Brain Aging in African-Americans: The Atherosclerosis Risk in Communities (ARIC) Experience

Cardiovascular disease risk exacerbates brain aging among Hispanic/Latino adults in the SOL-INCA-MRI Study

Background

Cardiovascular disease (CVD) risk factors are highly prevalent among Hispanic/Latino adults, while the prevalence of MRI infarcts is not well-documented. We, therefore, sought to examine the relationships between CVD risk factors and infarcts with brain structure among Hispanic/Latino individuals.

Methods

Participants included 1,886 Hispanic/Latino adults (50-85 years) who underwent magnetic resonance imaging (MRI) as part of the Study of Latinos-Investigation of Neurocognitive Aging-MRI (SOL-INCA-MRI) study. CVD risk was measured approximately 10.5 years before MRI using the Framingham cardiovascular risk score, a measure of 10-year CVD risk (low (<10%), medium (10- < 20%), and high (≥20%)). MR infarcts were determined as present or absent. Outcomes included total brain, cerebral and lobar cortical gray matter, hippocampal, lateral ventricle, and total white matter hyperintensity (WMH) volumes. Linear regression models tested associations between CVD risk and infarct with MRI outcomes and for modifications by age and sex.

Results

Sixty percent of participants were at medium or high CVD risk. Medium and high CVD risk were associated with lower total brain and frontal gray matter and higher WMH volumes compared to those with low CVD risk. High CVD risk was additionally associated with lower total cortical gray matter and parietal volumes and larger lateral ventricle volumes. Men tended to have greater CVDRF-related differences in total brain volumes than women. The association of CVD risk factors on total brain volumes increased with age, equal to an approximate 7-year increase in total brain aging among the high-CVD-risk group compared to the low-risk group. The presence of infarct(s) was associated with lower total brain volumes, which was equal to an approximate 5-year increase in brain aging compared to individuals without infarcts. Infarcts were also associated with smaller total cortical gray matter, frontal and parietal volumes, and larger lateral ventricle and WMH volumes.

Conclusion

The high prevalence of CVD risk among Hispanic/Latino adults may be associated with accelerated brain aging.

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.

Central arterial stiffness, brain white matter hyperintensity and total brain volume across the adult lifespan

OBJECTIVES

Mounting evidence suggests that central arterial stiffening is associated with brain ageing in older adults. The purpose of this study was to determine the associations of age with carotid arterial stiffness and carotid-femoral pulse wave velocity (cfPWV), both measurements of central arterial stiffness, the relationship between age-related arterial stiffness, brain white matter hyperintensity (WMH) and total brain volume (TBV), and whether effects of central arterial stiffness on WMH volume and TBV are mediated by pulsatile cerebral blood flow (CBF).

METHODS

One hundred and seventy-eight healthy adults (21-80 years) underwent measurements of central arterial stiffness using tonometry and ultrasonography, WMH and TBV via MRI, and pulsatile CBF at the middle cerebral artery via transcranial Doppler.

RESULTS

Advanced age was associated with increases in both carotid arterial stiffness and cfPWV, increases in WMH volume and decreases in TBV (all P  < 0.01). Multiple linear regression analysis showed that carotid β-stiffness was positively associated with WMH volume (B = 0.015, P  = 0.017) and cfPWV negatively with TBV (B = -0.558, P  < 0.001) after adjustment for age, sex and arterial pressure. Pulsatile CBF mediates the associations between carotid β-stiffness and WMH (95% confidence interval: 0.0001-0.0079).

CONCLUSION

These findings suggest that age-related central arterial stiffness is associated with increased WMH volume and decreased TBV, which is likely mediated by increased arterial pulsation.

Cognitive Impairment is Common in a Veterans Affairs Population with Peripheral Arterial Disease

BACKGROUND

Despite the shared pathogenesis of peripheral arterial disease (PAD) and vascular dementia, there are little data on cognitive impairment in PAD patients. We hypothesized that cognitive impairment will be common and previously unrecognized.

METHODS

Cognitive impairment screening was prospectively performed for veterans presenting to a single Veterans Affairs outpatient vascular surgery clinic from 2020-2021 for PAD consultation or disease surveillance. Overall, 125 Veterans were screened. Cognitive impairment was defined as a score of <26 on the Montreal Cognitive Assessment (MoCA) survey. A multivariable logistic regression assessed for independent risk factors for cognitive impairment.

RESULTS

Overall, 77 (61%) had cognitive impairment, 92% was previously unrecognized. Cognitive impairment was associated with increased age (74.4 vs. 71.8 years, P = 0.03), Black versus White race (94% vs. 54%, P < 0.01), hypertension (66% vs. 31%, P = 0.01), prior stroke/TIA (79% vs. 58%, P = 0.03), diabetes treated with insulin (79% vs. 58%, P = 0.05), and post-traumatic stress disorder (PTSD) (80% vs. 57%, P = 0.04). On multivariable analysis, risk factors for newly diagnosed cognitive impairment included age ≥70 years, diabetes treated with insulin, PTSD, and Black race.

CONCLUSIONS

Many veterans with PAD have evidence of cognitive impairment and is overwhelmingly underdiagnosed. This study suggests cognitive impairment is an unrecognized issue in a VA population with PAD, requiring more study to determine cognitive impairment's impact on surgical outcomes, and how it can be mitigated and incorporated into clinical care.

Multimodal imaging of the aging brain: Baseline findings of the LoCARPoN study

We quantified and investigated multimodal brain MRI measures in the LoCARPoN Study due to lack of normative data among Indians. A total of 401 participants (aged 50-88 years) without stroke or dementia completed MRI investigation. We assessed 31 brain measures in total using four brain MRI modalities, including macrostructural (global & lobar volumes, white matter hyperintensities [WMHs]), microstructural (global and tract-specific white matter fractional anisotropy [WM-FA] and mean diffusivity [MD]) and perfusion measures (global and lobar cerebral blood flow [CBF]). The absolute brain volumes of males were significantly larger than those of females, but such differences were relatively small (<1.2% of intracranial volume). With increasing age, lower macrostructural brain volumes, lower WM-FA, greater WMHs, higher WM-MD were found (P = 0.00018, Bonferroni threshold). Perfusion measures did not show significant differences with increasing age. Hippocampal volume showed the greatest association with age, with a reduction of approximately 0.48%/year. This preliminary study augments and provides insight into multimodal brain measures during the nascent stages of aging among the Indian population (South Asian ethnicity). Our findings establish the groundwork for future hypothetical testing studies.

Sex differences in predictors and regional patterns of brain age gap estimates

The brain-age-gap estimate (brainAGE) quantifies the difference between chronological age and age predicted by applying machine-learning models to neuroimaging data and is considered a biomarker of brain health. Understanding sex differences in brainAGE is a significant step toward precision medicine. Global and local brainAGE (G-brainAGE and L-brainAGE, respectively) were computed by applying machine learning algorithms to brain structural magnetic resonance imaging data from 1113 healthy young adults (54.45% females; age range: 22-37 years) participating in the Human Connectome Project. Sex differences were determined in G-brainAGE and L-brainAGE. Random forest regression was used to determine sex-specific associations between G-brainAGE and non-imaging measures pertaining to sociodemographic characteristics and mental, physical, and cognitive functions. L-brainAGE showed sex-specific differences; in females, compared to males, L-brainAGE was higher in the cerebellum and brainstem and lower in the prefrontal cortex and insula. Although sex differences in G-brainAGE were minimal, associations between G-brainAGE and non-imaging measures differed between sexes with the exception of poor sleep quality, which was common to both. While univariate relationships were small, the most important predictor of higher G-brainAGE was self-identification as non-white in males and systolic blood pressure in females. The results demonstrate the value of applying sex-specific analyses and machine learning methods to advance our understanding of sex-related differences in factors that influence the rate of brain aging and provide a foundation for targeted interventions.

Association Between Estimated Pulse Wave Velocity and Cognitive Performance in Older Black and White Adults in NHANES

BACKGROUND

Aging-associated cognitive decline is greater in non-Hispanic Black (NHB) adults than non-Hispanic White (NHW) adults. An important risk factor for cognitive decline with aging is arterial stiffening, though the importance to racial variation remains poorly understood.

OBJECTIVE

We examined the association of an estimate of arterial stiffness with cognitive function in a bi-racial sample of 60-85-year-old adults (N = 3,616, 26.5% NHB) enrolled in the National Health and Nutrition Examination Survey (NHANES) between 1999-2002 and 2011-2014.

METHODS

As a measure of vascular aging, pulse wave velocity was estimated (ePWV) using an equation incorporating age and mean arterial pressure and expressed as m/s. Using the digit symbol substitution test (DSST), cognitive function was expressed as the number of correctly matched symbols (out of 133) within 120 s. Linear regression models examined associations between ePWV and DSST.

RESULTS

In models that adjusted for sex, education, smoking, body mass index, history of cardiovascular disease, and hypertension, ePWV was inversely associated with DSST score in NHB adults (β= -3.47, 95% CI = -3.9 to -3.0; p <  0.001) and NHW adults (β= -3.51, 95% CI = -4.4 to -2.6; p <  0.001).

CONCLUSION

ePWV is inversely associated with a measure of cognitive function in older Black and White adults. ePWV may be a useful measure of vascular aging that can offer insight into cognitive aging.

Vascular Cognitive Impairment and Dementia

PURPOSE OF REVIEW

This article gives a broad overview of vascular cognitive impairment and dementia, including epidemiology, pathophysiology, clinical approach, and management. Emphasis is placed on understanding the common underlying types of cerebrovascular disease (including atherosclerosis, arteriolosclerosis, and cerebral amyloid angiopathy) and awareness of rare inherited cerebrovascular disorders.

RECENT FINDINGS

The pathophysiology of vascular cognitive impairment and dementia is heterogeneous, and the most recent diagnostic criteria for vascular cognitive impairment and dementia break down the diagnosis of major vascular dementia into four phenotypic categories, including subcortical ischemic vascular dementia, poststroke dementia, multi-infarct dementia, and mixed dementia. Control of cardiovascular risk factors, including management of midlife blood pressure, cholesterol, and blood sugars, remains the mainstay of prevention for vascular cognitive impairment and dementia. Cerebral amyloid angiopathy requires special consideration when it comes to risk factor management given the increased risk of spontaneous intracerebral hemorrhage. Recent trials suggest some improvement in global cognitive function in patients with vascular cognitive impairment and dementia with targeted cognitive rehabilitation.

SUMMARY

Thorough clinical evaluation and neuroimaging form the basis for diagnosis. As vascular cognitive impairment and dementia is the leading nondegenerative cause of dementia, identifying risk factors and optimizing their management is paramount. Once vascular brain injury has occurred, symptomatic management should be offered and secondary prevention pursued.

Association of Brain Volumes and White Matter Injury With Race, Ethnicity, and Cardiovascular Risk Factors: The Multi-Ethnic Study of Atherosclerosis

Background Cardiovascular risk factors are associated with cognitive decline and dementia. Magnetic resonance imaging provides sensitive measurement of brain morphology and vascular brain injury. However, associations of risk factors with brain magnetic resonance imaging findings have largely been studied in White participants. We investigated associations of race, ethnicity, and cardiovascular risk factors with brain morphology and white matter (WM) injury in a diverse population. Methods and Results In the Multi-Ethnic Study of Atherosclerosis, measures were made in 2018 to 2019 of total brain volume, gray matter and WM volume, and WM injury, including WM hyperintensity volume and WM fractional anisotropy. We assessed cross-sectional associations of race and ethnicity and of cardiovascular risk factors with magnetic resonance imaging measures. Magnetic resonance imaging data were complete in 1036 participants; 25% Black, 15% Chinese-American, 19% Hispanic, and 41% White. Mean (SD) age was 72 (8) years and 53% were women. Although WM injury was greater in Black than in White participants in a minimally adjusted model, additional adjustment for cardiovascular risk factors and socioeconomic status each attenuated this association, rendering it nonsignificant. Overall, greater average WM hyperintensity volume was associated with older age and current smoking (69% greater vs never smoking); lower fractional anisotropy was additionally associated with higher diastolic blood pressure, use of antihypertensive medication, and diabetes. Conclusions We found no statistically significant difference in measures of WM injury by race and ethnicity after adjustment for cardiovascular risk factors and socioeconomic status. In all racial and ethnic groups, older age, current smoking, hypertension, and diabetes were strongly associated with WM injury.

Exposing the Brain Proteomic Signatures of Alzheimer's Disease in Diverse Racial Groups: Leveraging Multiple Data Sets and Machine Learning

Recent studies have highlighted that the proteome can be used to identify potential biomarker candidates for Alzheimer's disease (AD) in diverse cohorts. Furthermore, the racial and ethnic background of participants is an important factor to consider to ensure the effectiveness of potential biomarkers for representative populations. A promising approach to survey potential biomarker candidates for diagnosing AD in diverse cohorts is the application of machine learning to proteomics data sets. Herein, we leveraged six existing bottom-up proteomics data sets, which included non-Hispanic White, African American/Black, and Hispanic participants, to study protein changes in AD and cognitively unimpaired participants. Machine learning models were applied to these data sets and resulted in the identification of amyloid-β precursor protein (APP) and heat shock protein β-1 (HSPB1) as two proteins that have high ability to distinguish AD; however, each protein's performance varied based upon the racial and ethnic background of the participants. HSPB1 particularly was helpful for generating high areas under the curve (AUCs) for African American/Black participants. Overall, HSPB1 improved the performance of the machine learning models when combined with APP and/or participant age and is a potential candidate that should be further explored in AD biomarker discovery efforts.

ABCA7, a Genetic Risk Factor Associated with Alzheimer's Disease Risk in African Americans

African American/Black adults are twice as likely to have Alzheimer's disease (AD) compared to non-Hispanic White adults. Genetics partially contributes to this disparity in AD risk, among other factors, as there are several genetic variants associated with AD that are more prevalent in individuals of African or European ancestry. The phospholipid-transporting ATPase ABCA7 (ABCA7) gene has stronger associations with AD risk in individuals with African ancestry than in individuals with European ancestry. In fact, ABCA7 has been shown to have a stronger effect size than the apolipoprotein E (APOE) ɛ4 allele in African American/Black adults. ABCA7 is a transmembrane protein involved in lipid homeostasis and phagocytosis. ABCA7 dysfunction is associated with increased amyloid-beta production, reduced amyloid-beta clearance, impaired microglial response to inflammation, and endoplasmic reticulum stress. This review explores the impact of ABCA7 mutations that increase AD risk in African American/Black adults on ABCA7 structure and function and their contributions to AD pathogenesis. The combination of biochemical/biophysical and 'omics-based studies of these variants needed to elucidate their downstream impact and molecular contributions to AD pathogenesis is highlighted.

Ethnic Variation in the Manifestation of Parkinson's Disease: A Narrative Review

The global prevalence of Parkinson's disease is increasing, yet the characteristics, risk factors and genetics of PD in Black, Asian and Hispanic populations is little understood. In this paper we review the published literature on clinical variation in the symptoms and signs of Parkinson's disease in different ethnic groups and responses to treatment. We included any study that sampled patients with Parkinson's disease from distinct ethnic backgrounds. We conclude that whilst there is little published evidence for ethnic variation in the clinical features of Parkinson's disease, there are substantial limitations and gaps in the current literature, which mean that the evidence does necessarily not fit with clinical observation. Possible explanations for expected differences in manifestation include genetic determinants, the co-existence of cerebrovascular disease and/or Alzheimer's disease pathology, healthcare inequalities and socio-cultural factors.

Racial/Ethnic Disparities in Young Adulthood and Midlife Cardiovascular Risk Factors and Late-life Cognitive Domains: The Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study

BACKGROUND

Midlife cardiovascular risk factors (CVRF) increase dementia risk. Less is known about whether CVRF identified before midlife impact late-life cognition in diverse populations.

METHODS

Linear regression models examined hypertension, hyperlipidemia, and overweight/obesity at ages 30 to 59 with late-life executive function, semantic memory, verbal episodic memory, and global cognition in a cohort of Asians, blacks, Latinos, and whites (n=1127; mean age=75.8, range=65 to 98). Models adjusted for age at CVRF, age at cognitive assessment, sex, race/ethnicity, participant education, and parental education.

RESULTS

Overall, 34% had 1 CVRF at ages 30 to 59; 19% had 2+. Blacks (26%) and Latinos (23%) were more likely to have 2+ CVRF than Asians (14%) or whites (13%). Having 2+ CVRF was associated with lower global cognition [β=-0.33; 95% confidence interval (CI)=-0.45, -0.21], executive function (β=-0.26; 95% CI=-0.39, -0.13), verbal episodic memory (β=-0.34; 95% CI=-0.48, -0.20), and semantic memory (β=-0.20; 95% CI=-0.33, -0.07). Interaction by age (P=0.06) indicated overweight/obesity was negatively associated with executive function at ages 30 to 39 but not at ages 40 to 59. Race/ethnic-specific effects showed disparities in CVRF prevalence impact population disparities in late-life cognition.

CONCLUSION

Being overweight/obese in early adulthood and having 2+ CVRF in early adulthood/midlife are modifiable targets to redress racial/ethnic disparities in cognitive impairment and dementia.

Building research in diet and cognition (BRIDGE): Baseline characteristics of older obese African American adults in a randomized controlled trial to examine the effect of the Mediterranean diet with and without weight loss on cognitive functioning

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The MedDiet is correlated with slower cognitive decline in longitudinal studies.

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Self-reported MedDiet adherence positively associated with select cognitive domains.

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Women outperformed men across verbal tasks, including learning and memory.

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Younger participants outperformed older participants on cognitive assessments.

In the United States, >5.4 million people age 65 and older are affected by cognitive impairment and dementia, including Alzheimer’s disease. African Americans are more likely than non-Hispanic whites to suffer from these disorders. Obesity is linked to accelerated age-related cognitive decline, and weight loss through caloric restriction is a potential strategy to prevent this cognitive impairment. Adherence to a healthful dietary pattern, such as the Mediterranean Diet (MedDiet), has also shown positive effects on reducing risk for dementia. African Americans are disproportionately affected by obesity and have less healthful diets than non-Hispanic whites. We present baseline characteristics from a three-arm randomized controlled trial that randomized 185 obese (BMI ≥ 30 kg/m² and ≤ 50 kg/m²) healthy older adults (55–85 years of age) to: 1) Typical Diet Control (TDC); 2) MedDiet alone (MedDiet-A) intervention; or 3) MedDiet caloric restricted intervention to promote weight loss (MedDiet-WL). The majority of the sample was African American (91.4%) and female (85.9%). The two active interventions (MedDiet-A and MedDiet-WL) met once weekly for 8 months, and the TDC received weekly general health newsletters. Baseline data were collected between January 2017 and July 2019 in Chicago, IL. In our sample, closer adherence to a MedDiet pattern was associated with higher attention and information processing (AIP) and higher executive functioning (EF). Consistent with the literature, we saw that older participants performed more poorly on the cognitive assessments than younger participants, and women outperformed men across verbally mediated tasks, especially ones related to learning and memory.

A Pooled Analysis of Diffusion-Weighted Imaging Lesions in Patients With Acute Intracerebral Hemorrhage

Importance

The etiology and significance of diffusion-weighted imaging (DWI) lesions in patients with acute intracerebral hemorrhage (ICH) remain unclear.

Objective

To evaluate which factors are associated with DWI lesions, whether associated factors differ by ICH location, and whether DWI lesions are associated with functional outcomes.

Design, Setting, and Participants

This analysis pooled individual patient data from 3 randomized clinical trials (Minimally Invasive Surgery Plus Alteplase for Intracerebral Hemorrhage Evacuation phase 3 trial, Antihypertensive Treatment of Acute Cerebral Hemorrhage trial, and Intracerebral Hemorrhage Deferoxamine phase 2 trial) and 1 multicenter prospective study (Ethnic/Racial Variations of Intracerebral Hemorrhage). Patients were enrolled from August 1, 2010, to September 30, 2018. Of the 4782 patients, 1788 who underwent magnetic resonance imaging scans of the brain were included. Data were analyzed from July 1 to December 31, 2019.

Main Outcomes and Measures

The primary outcome consisted of factors associated with DWI lesions. Secondary outcomes were poor functional outcome, defined as a modified Rankin score (mRS) of 4 to 6, and mortality, both assessed at 3 months. Mixed-effects logistic regression was used to evaluate the association between exposures and outcomes. Subgroup analyses stratified by hematoma location were performed.

Results

After exclusion of 36 patients with missing data on DWI lesions, 1752 patients were included in the analysis (1019 men [58.2%]; mean [SD] age, 60.8 [13.3] years). Diffusion-weighted imaging lesions occurred in 549 patients (31.3%). In mixed-effects regression models, factors associated with DWI lesions included younger age (odds ratio [OR] per year, 0.98; 95% CI, 0.97-0.99), black race (OR, 1.64; 95% CI, 1.17-2.30), admission systolic blood pressure (OR per 10-mm Hg increase, 1.13; 95% CI, 1.08-1.18), baseline hematoma volume (OR per 10-mL increase, 1.12; 95% CI, 1.02-1.22), cerebral microbleeds (OR, 1.85; 95% CI, 1.39-2.46), and leukoaraiosis (OR, 1.59; 95% CI, 1.67-2.17). Diffusion-weighted imaging lesions were independently associated with poor mRS (OR, 1.50; 95% CI, 1.13-2.00), but not with mortality (OR, 1.11; 95% CI, 0.72-1.71). In subgroup analyses, similar factors were associated with DWI lesions in lobar and deep ICH. Diffusion-weighted imaging lesions were associated with poor mRS in deep but not lobar ICH.

Conclusions and Relevance

In a large, heterogeneous cohort of prospectively identified patients with ICH, results were consistent with the hypothesis that DWI lesions represent acute sequelae of chronic cerebral small vessel disease, particularly hypertensive vasculopathy. Diffusion-weighted imaging lesions portend a worse prognosis after ICH, mainly deep hemorrhages.

Association of Ventricular Arrhythmias With Dementia: The Atherosclerosis Risk in Communities (ARIC) Study

OBJECTIVE

We performed a cross-sectional analysis to determine whether nonsustained ventricular tachycardia (NSVT) and premature ventricular contractions (PVCs) were associated with dementia in a population-based study.

METHODS

We included 2,517 (mean age 79 years, 26% Black) participants who wore a 2-week ambulatory continuous ECG recording device in 2016 to 2017. NSVT was defined as a wide-complex tachycardia ≥4 beats with a rate >100 bpm. We calculated NSVT and PVC burden as the number of episodes per day. Dementia was adjudicated by experts. We used logistic regression to assess the associations of NSVT and PVCs with dementia.

RESULTS

The mean recording time of the Zio XT Patch was 12.6 ± 2.6 days. There were 768 (31%) participants with NSVT; prevalence was similar in White and Black participants. There were 134 (6.5%) dementia cases (5% in White, 10% in Black participants). After multivariable adjustment, there was no overall association between NSVT and dementia; however, there was a significant race interaction (p < 0.001). In Black participants, NSVT was associated with a 3.67 times higher adjusted odds of dementia (95% confidence interval [CI] 1.92-7.02) compared to those without NSVT, whereas in White participants NSVT was not associated with dementia (odds ratio [95% CI] 0.64 [0.37-1.10]). In Black participants only, a higher burden of PVCs was associated with dementia.

CONCLUSIONS

Presence of NSVT and a higher burden of NSVT and PVCs are associated with dementia in elderly Black people. Further research to confirm this novel finding and to elucidate the underlying mechanisms is warranted.

Vascular Cellular Adhesion Molecule-1 (VCAM-1) and Memory Impairment in African-Americans after Small Vessel-Type Stroke

BACKGROUND

African-Americans (AA) are 3 times more likely to have small-vessel-type ischemic strokes (SVS) than Whites. Small vessel strokes are associated with cognitive impairment, a relationship incompletely explained by white matter hyperintensity (WMH) burden. We examined whether inflammatory/endothelial dysfunction biomarkers are associated with cognition after SVS in AAs.

METHODS

Biomarkers were obtained in 24 subjects (median age 56.5 years, 54% women, median 12 years education). Cognition was assessed more than 6 weeks poststroke using the memory composite score (MCS), which was generated using recall from the Hopkins Verbal Learning Test-II and Brief Visuospatial Memory Test-Revised. A semi-automated, volumetric protocol was used to quantify WMH volume (WMHv) on clinical MRI scans. Potential biomarkers including vascular cell adhesion molecule-1 (VCAM-1), interleukin-1 receptor antagonist, interleukin-6, interleukin-8, interleukin-10, interferon gamma, and thrombin-antithrombin (TAT) were log-transformed and correlated with MCS with adjustment for potential confounders.

RESULTS

Among serum biomarkers, only VCAM-1-correlated with poorer memory based on the MCS (r = -.659; P = .0006). VCAM-1 (r = .554; P = .005) and age (r = .479; P = .018) correlated with WMHv; VCAM-1 was independently associated with MCS after adjustment for WMHv, age, and education (P = .023).

CONCLUSIONS

The findings of this exploratory analysis suggest that endothelial dysfunction and inflammation as reflected by VCAM-1 levels may play a role in poststroke cognitive impairment. Additional studies are needed to validate this observation and to evaluate this relationship in non-AAs and with other stroke types and compare this finding to cognitive impairment in nonstroke populations.

Examining Cognitive Decline Across Black and White Participants in the Harvard Aging Brain Study

BACKGROUND

Black Americans are approximately twice as likely to develop dementia as compared to White Americans and the magnitude of this disparity is often attributed to a variety of factors that include psychosocial and vascular risk factors. However, less is known about the potential contribution of Alzheimer's disease pathological differences.

OBJECTIVE

To examine potential differences incross-sectional and longitudinal cognitive performance in black and white participants who were clinically normal at baseline.

METHODS

296 participants (48 African-American/black participants) underwent MRI and amyloid PET at baseline. Linear mixed models were used to examine the main effects of race, years of education, reading ability, Framingham Heart Study cardiovascular risk score (FHS-CVD), white matter hyperintensities (WMH), and amyloid (Aβ) burden on the Preclinical Alzheimer Cognitive Composite-5 (PACC5).

RESULTS

Lower levels of educationalattainment and reading ability were found for blacks compared to whites. By contrast, no differences in FHS-CVD, WMH, or Aβ were found by racial group. Baseline differences in PACC5 score were attenuated after adjusting for educationalfactors, vascular factors, and Aβ, but remained lower for blacks compared to whites (β= -0.24, p = 0.014). Further, blacks demonstrated a faster rate of PACC5 decline longitudinally compared to whites (β  = -0.055, p = 0.025) after adjusting for covariates.

CONCLUSION

Accounting for educationalfactors, vascular factors, and Aβ burden diminished, but did not eliminate, racial differences in PACC5 performance longitudinally. Understanding potential differences in longitudinal cognitive outcomes by race may be important for upcoming secondary prevention trials.

Patterns of Dementia Treatment and Frank Prescribing Errors in Older Adults With Parkinson Disease

Importance

Dementia is common in Parkinson disease, but few data exist on dementia treatment patterns or the concurrent use of acetylcholinesterase inhibitors (ACHEIs) and anticholinergic medications, a frank prescribing error.

Objectives

To describe dementia treatment patterns, and to determine the extent to which the concurrent use of ACHEIs and drugs with strong anticholinergic activity occurs among individuals with Parkinson disease in the United States.

Design, Setting, and Participants

This cross-sectional analysis included adult Medicare beneficiaries (aged 65 years or older) with Parkinson disease diagnosis with 12 consecutive months of inpatient, outpatient, and prescription drug coverage from January 1, 2014, through December 31, 2014. Beneficiaries with other parkinsonian syndromes were excluded. Demographic, geographic, prescription claims, and other data were extracted from the 2014 Carrier, Beneficiary Summary, and Prescription Drug Event research identifiable files of the Centers for Medicare & Medicaid Services. Data analysis was conducted from August 1, 2017, to November 30, 2017.

Main Outcomes and Measures

Primary outcomes were use of dementia drug, specific dementia medication, and concurrent exposure to a high-potency anticholinergic drug and an ACHEI. Descriptive analyses and multivariable logistic regression models determined the extent to which patient characteristics and comorbid conditions were associated with dementia treatment or with a high-potency anticholinergic and ACHEI never event.

Results

Of 268 407 Medicare beneficiaries with Parkinson disease (mean [SD] age, 78.9 [7.5]; 134 575 male [50.1%]), most were identified in the files as white (232 831 [86.7%]), followed by black (14 629 [5.5%]), Hispanic (7176 [2.7%]), Asian (7115 [2.7%]), and Native American (874 [0.3%]). Among these beneficiaries, 73 093 (27.2%) were given a prescription for at least 1 antidementia medication. The most commonly prescribed medication was donepezil hydrochloride (46 027 [63.0%] users), followed by memantine hydrochloride (30 578 [41.8%] users) and rivastigmine tartrate (19 278 [26.4%] users). Dementia drugs were more likely to be prescribed to black (adjusted odds ratio [AOR], 1.33; 95% CI, 1.28-1.38) and Hispanic (AOR, 1.28; 95% CI, 1.22-1.35) beneficiaries and less likely for Native American beneficiaries (AOR, 0.62; 95% CI, 0.51-0.74). Women were less likely than men to be given a prescription for dementia medication (AOR, 0.85; 95% CI, 0.84-0.87). Of the 64 017 beneficiaries receiving an ACHEI, 28 495 (44.5%) experienced at least 1 high-potency anticholinergic-ACHEI event. Hispanic (AOR, 1.11; 95% CI, 1.00-1.23) and women (AOR, 1.30; 95% CI, 1.25-1.35) beneficiaries had greater odds of experiencing this never event. Statistically significant clusters of the prevalence of this prescribing error were observed across the United States (Moran I = 0.24; P < .001), with clusters of high prevalence in the southern and midwestern states.

Conclusions and Relevance

Dementia medication use by persons with Parkinson disease varies by race/ethnicity and sex; potentially inappropriate prescribing is common among those being treated for cognitive impairment and varies by race/ethnicity, sex, and geography. These findings may serve as national and local targets for improving care quality and outcomes for persons with Parkinson disease.

Cerebral Amyloid Angiopathy: Similarity in African-Americans and Caucasians with Alzheimer's Disease

Cerebral amyloid angiopathy (CAA) of the Aβ type is variably present in the brains of patients with Alzheimer's disease (AD). CAA contributes to cognitive decline and increases the risk of lobar hemorrhage; because both AD-typical dementia and lobar hemorrhage are more common in African-Americans than in Caucasians, we postulated that African-Americans with AD might be particularly susceptible to CAA. To test this hypothesis, we analyzed CAA histopathologically in the large vessels and capillaries of autopsy-derived frontal, temporal, parietal, and occipital cortical samples from African-Americans (n = 18) and Caucasians (n = 19) with end-stage AD. In the combined cohort of 37 subjects, 22% of the subjects had severe CAA in large vessels, and 11% had severe CAA in capillaries. However, the prevalence and histopathologic characteristics of CAA were similar in the African-Americans and Caucasians. This conclusion was substantiated in an independent sample from the National Alzheimer's Coordinating Center database, in which the degree of CAA was comparable in 1,554 Caucasians and 68 African-Americans with end-stage AD. These findings support a growing consensus that the fundamental histopathologic features of AD are largely impartial to the race of the afflicted.

Strategies for the Recruitment and Retention of Racial/Ethnic Minorities in Alzheimer Disease and Dementia Clinical Research

Background:

Racial/ethnic minorities have among the highest risks for Alzheimer disease and dementia, but remain underrepresented in clinical research studies.

Objective:

To synthesize the current evidence on strategies to recruit and retain racial/ethnic minorities in Alzheimer disease and dementia clinical research.

Methods:

We conducted a systematic review by searching CINAHL, EMBASE, MEDLINE, PsycINFO, and Scopus. We included studies that met four criteria: (1) included a racial/ethnic minority group (African American, Latino, Asian, American Indian or Alaska Native, and Native Hawaiian or Other Pacific Islander); (2) implemented a recruitment or retention strategy for Alzheimer disease or dementia clinical research; (3) conducted within the U.S.; and (4) published in a peer-reviewed journal.

Results:

Of the 19 included studies, 14 (73.7%) implemented recruitment strategies and 5 (26.3%) implemented both recruitment and retention strategies. Fifteen studies (78.9%) focused on African Americans, two (10.6%) on both African Americans and Latinos, and two (10.5%) on Asians. All the articles were rated weak in the study quality. Four major themes were identified for the recruitment strategies: community outreach (94.7%), advertisement (57.9%), collaboration with health care providers (42.1%), and referral (21.1%). Three major themes were identified for the retention strategies: follow-up communication (15.8%), maintain community relationship (15.8%), and convenience (10.5%).

Conclusion:

Our findings highlight several promising recruitment and retention strategies that investigators should prioritize when allocating limited resources, however, additional well-designed studies are needed. By recruiting and retaining more racial/ethnic minorities in Alzheimer disease and dementia research, investigators may better understand the heterogeneity of disease progression among marginalized groups. PROSPERO registration #CRD42018081979.

Things Are Changing so Fast: Integrative Technology for Preserving Cognitive Health and Community History

Background and Objectives

Multimodal interventions are increasingly targeting multiple cognitive decline risk factors. However, technology remains mostly adjunctive, largely prioritizes age relevancy over cultural relevancy, and often targets individual health without lasting, community-wide deliverables. Meanwhile, African Americans remain overburdened by cognitive risk factors yet underrepresented in cognitive health and technology studies. The Sharing History through Active Reminiscence and Photo-imagery (SHARP) program increases physical, social, and cognitive activity within a culturally meaningful context that produces community deliverables-an oral history archive and cognitive health education.

Design and Methods

The SHARP application was tested with 19 African Americans ≥55 years, aiming for an easy, integrative, and culturally meaningful experience. The application guided triads in walks 3 times weekly for 6 months in Portland, Oregon's historically Black neighborhoods; local historical images prompted recorded conversational reminiscence. Focus groups evaluated factors influencing technology acceptance-attitudes about technology, usefulness, usability, and relevance to integrating program goals. Thematic analysis guided qualitative interpretation.

Results

Technology acceptance was influenced by group learning, paper-copy replicas for reluctant users, ease of navigation, usefulness for integrating and engaging in health behaviors, relevance to integrating individual benefit and the community priority of preserving history amidst gentrification, and flexibility in how the community uses deliverables. Perceived community benefits sustained acceptance despite intermittent technology failure.

Discussion and Implications

We offer applicable considerations for brain health technology design, implementation, and deliverables that integrate modalities, age, and cultural relevance, and individual and community benefit for more meaningful, and thus more motivated community engagement.

White Matter Lesions Predict Recurrent Vascular Events in Patients with Transient Ischemic Attacks

Background:

White matter lesions (WMLs) are common findings in brain magnetic resonance imaging (MRI) and are strongly associated with stroke incidence, recurrence, and prognosis. However, the relationship between WMLs and transient ischemic attacks (TIAs) is not well established. This study aimed to determine the clinical significance of WMLs in patients with TIA.

Methods:

A total of 181 consecutive inpatients with first-ever TIA were enrolled. Brain MRIs within 2 days of symptom onset were used to measure WML volumes. Recurrent vascular events within 1 year of TIA onset were assessed. The relationship between WMLs and recurrent risk of vascular events was determined by a multivariate logistic regression.

Results:

WMLs were identified in 104 patients (57.5%). Age and ratio of hypertension were significantly different between patients with and without WMLs. The incidence of vascular events in patients with WMLs significantly increased in comparison to those without WMLs (21.15% vs. 5.19%, 95% confidence interval [CI]: 1.18–15.20, P = 0.027) after controlling for confounders. Furthermore, distributions of WML loads were found to be different between patients who developed vascular events and those who did not. WML volumes were demonstrated to be correlated with recurrent risks, and the fourth quartile of WML volumes led to an 8.5-fold elevation of recurrent risk of vascular events compared with the first quartile (95% CI: 1.52–47.65, P = 0.015) after adjusting for hyperlipidemia.

Conclusion:

WMLs occur frequently in patients with TIA and are associated with the high risk of recurrent vascular events, suggesting a predictive neuroimaging marker for TIA outcomes.

Effect of Alzheimer's disease risk and protective factors on cognitive trajectories in subjective memory complainers: An INSIGHT-preAD study

INTRODUCTION

Cognitive change in people at risk of Alzheimer's disease (AD) such as subjective memory complainers is highly variable across individuals.

METHODS

We used latent class growth modeling to identify distinct classes of nonlinear trajectories of cognitive change over 2 years follow-up from 265 subjective memory complainers individuals (age 70 years and older) of the INSIGHT-preAD cohort. We determined the effect of cortical amyloid load, hippocampus and basal forebrain volumes, and education on the cognitive trajectory classes.

RESULTS

Latent class growth modeling identified distinct nonlinear cognitive trajectories. Education was associated with higher performing trajectories, whereas global amyloid load and basal forebrain atrophy were associated with lower performing trajectories.

DISCUSSION

Distinct classes of cognitive trajectories were associated with risk and protective factors of AD. These associations support the notion that the identified cognitive trajectories reflect different risk for AD that may be useful for selecting high-risk individuals for intervention trials.

Antihypertensive Medication and Dementia Risk in Older Adult African Americans with Hypertension: A Prospective Cohort Study

BACKGROUND

African Americans are especially at risk of hypertension and dementia. Antihypertensive medications reduce the risk of cardiovascular events, but may also reduce the risk of dementia.

OBJECTIVE

To assess the longitudinal effects of antihypertensive medications and blood pressure on the onset of incident dementia in a cohort of African Americans.

DESIGN

Prospective cohort.

PARTICIPANTS

1236 community-dwelling patients from an inner-city public health care system, aged 65 years and older, with a history of hypertension but no history of dementia, and who had at least three primary care visits and a prescription filled for any medication.

MAIN MEASURES

Blood pressure was the average of three seated measurements. Dementia was diagnosed using a two-stage design, with a screening evaluation every 2 to 3 years followed by a comprehensive in-home clinical evaluation for those with a positive screen. Laboratory, inpatient and outpatient encounter data, coded diagnoses and procedures, and medication records were derived from a health information exchange.

KEY RESULTS

Of the 1236 hypertensive participants without dementia at baseline, 114 (9%) developed incident dementia during follow-up. Individuals prescribed any antihypertensive medication (n = 816) were found to have a significantly reduced risk of dementia (HR = 0.57, 95% CI 0.37-0.88, p = 0.0114) compared to untreated hypertensive participants (n = 420). When this analysis was repeated including a variable indicating suboptimally treated blood pressure (> 140 mmHg systolic or >90 mmHg diastolic), the effect of antihypertensive medication was no longer statistically significant (HR = 0.65, 95% CI 0.32-1.30, p = 0.2217).

CONCLUSIONS

Control of blood pressure in older adult African American patients with hypertension is a key intervention for preventing dementia, with similar benefits from most of the commonly available antihypertensive medications.

Enhancing the Infrastructure of the Atherosclerosis Risk in Communities (ARIC) Study for Cancer Epidemiology Research: ARIC Cancer

Background: We describe the expansion of the Atherosclerosis Risk in Communities (ARIC) Study into a cancer cohort. In 1987 to 1989, ARIC recruited 15,792 participants 45 to 64 years old to be sex (55% female), race (27% black), and geographically diverse. ARIC has exceptional data collected during 6 clinical visits and calls every 6 months, repeated biospecimens, and linkage to Medicare claims data.Methods: We established a Cancer Coordinating Center to implement infrastructure activities, convened a Working Group for data use, leveraged ARIC staff and procedures, and developed protocols. We initiated a cancer-specific participant contact, added questions to existing contacts, obtained permission to collect medical records and tissue, abstracted records, linked with state cancer registries, and adjudicated cases and characterizing data.Results: Through 2012, we ascertained and characterized 4,743 incident invasive, first, and subsequent primary cancers among 4,107 participants and 1,660 cancer-related deaths. We generated a total cancer incidence and mortality analytic case file, and analytic case files for bladder, breast, colorectal, liver, lung, pancreas, and prostate cancer incidence, mortality, and case fatality. Adjudication of multiple data sources improved case records and identified cancers not identified via registries. From 2013 onward, we ascertain cases from self-report coupled with medical records. Additional cancer registry linkages are planned.Conclusions: Compared with starting a new cohort, expanding a cardiovascular cohort into ARIC Cancer was an efficient strategy. Our efforts yielded enhanced case files with 25 years of follow-up.Impact: Now that the cancer infrastructure is established, ARIC is contributing its unique features to modern cancer epidemiology research. Cancer Epidemiol Biomarkers Prev; 27(3); 295-305. ©2017 AACR.

A population neuroscience approach to the study of cerebral small vessel disease in midlife and late life: an invited review

Aging in later life engenders numerous changes to the cerebral microvasculature. Such changes can remain clinically silent but are associated with greater risk for negative health outcomes over time. Knowledge is limited about the pathogenesis, prevention, and treatment of potentially detrimental changes in the cerebral microvasculature that occur with advancing age. In this review, we summarize literature on aging of the cerebral microvasculature, and we propose a conceptual framework to fill existing research gaps and advance future work on this heterogeneous phenomenon. We propose that the major gaps in this area are attributable to an incomplete characterization of cerebrovascular pathology, the populations being studied, and the temporality of exposure to risk factors. Specifically, currently available measures of age-related cerebral microvasculature changes are indirect, primarily related to parenchymal damage rather than direct quantification of small vessel damage, limiting the understanding of cerebral small vessel disease (cSVD) itself. Moreover, studies seldom account for variability in the health-related conditions or interactions with risk factors, which are likely determinants of cSVD pathogenesis. Finally, study designs are predominantly cross-sectional and/or have relied on single time point measures, leaving no clear evidence of time trajectories of risk factors or of change in cerebral microvasculature. We argue that more resources should be invested in 1) developing methodological approaches and basic science models to better understand the pathogenic and etiological nature of age-related brain microvascular diseases and 2) implementing state-of-the-science population study designs that account for the temporal evolution of cerebral microvascular changes in diverse populations across the lifespan.

Associations Between Midlife Vascular Risk Factors and 25-Year Incident Dementia in the Atherosclerosis Risk in Communities (ARIC) Cohort

Importance

Vascular risk factors have been associated with cognitive decline. Midlife exposure to these factors may be most important in conferring late-life risk of cognitive impairment.

Objectives

To examine Atherosclerosis Risk in Communities (ARIC) participants in midlife and to explore associations between midlife vascular risk factors and 25-year dementia incidence.

Design, Setting, and Participants

This prospective cohort investigation of the Atherosclerosis Risk in Communities (ARIC) Study was conducted from 1987-1989 through 2011-2013. The dates of this analysis were April 2015 through August 2016. The setting was ARIC field centers (Washington County, Maryland; Forsyth County, North Carolina; Jackson, Mississippi; and Minneapolis suburbs, Minnesota). The study comprised 15 744 participants (of whom 27.1% were black and 72.9% white) who were aged 44 to 66 years at baseline.

Main Outcomes and Measures

Demographic and vascular risk factors were measured at baseline (obesity, smoking, diabetes, prehypertension, hypertension, and hypercholesterolemia) as well as presence of the APOE ε4 genotype. After the baseline visit, participants had 4 additional in-person visits, for a total of 5 in-person visits, hospitalization surveillance, telephone calls, and repeated cognitive evaluations. Most recently, in 2011-2013, through the ARIC Neurocognitive Study (ARIC-NCS), participants underwent a detailed neurocognitive battery, informant interviews, and adjudicated review to define dementia cases. Additional cases were identified through the Telephone Interview for Cognitive Status-Modified or informant interview, for participants not attending the ARIC-NCS visit, or by an International Classification of Diseases, Ninth Revision dementia code during a hospitalization. Fully adjusted Cox proportional hazards regression was used to evaluate associations of baseline vascular and demographic risk factors with dementia.

Results

In total, 1516 cases of dementia (57.0% female and 34.9% black, with a mean [SD] age at visit 1 of 57.4 [5.2] years) were identified among 15 744 participants. Black race (hazard ratio [HR], 1.36; 95% CI, 1.21-1.54), older age (HR, 8.06; 95% CI, 6.69-9.72 for participants aged 60-66 years), lower educational attainment (HR, 1.61; 95% CI, 1.28-2.03 for less than a high school education), and APOE ε4 genotype (HR, 1.98; 95% CI, 1.78-2.21) were associated with increased risk of dementia, as were midlife smoking (HR, 1.41; 95% CI, 1.23-1.61), diabetes (HR, 1.77; 95% CI, 1.53-2.04), prehypertension (HR, 1.31; 95% CI, 1.14-1.51), and hypertension (HR, 1.39; 95% CI, 1.22-1.59). The HR for dementia for diabetes was almost as high as that for APOE ε4 genotype.

Conclusions and Relevance

Midlife vascular risk factors are associated with increased risk of dementia in black and white ARIC Study participants. Further studies are needed to evaluate the mechanism of and opportunities for prevention of the cognitive sequelae of these risk factors in midlife.

Olfaction and risk of dementia in a biracial cohort of older adults

OBJECTIVE

Prior studies indicate that olfactory function may be an early marker for cognitive impairment, but the body of evidence has been largely restricted to white populations.

METHODS

We studied 2,428 community-dwelling black and white older adults (baseline age 70-79 years) without dementia enrolled in the Health, Aging, and Body Composition (Health ABC) study. Olfaction was measured as odor identification (OI) with the 12-item Cross Cultural Smell Identification Test in year 3. We defined incident dementia over 12 years on the basis of hospitalization records, prescription for dementia medication, or 1.5-SD decline in race-stratified global cognition score. We assessed dementia risk associated with OI score (by tertile) using Cox proportional hazards models. All analyses were stratified by race.

RESULTS

Poorer OI in older adults without dementia was associated with increased risk of dementia. After adjustment for demographics, medical comorbidities, and lifestyle characteristics, white participants in the poor or moderate OI tertile had greater risk of dementia (adjusted hazard ratio [HR] 3.34, 95% confidence interval [CI] 2.45-4.54; and HR 1.84, 95% CI 1.33-2.54, respectively) compared to those in the good tertile of function. Among blacks, worse OI was associated with an increased risk of dementia, but the magnitude of the effect was weaker (p for interaction = 0.04) for the poor OI tertile (adjusted HR 2.03, 95% CI 1.44-2.84) and for the moderate tertile (adjusted HR 1.42, 95% CI 0.97-2.10). There was no interaction between OI and APOE ε4 and risk of dementia.

CONCLUSIONS

While the magnitude of the association was stronger in whites, we found that poor OI was associated with increased risk of dementia among both black and white older adults.

The ARIC-PET amyloid imaging study: Brain amyloid differences by age, race, sex, and APOE

OBJECTIVE

To evaluate differences in amyloid deposition in a community-based cohort without dementia by age, sex, race, education, and APOE ε4 allele status.

METHODS

Recruited from the longitudinal Atherosclerosis Risk in Communities study, 329 participants without dementia, ages 67-88 years, were imaged using florbetapir PET at 3 US community sites (Washington County, Maryland; Forsyth County, North Carolina; and Jackson, Mississippi). Standardized uptake value ratios (SUVRs) were calculated; global cortical SUVR >1.2 was evaluated as the primary outcome. Age, race, sex, education level, and number of APOE ε4 alleles were evaluated in multivariable models including vascular risk factors, brain white matter hyperintensity and total intracranial volume, and cognitive status.

RESULTS

A total of 141 of the participants (43%) were black. In multivariable models, odds of elevated SUVR was increased in participants with increasing age (odds ratio [OR] 1.63, 95% confidence interval [CI] 1.01-2.65 per 10 years of age) and black race (OR 2.08, 95% CI 1.23-3.51) but did not differ by educational level. Each ε4 allele was associated with increased odds of elevated SUVR (OR 2.65, 95% CI 1.61-4.39).

CONCLUSIONS

In this community-based cohort without dementia, florbetapir uptake is associated with older age and APOE genotype. Black race was associated with higher SUVR, after adjusting for demographics, vascular risk factors, cognitive status, white matter hyperintensity volume, and APOE genotype, with effect sizes nearing those seen for APOE ε4. Replication of these findings is needed in other cohorts, and reasons for and consequences of these observed differences by race warrant further study.