporting the generalizability of the findings.

DISCUSSION

Damages potentially associated with variable BP may reduce resilience to future dementia-related pathology and increased the risk of dementia more than that caused by high BP. Improved treatment and management of variable BP may help reduce cognitive decline in the older adult population.

Correlates of missed or late versus timely diagnosis of dementia in healthcare settings

INTRODUCTION

There is limited evidence about factors related to the timeliness of dementia diagnosis in healthcare settings.

METHODS

In five prospective cohorts at Rush Alzheimer's Disease Center, we identified participants with incident dementia based on annual assessments and examined the timing of healthcare diagnoses in Medicare claims. We assessed sociodemographic, health, and psychosocial correlates of timely diagnosis.

RESULTS

Of 710 participants, 385 (or 54%) received a timely claims diagnosis within 3 years prior to or 1 year following dementia onset. In logistic regressions accounting for demographics, we found Black participants (odds ratio [OR] = 2.15, 95% confidence interval [CI]: 1.21 to 3.82) and those with better cognition at dementia onset (OR = 1.48, 95% CI: 1.10 to 1.98) were at higher odds of experiencing a diagnostic delay, whereas participants with higher income (OR = 0.89, 95% CI: 0.81 to 0.97) and more comorbidities (OR = 0.94, 95% CI: 0.89 to 0.98) had lower odds.

DISCUSSION

We identified characteristics of individuals who may miss the optimal window for dementia treatment and support.

HIGHLIGHTS

We compared the timing of healthcare diagnosis relative to the timing of incident dementia based on rigorous annual evaluation. Older Black adults with lower income, higher cognitive function, and fewer comorbidities were less likely to be diagnosed in a timely manner by the healthcare system.

Limbic-predominant age-related TDP-43 encephalopathy neuropathological change (LATE-NC) is associated with abnormalities in white matter structural integrity and connectivity: An ex-vivo diffusion MRI and pathology investigation

Limbic predominant age-related TDP-43 encephalopathy neuropathological change (LATE-NC) is common in older adults and is associated with neurodegeneration, cognitive decline and dementia. In this MRI and pathology investigation we tested the hypothesis that LATE-NC is associated with abnormalities in white matter structural integrity and connectivity of a network of brain regions typically harboring TDP-43 inclusions in LATE, referred to here as the "LATE-NC network". Ex-vivo diffusion MRI and detailed neuropathological data were collected on 184 community-based older adults. Linear regression revealed an independent association of higher LATE-NC stage with lower diffusion anisotropy in a set of white matter connections forming a pattern of connectivity that is consistent with the stereotypical spread of this pathology in the brain. Graph theory analysis revealed an association of higher LATE-NC stage with weaker integration and segregation in the LATE-NC network. Abnormalities were significant in stage 3, suggesting that they are detectable in later stages of the disease. Finally, LATE-NC network abnormalities were associated with faster cognitive decline, specifically in episodic and semantic memory.

Cerebral arteriolosclerosis, lacunar infarcts, and cognition in older Black adults

INTRODUCTION

Older Black adults are at risk of cerebral small vessel disease (CSVD), which contributes to dementia risk. Two subtypes of CSVD, arteriolosclerosis and ischemic lacunar infarcts, have been independently linked to lower cognition and higher dementia risk, but their combined effects on cognition in older Black adults are unclear.

METHODS

Mixed models were used to examine the associations of in vivo measures of arteriolosclerosis (ARTS) and ischemic lacunar infarcts to cognitive level and change in 370 older Black adults without dementia.  RESULTS: Modeled together, higher ARTS load accounted for lower levels of global cognition, episodic memory, semantic memory, and perceptual speed, whereas higher infarct load accounted for lower levels of working memory. There were no associations with rate of cognitive change.

DISCUSSION

Both arteriolosclerosis and ischemic infarcts impact the cognitive health of older Black adults, but arteriolosclerosis affects cognition more broadly and offers promise as an in vivo biomarker of dementia risk.

HIGHLIGHTS

Older Black adults are at risk of cerebral small vessel disease (CSVD) and dementia. Examined magnetic resonance imaging-derived measure of arteriolosclerosis (ARTS), infarcts, and cognition. ARTS load was widely associated with lower cognition after adjusting for infarct load. Infarct load was specifically associated with lower complex attention. More within-Black in vivo studies of CSVD subtypes and cognition are needed.

Quantitative assessment of enlarged perivascular spaces via deep-learning in community-based older adults reveals independent associations with vascular neuropathologies, vascular risk factors and cognition

Enlarged perivascular spaces (EPVS) are common in older adults, but their neuropathologic correlates are unclear mainly because most work to date has relied on visual rating scales and/or clinical cohorts. The present study first developed a deep-learning model for automatic segmentation, localization and quantification of EPVS in ex vivo brain MRI, and then used this model to investigate the neuropathologic, clinical and cognitive correlates of EPVS in 817 community-based older adults that underwent autopsy. The new method exhibited high sensitivity in detecting EPVS as small as 3 mm3, good segmentation accuracy and consistency. Most EPVS were located in the frontal lobe, but the highest density was observed in the basal ganglia. EPVS in the cerebrum and specifically in the frontal lobe were associated with infarcts independent of other neuropathologies, while temporal and occipital EPVS were associated with cerebral amyloid angiopathy. EPVS in most brain lobes were also associated with diabetes mellitus independently of neuropathologies, while basal ganglia EPVS were independently associated with hypertension, supporting the notion of independent pathways from diabetes and hypertension to EPVS. Finally, EPVS were associated with lower cognitive performance independently of neuropathologies and clinical variables, suggesting that EPVS represent additional abnormalities contributing to lower cognition.

Depression, loneliness, and lower social activity as partial mediators of the association between visual impairment and cognitive decline

OBJECTIVES

Sensory impairment is a hypothesized risk factor for cognitive decline; however, the psychosocial pathways are not well understood. We evaluated whether the association between visual impairment (VI) and cognitive decline was partially mediated via depressive symptoms, loneliness, or social activity.

METHODS

We used data from 2601 older adults enrolled in the Memory and Aging Project in 1997 and the Minority Aging Research Study in 2004 with neuropsychological tests across five domains measured annually for up to 16 years. VI was assessed with the Rosenbaum Pocket Vision Screener. Depressive symptoms, loneliness, and social activity were self-reported using validated scales. We used structural equation models to estimate the associations of VI with baseline and change in cognitive function, directly and indirectly through each mediator (depressive symptoms, loneliness, and social activity). We evaluated mediation via "psychological distress" using a latent variable combining depressive symptoms and loneliness.

RESULTS

The association between VI and global cognitive decline was mediated via lower social activity (indirect effect) [95% confidence interval (CI)] of linear slope: -0.025 (-0.048, -0.011), via loneliness (-0.011 [95% CI: -0.028, -0.002]), and via psychological distress (-0.017 [95% CI: -0.042, -0.003]). We did not find sufficient evidence for mediation via depressive symptoms alone.

CONCLUSIONS

The harmful effect of VI on cognitive decline may be partially mediated through loneliness and lower social activity.

Racial differences in the effect of verbal and nonverbal memory on concrete planning for future care needs among older adults: a multi-group structural equation modeling approach

Concrete planning for future care needs may positively impact older adults' subsequent mental health and quality of life. However, the cognitive factors that facilitate concrete planning among Black and White older adults are still poorly understood. We investigated whether there are significant differences between Black (n = 159) and White (n = 262) older adults in concrete planning and explored racial differences in the relationship between verbal and nonverbal episodic memory and concrete planning. Results revealed that Blacks showed lower engagement in concrete planning and lower scores than Whites on each verbal and nonverbal memory task. For Blacks, but not Whites, verbal memory and nonverbal memory performance predicted concrete planning with higher nonverbal memory relating to less concrete planning and higher verbal memory associated with more concrete planning. Our findings suggest racial differences exist in how episodic verbal and nonverbal memory affect concrete planning, a crucial factor for older adults' preparation for future care.

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.

Meeting report of the fifth annual workshop on Principles and Techniques for Improving Preclinical to Clinical Translation in Alzheimer's Disease Research

The fifth annual workshop on Principles and Techniques for Improving Preclinical Translation of Alzheimer's Disease Research was held in May 2023 at The Jackson Laboratory in Bar Harbor, Maine, USA. The workshop was established in 2018 to address training gaps in preclinical translational studies for Alzheimer's disease (AD). In addition to providing fundamental knowledge and hands-on skills essential for executing rigorous in vivo studies that are designed to facilitate translation, each year the workshop aims to provide insight on state-of-the-field technological advances and new resources including novel animal models, publicly available datasets, novel biomarkers, and new medical imaging tracers. This innovative and comprehensive workshop continues to deliver training for the greater AD research community in order to provide investigators and trainees with the knowledge and skillsets essential for enabling improved preclinical to clinical translation and accelerate the process of advancing safe and effective therapeutic interventions for AD. HIGHLIGHTS: Translational research is not typically available as a course of study at academic institutions, yet there are fundamental skillsets and knowledge required to enable successful translation from preclinical experiments to clinical efficacy. It is important that there are resources and opportunities available to researchers planning preclinical translational experiments. Here we present proceedings from the fifth annual NIA-sponsored workshop focused on enabling improved preclinical to clinical translation for Alzheimer's disease research that includes didactic lectures on state-of-the-field approaches and hands-on practicums for acquiring essential translational laboratory techniques.

Sex, racial, and APOE-ε4 allele differences in longitudinal white matter microstructure in multiple cohorts of aging and Alzheimer's disease

INTRODUCTION

The effects of sex, race, and Apolipoprotein E (APOE) - Alzheimer's disease (AD) risk factors - on white matter integrity are not well characterized.

METHODS

Diffusion MRI data from nine well-established longitudinal cohorts of aging were free-water (FW)-corrected and harmonized. This dataset included 4,702 participants (age=73.06 ± 9.75) with 9,671 imaging sessions over time. FW and FW-corrected fractional anisotropy (FAFWcorr) were used to assess differences in white matter microstructure by sex, race, and APOE-ε4 carrier status.

RESULTS

Sex differences in FAFWcorr in association and projection tracts, racial differences in FAFWcorr in projection tracts, and APOE-ε4 differences in FW limbic and occipital transcallosal tracts were most pronounced.

DISCUSSION

There are prominent differences in white matter microstructure by sex, race, and APOE-ε4 carrier status. This work adds to our understanding of disparities in AD. Additional work to understand the etiology of these differences is warranted.

The influence of APOE status on rate of cognitive decline

BACKGROUND

Apolipoprotein (APOE) ɛ4 positivity and subjective cognitive decline (SCD) both increase risk of Alzheimer's disease (AD) development. However, few studies have examined the relationship between SCD and APOE status, especially using longitudinal data. The current study examined whether APOE is associated with the rate of cognitive change in SCD and mild cognitive impairment (MCI).

METHODS

A sample of 3494 older adults (1990 normal controls, NC, 775 SCD, and 729 MCI) with a mean follow-up of 9.09 years were included from the Rush Alzheimer's Disease Center Research Sharing Hub. Linear mixed effects models examined the relationship between APOE status and cognitive change in older adults with SCD normal controls, and people with MCI.

RESULTS

The presence of at least one ɛ2 allele in SCD and MCI results in cognitive change rates similar to a NC with the ɛ3ɛ3 genotype. Older adult SCD-ɛ4 individuals exhibited increased rate of cognitive decline compared to all groups, including NC-ɛ4 and MCI-ɛ4.

CONCLUSION

People with SCD with at least one ɛ4 allele experience increased rates of cognitive decline compared to cognitively healthy older adults and people with MCI. These findings have important implications for treatments and interventions and can improve future research and clinical trials by targeting people in the preclinical AD phase (i.e., SCD) who also possess at least one APOE ɛ4 allele.

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.

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.

Recruiting a prospective community cohort to study Alzheimer's disease and structural and social determinants of health among adults racialized as Black: The ARCHES cohort

INTRODUCTION

This ongoing, prospective study examines the effectiveness of methods used to successfully recruit and retain 238 Black older adults in a longitudinal, observational Alzheimer's disease (AD) study.

METHODS

Recruitment strategies included traditional media, established research registries, speaking engagements, community events, and snowball sampling. Participants were asked to complete an annual office testing session, blood-based biomarker collection, optional one-time magnetic resonance imaging (MRI) scan, and community workshop.

RESULTS

Within the first 22 months of active recruitment, 629 individuals expressed interest in participating, and 238 enrolled in the ongoing study. Of the recruitment methods used, snowball sampling, community events, and speaking engagements were the most effective.

DISCUSSION

The systemic underrepresentation of Black participants in AD research impacts the ability to generalize research findings and determine the effectiveness and safety of disease-modifying treatments. Research to slow, stop, or prevent AD remains a top priority but requires diversity in sample representation.

Highlights

Provide flexible appointments in the evening or weekends, offering transportation assistance, and allowing participants to complete study visits at alternative locations, such as senior centers or community centers.Continuously monitor and analyze recruitment data to identify trends, challenges, and opportunities for improvement.Implement targeted strategies to recruit participants who are underrepresented based on sex, gender, or education to increase representation.Diversify the research team to include members who reflect the racial and cultural backgrounds of the target population, to enhance trust and rapport with prospective participants.

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.

Untangling a taxonomy of living from the science of the continuum of life

Medical innovation and technologic advances enrich daily living and occur within our normative worlds, that are socially constructed. These advances confront society with critical questions about the nature of human life, laying bare the inadequacies of extant norms and boundaries. Yet, society has been unable to develop consensus about when life ends. Scientific studies highlight that life is best characterized by continua without natural boundaries. Thus, scientific information alone cannot be employed to justify the socially constructed health categories required for setting norms and boundaries. An iterative process that integrates a broad range of non-scientific data with advancing scientific information is needed to facilitate consensus for updating social norms and boundaries. This can lead to a new taxonomy of living across the measurable continuum of life and align our normative worlds with the dizzying pace of medical innovation and advances in technologies transforming the world in which we live.

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.