Riding the merry-go-round of racial disparities in ADRD research.

INTRODUCTION: With the rapid expansion of the aging population, the burden of Alzheimer's disease related dementias (ADRD) is anticipated to increase in racialized and minoritized groups who are at disproportionately higher risk. To date, research emphasis has been on further characterizing the existence of racial disparities in ADRD through comparisons to groups racialized as White that are assumed to be normative. Much of the literature on this comparison insinuates that racialized and minoritized groups experience poorer outcomes due to genetics, culture, and/or health behaviors. METHODS: This perspective shines a light on a category of ADRD research that employs ahistorical methodological approaches to describe racial disparities in ADRD that puts us on a merry-go-round of research with no benefits to society. METHODS: This commentary provides historical context for the use of race in ADRD research and justification for the study of structural racism. The commentary concludes with recommendations to guide future research.

Neighborhood segregation and cognitive change: Multi-Ethnic Study of Atherosclerosis.

INTRODUCTION: We investigated associations between neighborhood racial/ethnic segregation and cognitive change. METHODS: We used data (n = 1712) from the Multi-Ethnic Study of Atherosclerosis. Racial/ethnic segregation was assessed using Getis-Ord (Gi*) z-scores based on American Community Survey Census tract data (higher Gi* = greater spatial clustering of participant's race/ethnicity). Global cognition and processing speed were assessed twice, 6 years apart. Adjusted multilevel linear regression tested associations between Gi* z-scores and cognition. Effect modification by race/ethnicity, income, education, neighborhood socioeconomic status, and neighborhood social support was tested. RESULTS: Participants were on average 67 years old; 43% were White, 11% Chinese, 29% African American/Black, 17% Hispanic; 40% had high neighborhood segregation (Gi* > 1.96). African American/Black participants with greater neighborhood segregation had greater processing speed decline in stratified analyses, but no interactions were significant. DISCUSSION: Segregation was associated with greater processing speed declines among African American/Black participants. Additional follow-ups and comprehensive cognitive batteries may further elucidate these findings. HIGHLIGHTS: A study of neighborhood racial/ethnic segregation and change in cognition. Study was based on a racially and geographically diverse, population-based cohort of older adults. Racial/ethnic segregation (clustering) was measured by the Getis-ord (Gi*) statistic. We saw faster processing speed decline among Black individuals in segregated neighborhoods.

The structural and social determinants of Alzheimer's disease related dementias.

INTRODUCTION: The projected growth of Alzheimer's disease (AD) and AD-related dementia (ADRD) cases by midcentury has expanded the research field and impelled new lines of inquiry into structural and social determinants of health (S/SDOH) as fundamental drivers of disparities in AD/ADRD. METHODS: In this review, we employ Bronfenbrenner's ecological systems theory as a framework to posit how S/SDOH impact AD/ADRD risk and outcomes. RESULTS: Bronfenbrenner defined the "macrosystem" as the realm of power (structural) systems that drive S/SDOH and that are the root cause of health disparities. These root causes have been discussed little to date in relation to AD/ADRD, and thus, macrosystem influences, such as racism, classism, sexism, and homophobia, are the emphasis in this paper. DISCUSSION: Under Bronfenbrenner's macrosystem framework, we highlight key quantitative and qualitative studies linking S/SDOH with AD/ADRD, identify scientific gaps in the literature, and propose guidance for future research. HIGHLIGHTS: Ecological systems theory links structural/social determinants to AD/ADRD. Structural/social determinants accrue and interact over the life course to impact AD/ADRD. Macrosystem is made up of societal norms, beliefs, values, and practices (e.g., laws). Most macro-level determinants have been understudied in the AD/ADRD literature.

Evaluating Racial/Ethnic Equity in Planning-Related U.S. Health Impact Assessments Involving Parks and Greenspaces: A Review.

Problem research strategy and findings: Health impact assessment (HIA) reports are used by government agencies, other organizations, and stakeholders to evaluate potential health effects of plans/policies/projects. HIAs have the potential to promote anti-racist practices. We developed and used the Tool for the Racial/Ethnic Equity Evaluation of Health Impact Assessments (TREE-HIA) to score 50 U.S. HIA reports on planning-related projects/plans involving parks and greenspaces (2005-2020). More recent and more comprehensive HIA reports addressed racial/ethnic equity to a greater degree (e.g., median TREE-HIA scores: -1.3 in 2009-2012, 4.0 in 2017-2020, where higher scores indicate greater racial/equity considerations). Overall, HIA reports addressed racial/ethnic equity to a lesser degree than expected given the principal tenet of equity guiding HIAs and urban planning alike (42% had negative TREE-HIA scores indicating inadequate racial/ethnic equity consideration). However, the limited number and types of HIAs included in this study may affect generalization to all HIAs. Takeaway for practice: HIAs incorporating racial/ethnic equity comprehensively throughout the HIA process will better enable urban planners, HIA practitioners, decision makers, and communities of color to work together to combat racist planning practices through the shared goals of addressing health disparities and equity. TREE-HIA provides professionals and researchers with a brief tool that can be used/adapted to guide and evaluate future HIAs for racial/ethnic equity considerations.

Cognitive trajectory in mild cognitive impairment due to primary age-related tauopathy.

Primary age-related tauopathy is increasingly recognized as a separate neuropathological entity different from Alzheimer's disease. Both share the neuropathological features of tau aggregates and neuronal loss in the temporal lobe, but primary age-related tauopathy lacks the requisite amyloid plaques central to Alzheimer's disease. While both have similar clinical presentations, individuals with symptomatic primary age-related tauopathy are commonly of more advanced ages with milder cognitive dysfunction. Direct comparison of the neuropsychological trajectories of primary age-related tauopathy and Alzheimer's disease has not been thoroughly evaluated and thus, our objective was to determine how cognitive decline differs longitudinally between these two conditions after the onset of clinical symptoms. Data were obtained from the National Alzheimer's Coordinating Center on participants with mild cognitive impairment at baseline and either no neuritic plaques (i.e. primary age-related tauopathy) or moderate to frequent neuritic plaques (i.e. Alzheimer neuropathological change) at subsequent autopsy. For patients with Alzheimer's disease and primary age-related tauopathy, we compared rates of decline in the sum of boxes score from the CDR® Dementia Staging Instrument and in five cognitive domains (episodic memory, attention/working memory, executive function, language/semantic memory, and global composite) using z-scores for neuropsychological tests that were calculated based on scores for participants with normal cognition. The differences in rates of change were tested using linear mixed-effects models accounting for clinical centre clustering and repeated measures by individual. Models were adjusted for sex, age, education, baseline test score, Braak stage, apolipoprotein ε4 (APOE ε4) carrier status, family history of cognitive impairment, and history of stroke, hypertension, or diabetes. We identified 578 participants with a global CDR of 0.5 (i.e. mild cognitive impairment) at baseline, 126 with primary age-related tauopathy and 452 with Alzheimer's disease. Examining the difference in rates of change in CDR sum of boxes and in all domain scores, participants with Alzheimer's disease had a significantly steeper decline after becoming clinically symptomatic than those with primary age-related tauopathy. This remained true after adjusting for covariates. The results of this analysis corroborate previous studies showing that primary age-related tauopathy has slower cognitive decline than Alzheimer's disease across multiple neuropsychological domains, thus adding to the understanding of the neuropsychological burden in primary age-related tauopathy. The study provides further evidence to support the hypothesis that primary age-related tauopathy has distinct neuropathological and clinical features compared to Alzheimer's disease.

Associations between neighborhood greenspace and brain imaging measures in non-demented older adults: the Cardiovascular Health Study.

PURPOSE: Greater neighborhood greenspace has been associated with brain health, including better cognition and lower odds of Alzheimer's disease in older adults. We investigated associations between neighborhood greenspace and brain-based magnetic resonance imaging (MRI) measures and potential effect modification by sex or apolipoprotein E genotype (APOE), a risk factor for Alzheimer's disease. METHODS: We obtained a sample of non-demented participants 65 years or older (n = 1125) from the longitudinal, population-based Cardiovascular Health Study (CHS). Greenspace data were derived from the National Land Cover Dataset. Adjusted multivariable linear regression estimated associations between neighborhood greenspace five years prior to the MRI and left and right hippocampal volume and 10-point grades of ventricular size and burden of white matter hyperintensity. Interaction terms tested effect modification by APOE genotype and sex. CHS data (1989-1999) were obtained/analyzed in 2020. RESULTS: Participants were on average 79 years old [standard deviation (SD) = 4], 58% were female, and 11% were non-white race. Mean neighborhood greenspace was 38% (SD = 28%). Greater proportion of greenspace in the neighborhood five years before MRI was borderline associated with lower ventricle grade (estimate: - 0.30; 95% confidence interval: - 0.61, 0.00). We observed no associations between greenspace and the other MRI outcome measures and no evidence of effect modification by APOE genotype and sex. CONCLUSION: This study suggests a possible association between greater greenspace and less ventricular enlargement, a measure reflecting global brain atrophy. If confirmed in other longitudinal cohort studies, interventions and policies to improve community greenspaces may help to maintain brain health in older age.

Clinical diagnoses among individuals with primary age-related tauopathy versus Alzheimer's neuropathology.

Primary age-related tauopathy (PART) is increasingly recognized as a pathologic entity distinct from Alzheimer's disease (AD). Given that the diagnosis of PART is an autopsy diagnosis, it is unclear how PART is perceived in clinical practice. Thus, we investigated the presumptive primary and contributing diagnoses in individuals who had cognitive impairment while alive and who met neuropathologic criteria for PART at autopsy. We also compared these clinical diagnoses for people with PART to those with AD neuropathology (ADNP). We used data on 1354 participants from the National Alzheimer's Coordinating Center, restricting to those with no neuritic plaques (PART) or moderate/frequent neuritic plaques (ADNP); clinical visit within two years of autopsy; and mild cognitive impairment (MCI) or dementia at last visit. To assess if PART participants were less likely to receive a clinical diagnosis of AD at their last visit prior to autopsy, we used logistic regression, controlling for age, sex, education, and APOE ε4 status. There were 161 PART individuals (n = 49 MCI; n = 112 dementia) and 1193 individuals with ADNP (n = 75 MCI; n = 1118 dementia). Primary clinical diagnosis of AD was more common in those with ADNP (MCI: 69%; demented: 86%) than PART (MCI: 57%; demented: 52%). In the adjusted analysis, primary and contributing clinical diagnoses of AD remained less likely in PART vs. ADNP participants with dementia (OR: 0.22, 95% CI: 0.13-0.38). This study suggests that clinicians recognize a distinction in the clinical presentation between PART and ADNP, diagnosing AD less frequently in those with PART. Nonetheless, clinical AD was diagnosed greater than 50% of the time in PART participants with MCI or dementia. Ante-mortem criteria for diagnosis of PART need to be established, as PART is a neuropathological entity that is distinct from AD and has its own clinical and cognitive outcomes.

Cholinesterase Inhibitors May Not Benefit Mild Cognitive Impairment and Mild Alzheimer Disease Dementia.

INTRODUCTION: We investigated whether cholinesterase inhibitors (ChEIs) benefit cognitive outcomes in mild cognitive impairment due to Alzheimer disease (MCI-AD) and in mild AD dementia (ADdem). METHODS: Data from 2242 individuals, clinically diagnosed with MCI-AD [Clinical Dementia Rating (CDR), 0 or 0.5] or with mild ADdem (CDR, 0.5 or 1), were available from the National Alzheimer's Coordinating Center's (NACC) Uniform Data Set (UDS). General linear mixed models were used to examine the annual change in the CDR Sum of Boxes (CDR-SB) and in neuropsychological performance. We compared slopes before and after ChEI initiation among ChEI users, and also compared the change in scores of ChEI users versus nonusers. RESULTS: Thirty-four percent of 944 MCI-AD and 72% of 1298 ADdem participants were ChEI users. Cognitive decline was greater after ChEI initiation in MCI-AD and ADdem groups (eg, MCI-AD, CDR-SB: 0.03 points/y before initiation; 0.61 points/y after initiation, P<0.0001). Both MCI-AD and ADdem groups had faster decline after ChEI initiation than nonusers (eg, MCI-AD, CDR-SB: 0.61 points/y, ChEI users; 0.24 points/y, nonusers, P<0.0001). DISCUSSION: This study suggests that ChEI use may not improve the cognitive course in MCI-AD and mild ADdem.

Perceived burden among caregivers of patients with frontotemporal degeneration in the United States.

BACKGROUND: Frontotemporal degeneration (FTD) dementia often begins before age 60 and predominantly presents as four subtypes with prominent features of language, behavior, cognition, and motor symptoms. The early onset and unique symptoms place a distinct burden on caregivers of individuals with FTD versus other dementia types, such as Alzheimer's disease. This is the first known study to examine the domains of the FTD caregiver burden and the caregiver and patient characteristics associated with these domains. METHODS: In 2017, 674 FTD caregivers in the United States (US) completed a web-based survey of caregiver and patient demographics, disease severity/symptoms, caregiver burden, and financial costs of caregiving. The major factors of caregiver burden (Zarit Burden Inventory) were determined using a principal axis factor analysis with varimax rotation. Multiple linear regression analyses examined caregiver and patient characteristics associated with overall burden and three major factors of burden: role strain, personal strain, and performance strain. RESULTS: Increased neuropsychiatric symptoms was associated with overall caregiver burden and greater role, personal, and performance strain. Younger caregivers experienced greater overall burden and performance strain, female caregivers experienced increased role strain, and male caregivers experienced greater performance strain. Financial costs of caregiving and experiencing a caregiving crisis in the past year were associated with higher overall burden and role strain. CONCLUSIONS: This study suggests that the severity and sources of burden differ for caregivers of FTD patients versus patients with other dementia types. Differing predictors for each burden domain suggest targeted interventions to address the unique FTD caregiving challenges.

Failure to detect an association between self-reported traumatic brain injury and Alzheimer's disease neuropathology and dementia.

INTRODUCTION: Recent research with neuropathologic or biomarker evidence of Alzheimer's disease (AD) casts doubt on traumatic brain injury (TBI) as a risk factor for AD. We leveraged the National Alzheimer's Coordinating Center to examine the association between self-reported TBI with loss of consciousness and AD neuropathologic changes, and with baseline and longitudinal clinical status. METHODS: The sample included 4761 autopsy participants (453 with remote TBI with loss of consciousness; 2822 with AD neuropathologic changes) from National Alzheimer's Coordinating Center. RESULTS: Self-reported TBI did not predict AD neuropathologic changes (P > .10). Reported TBI was not associated with baseline or change in dementia severity or cognitive function in participants with or without autopsy-confirmed AD. DISCUSSION: Self-reported TBI with loss of consciousness may not be an independent risk factor for clinical or pathological AD. Research that evaluates number and severity of TBIs is needed to clarify the neuropathological links between TBI and dementia documented in other large clinical databases.

Polygenic hazard scores in preclinical Alzheimer disease.

Identifying asymptomatic older individuals at elevated risk for developing Alzheimer disease (AD) is of clinical importance. Among 1,081 asymptomatic older adults, a recently validated polygenic hazard score (PHS) significantly predicted time to AD dementia and steeper longitudinal cognitive decline, even after controlling for APOE ɛ4 carrier status. Older individuals in the highest PHS percentiles showed the highest AD incidence rates. PHS predicted longitudinal clinical decline among older individuals with moderate to high Consortium to Establish a Registry for Alzheimer's Disease (amyloid) and Braak (tau) scores at autopsy, even among APOE ɛ4 noncarriers. Beyond APOE, PHS may help identify asymptomatic individuals at highest risk for developing Alzheimer neurodegeneration. Ann Neurol 2017;82:484-488.

Factors Influencing Successful Lumbar Puncture in Alzheimer Research.

OBJECTIVE: Lumbar puncture (LP) is increasingly common in Alzheimer disease research; however, agreement to undergo LP varies. We sought to determine factors influencing LP consent at Alzheimer's Disease Centers (ADCs) in the United States. METHODS: A 3-part survey was distributed to each ADC: (1) ADC LP Experience; (2) LP Requestor Experience; and (3) Patient LP Experience (both Initial and Follow-up). In all, 64 LP Requestor, 579 Patient/Initial, and 404 Patient/Follow-up surveys were collected. Logistic regression analyses with generalized estimating equations were used to assess factors associated with LP agreement and post-LP complications. RESULTS: Asians and those viewing LP negatively were less likely to agree to LP. Three hundred fifty-two participants had an LP; LP headache occurred in 11.9% (blood patch required in 1.4%) and 9.9% reported other complications. Younger individuals, women, those diagnosed with mild cognitive impairment, use of a Quincke needle, ≤20 mL cerebrospinal fluid drawn, and hemorrhage during LP were associated with LP headache. Use of gravity flow during LP was associated with fewer other complications (nausea, dizziness, vasovagal response, back pain, neck stiffness, and/or nerve root pain). CONCLUSIONS: LP in Alzheimer disease research is generally safe and well tolerated. Factors influencing LP agreement potentially could be studied to advance participant acceptance of the procedure.

Results From the NACC Uniform Data Set Neuropsychological Battery Crosswalk Study.

INTRODUCTION: Four new nonproprietary tests were recommended for use in the National Alzheimer's Coordinating Center's Uniform Data Set Neuropsychological Battery. These tests are similar to previous tests but also allow for continuity of longitudinal data collection and wide dissemination among research collaborators. METHODS: A Crosswalk Study was conducted in early 2014 to assess the correlation between each set of new and previous tests. Tests with good correlation were equated using equipercentile equating. The resulting conversion tables allow scores on the new tests to be converted to equivalent scores on the previous tests. RESULTS: All pairs of tests had good correlation (ρ=0.68 to 0.78). Learning effects were detected for Logical Memory only. Confidence intervals were narrow at each point estimate, and prediction accuracy was high. DISCUSSION: The recommended new tests are well correlated with the previous tests. The equipercentile equating method produced conversion tables that provide a useful reference for clinicians and researchers.

Neuropathologic differences by race from the National Alzheimer's Coordinating Center.

INTRODUCTION: Compared to Caucasians, African Americans (AAs) have higher dementia prevalence, different genetic markers, and higher vascular risk factors. However, pathologic underpinnings are unknown. METHODS: We used neuropathologic and clinical data on 110 AA and 2500 Caucasians who were demented before death. The groups were compared regarding demographics, cognition, apolipoprotein E (APOE) genotype, comorbidities, and clinical and neuropathologic characteristics. RESULTS: AA and Caucasians differed in their demographics, cognition at the last visit before death, APOE genotype, presence of hypertension, primary clinical diagnoses, and AD, cerebrovascular disease (CVD), and other neuropathologies such as Lewy body disease (LBD). DISCUSSION: AD, LBD, and CVD pathology were more common and TDP and frontotemporal lobar degeneration-tau less common in AA than in Caucasians. APOE accounted for most of the AD neuropathologic differences. If replicated, the observed differences in underlying neuropathology by race will be important for public health policy and recruitment for and interpreting of clinical trials.

Body mass index, weight change, and clinical progression in mild cognitive impairment and Alzheimer disease.

The speed and severity of clinical progression after Alzheimer disease (AD) diagnosis varies and depends on multiple factors, most not well elucidated. We assessed whether body mass index (BMI) and 1-year weight change (WC) are associated with clinical progression in amnestic mild cognitive impairment (aMCI) and early-stage AD. Longitudinal data comprising 2268 aMCI and 1506 AD participants in the National Alzheimer's Coordinating Center's Uniform Data Set were used to examine nuances of clinical progression by BMI and WC, as well as potential variations in associations by age, sex, BMI (WC model), or apolipoprotein E genotype. In aMCI, high BMI (vs. moderate BMI) was associated with slower progression; weight loss (vs. no WC) was associated with faster progression. In AD, no significant differences were observed in clinical progression by BMI or WC. The association between BMI and clinical progression varied significantly by apolipoprotein E genotype in AD, and the association between WC and clinical progression varied significantly by sex and BMI in aMCI. Baseline BMI and 1-year WC in late life may serve as early prognostic indicators in aMCI and early-stage AD. If replicated, these results may help in counseling patients on anticipated clinical progression and suggest windows of opportunity for intervention.

Social Determinants of Health, Risk and Resilience against Alzheimer's Disease and Related Dementias: The Healthy Brain Initiative.

Background: Few studies have investigated associations between perceived social determinants of health (SDOH) and Alzheimer's disease and related dementia (ADRD) biomarkers or between SDOH and resilience against ADRD. Objective: To examine associations between perceived and objective SDOH and ADRD-related outcomes. Methods: We used cross-sectional data on≥50-year-olds without dementia in the Healthy Brain Initiative (n = 162). Questionnaires captured trust in neighbors and indices of perceived neighborhood greenspace access, time spent in neighborhood greenspaces, and interpersonal discrimination. Residential addresses were linked to 2021 Area Deprivation Index scores. The Vulnerability Index (VI) is based on 12 dementia risk factors (e.g., age, race/ethnicity, diabetes) and Resilience Index (RI) is based on 6 protective factors (e.g., diet, mindfulness, physical activity). Cognitive measured included number symbol coding task and Montreal Cognitive Assessment. Biomarkers included Aß42/40 and pTau-217/npTau-217, hippocampal and white matter hyperintensity volume, lipoprotein A, and high-sensitivity c-reactive protein. Results: Perceived greater access to greenspaces (estimate = 2.83, 95% CI = 1.40-4.26) and greater time in neighborhood greenspaces were associated with greater RI scores (estimate = 2.30, 95% CI = 1.24-3.35). Reporting greater discrimination (estimate = 0.10, 95% CI = 0.04-0.16) and living in higher deprivation neighborhoods were associated with greater VI scores (estimate = 0.017, 95% CI = 0.003-0.032). Greater discrimination was associated with greater white matter hyperintensity volume (estimate = 0.27, 95% CI = 0.04-0.51). Conclusions: Perceived greenspace access and time spent in greenspaces were associated with resilience against ADRD, and interpersonal discrimination was associated with vulnerability to ADRD. Future work needs to validate perceived SDOH measures, examine associations in racially/ethnic diverse populations, and investigate longitudinal associations between SDOH and ADRD-related biomarkers.

Spatial scale effects on associations between built environment and cognitive function: Multi-Ethnic Study of Atherosclerosis.

Built environments have the potential to favorably support cognitive function. Despite growing work on this topic, most of the work has ignored variation in the spatial scale of the effect. The issue with spatial scale effects is that the size and shape of the areal unit within which built environment characteristics are measured naturally influence the built environment exposure metric and thus the estimated associations with health. We used spatial distributed lag modeling (DLM) to estimate how associations between built environment exposures (walkable destinations [WD], social destinations [SD]) and change in cognition varied across distance of these destinations from participants' residences. Cognition was assessed as maintained/improved processing speed (PS) and global cognition (GC). Person-level data from Exam 5 (2010-2012) and Exam 6 (2016-2018) of the Multi-Ethnic Study of Atherosclerosis was used (N = 1380, mean age 67). Built environment data were derived from the National Establishment Time Series. Higher availability of walkable and social destinations at closer distance from participants' residence was associated with maintained/improved PS. The adjusted associations between maintained/improved PS and destinations waned with increasing distance from the residence; associations were evident until approximately 1.9-km for WD and 1.5-km for SD. Associations were most apparent for participants living in areas with high population density. We found little evidence for associations between change in GC and built environment at any distance. These results highlight the importance of identifying appropriate spatial scale to understand the mechanisms for built environment-cognition associations.

Systematic Review of Longitudinal Evidence and Methodologies for Research on Neighborhood Characteristics and Brain Health.

Objective: Synthesize longitudinal research evaluating neighborhood environments and cognition to identify methodological approaches, findings, and gaps. Methods: Included studies evaluated associations between neighborhood and cognition longitudinally among adults >45 years (or mean age of 65 years) living in developed nations. We extracted data on sample characteristics, exposures, outcomes, methods, overall findings, and assessment of disparities. Results: Forty studies met our inclusion criteria. Most (65%) measured exposure only once and a majority focused on green space and/or blue space (water), neighborhood socioeconomic status, and recreation/physical activity facilities. Similarly, over half studied incident impairment, cognitive function or decline (70%), with one examining MRI (2.5%) or Alzheimer's disease (7.5%). While most studies used repeated measures analysis to evaluate changes in the brain health outcome (51%), many studies did not account for any type of correlation within neighborhoods (35%). Less than half evaluated effect modification by race/ethnicity, socioeconomic status, and/or sex/gender. Evidence was mixed and dependent on exposure or outcome assessed. Conclusion: Although longitudinal research evaluating neighborhood and cognitive decline has expanded, gaps remain in types of exposures, outcomes, analytic approaches, and sample diversity.

Perceptions of greenspace and social determinants of health across the life course: The Life Course Sociodemographics and Neighborhood Questionnaire (LSNEQ).

We developed the Life Course Sociodemographics and Neighborhood Questionnaire (LSNEQ) to query older adults about perceived neighborhood greenspaces across the life course (i.e., distance to park, number of neighborhood parks/playgrounds, and neighborhood greenness) and about characteristics hypothesized to confound or moderate/mediate greenspace-health associations. Six perceived life course indices are derived from the LSNEQ: neighborhood socioeconomic status, neighborhood walking/biking, urbanicity, neighborhood amenities, neighborhood park access, and neighborhood greenness. Older adults from St. Louis, Missouri, and Sacramento, California, completed the LSNEQ in 2020-2021. The indices demonstrated borderline acceptable to good internal consistency (alpha = 0.60-0.79) and good to excellent test-retest reliability (ICC = 0.71-0.96) and detected different patterns of park access and neighborhood greenness by racialized group and location. Individuals with index scores indicating more neighborhood walking/biking and greater presence of neighborhood amenities over their life course were more likely to report neighborhood-based walking in older age. Overall, the LSNEQ is a reliable instrument to assess perceptions of life course social determinants of health including neighborhood greenspaces.

Diversity of Studies on Neighborhood Greenspace and Brain Health by Racialized/Ethnic Group and Geographic Region: A Rapid Review.

Studies examining associations between greenspace and Alzheimer's disease and related dementia (ADRD) outcomes are rapidly on the rise, yet no known literature reviews have summarized the racialized/ethnic group and geographic variation of those published studies. This is a significant gap given the known disparities in both greenspace access and ADRD risk between racialized/ethnic groups and between developed versus developing countries. In this rapid literature review, we (1) describe the diversity of published greenspace-brain health studies with respect to racialized/ethnic groups and geographic regions; (2) determine the extent to which published studies have investigated racialized/ethnic group differences in associations; and (3) review methodological issues surrounding studies of racialized/ethnic group disparities in greenspace and brain health associations. Of the 57 papers meeting our inclusion criteria as of 4 March 2022, 21% (n = 12) explicitly identified and included individuals who were Black, Hispanic/Latinx, and/or Asian. Twenty-one percent of studies (n = 12) were conducted in developing countries (e.g., China, Dominican Republic, Mexico), and 7% (n = 4) examined racialized/ethnic group differences in greenspace-brain health associations. None of the studies were framed by health disparities, social/structural determinants of health, or related frameworks, despite the known differences in both greenspace availability/quality and dementia risk by racialized/ethnic group and geography. Studies are needed in developing countries and that directly investigate racialized/ethnic group disparities in greenspace-brain health associations to target and promote health equity.