Race/Ethnic Disparities in Mild Cognitive Impairment and Dementia: The Northern Manhattan Study

BACKGROUND

Variability in dementia rates across racial and ethnic groups has been estimated at 60%. Studies suggest disparities in Caribbean Hispanic and Black populations, but community-based data are limited.

OBJECTIVE

Estimate the prevalence of mild cognitive impairment (MCI) and dementia in the racially and ethnically diverse community-based Northern Manhattan Study cohort and examine sociodemographic, vascular risk factor, and brain imaging correlates.

METHODS

Cases of MCI and dementia were adjudicated by a team of neuropsychologists and neurologists and prevalence was estimated across race/ethnic groups. Ordinal proportional odds models were used to estimate race/ethnic differences in the prevalence of MCI or dementia adjusting for sociodemographic variables (model 1), model 1 plus potentially modifiable vascular risk factors (model 2), and model 1 plus structural imaging markers of brain integrity (model 3).

RESULTS

There were 989 participants with cognitive outcome determinations (mean age 69±9 years; 68% Hispanic, 16% Black, 14% White; 62% women; mean (±SD) follow-up five (±0.6) years). Hispanic and Black participants had greater likelihood of MCI (20%) and dementia (5%) than White participants accounting for age and education differences. Hispanic participants had greater odds of MCI or dementia than both White and Black participants adjusting for sociodemographic variables, vascular risk factors, and brain imaging factors. White matter hyperintensity burden was significantly associated with greater odds of MCI or dementia (OR = 1.3, 1.1 to 1.6), but there was no significant interaction by race/ethnicity.

CONCLUSION

In this diverse community-based cohort, cross-sectional data revealed significant race/ethnic disparities in the prevalence of MCI and dementia. Longer follow-up and incidence data are needed to further clarify these relationships.

Association Between Intracerebral Hemorrhage and Subsequent Arterial Ischemic Events in Participants From 4 Population-Based Cohort Studies

Importance

Intracerebral hemorrhage and arterial ischemic disease share risk factors, to our knowledge, but the association between the 2 conditions remains unknown.

Objective

To evaluate whether intracerebral hemorrhage was associated with an increased risk of incident ischemic stroke and myocardial infarction.

Design, Setting, and Participants

An analysis was conducted of pooled longitudinal participant-level data from 4 population-based cohort studies in the United States: the Atherosclerosis Risk in Communities (ARIC) study, the Cardiovascular Health Study (CHS), the Northern Manhattan Study (NOMAS), and the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study. Patients were enrolled from 1987 to 2007, and the last available follow-up was December 31, 2018. Data were analyzed from September 1, 2019, to March 31, 2020.

Exposure

Intracerebral hemorrhage, as assessed by an adjudication committee based on predefined clinical and radiologic criteria.

Main Outcomes and Measures

The primary outcome was an arterial ischemic event, defined as a composite of ischemic stroke or myocardial infarction, centrally adjudicated within each study. Secondary outcomes were ischemic stroke and myocardial infarction. Participants with prevalent intracerebral hemorrhage, ischemic stroke, or myocardial infarction at their baseline study visit were excluded. Cox proportional hazards regression was used to examine the association between intracerebral hemorrhage and subsequent arterial ischemic events after adjustment for baseline age, sex, race/ethnicity, vascular comorbidities, and antithrombotic medications.

Results

Of 55 131 participants, 47 866 (27 639 women [57.7%]; mean [SD] age, 62.2 [10.2] years) were eligible for analysis. During a median follow-up of 12.7 years (interquartile range, 7.7-19.5 years), there were 318 intracerebral hemorrhages and 7648 arterial ischemic events. The incidence of an arterial ischemic event was 3.6 events per 100 person-years (95% CI, 2.7-5.0 events per 100 person-years) after intracerebral hemorrhage vs 1.1 events per 100 person-years (95% CI, 1.1-1.2 events per 100 person-years) among those without intracerebral hemorrhage. In adjusted models, intracerebral hemorrhage was associated with arterial ischemic events (hazard ratio [HR], 2.3; 95% CI, 1.7-3.1), ischemic stroke (HR, 3.1; 95% CI, 2.1-4.5), and myocardial infarction (HR, 1.9; 95% CI, 1.2-2.9). In sensitivity analyses, intracerebral hemorrhage was associated with arterial ischemic events when updating covariates in a time-varying manner (HR, 2.2; 95% CI, 1.6-3.0); when using incidence density matching (odds ratio, 2.3; 95% CI, 1.3-4.2); when including participants with prevalent intracerebral hemorrhage, ischemic stroke, or myocardial infarction (HR, 2.2; 95% CI, 1.6-2.9); and when using death as a competing risk (subdistribution HR, 1.6; 95% CI, 1.1-2.1).

Conclusions and Relevance

This study found that intracerebral hemorrhage was associated with an increased risk of ischemic stroke and myocardial infarction. These findings suggest that intracerebral hemorrhage may be a novel risk marker for arterial ischemic events.

Telehealth After Stroke Care Pilot Randomized Trial of Home Blood Pressure Telemonitoring in an Underserved Setting

BACKGROUND

Hypertension is the most important modifiable stroke risk factor, but blood pressure (BP) remains poorly controlled after stroke, especially among Black and Hispanic patients. We tested the feasibility of TASC (Telehealth After Stroke Care), a post-acute stroke care model integrating nurse-supported home BP telemonitoring, tailored infographics, and multidisciplinary team video visits.

METHODS

Acute stroke patients with hypertension were randomized at discharge to usual care or usual care with TASC. Usual care patients received video visits with primary care and stroke. TASC included a tablet and monitor to wirelessly transmit BP data to the electronic health record, with telenursing support, tailored infographics to explain BP readings, and pharmacist visits. Outcomes assessment was blinded. Feasibility outcomes included recruitment, randomization, adherence, and retention. Systolic BP from baseline to 3 months after discharge was evaluated using generalized linear modeling.

RESULTS

Fifty patients (64±14 years; 36% women' 44% Hispanic, 32% Black, 54% ≤high school education, 30% private insurance), and 75% of all eligible were enrolled over 6.3 months. Baseline systolic BP was similar in both (TASC n=25, 140±19 mm Hg; usual care n=25, 142±19 mm Hg). At 3 months, adherence to video visits (91% versus 75%, P=0.14) and retention (84% versus 64%, P=0.11) were higher with TASC. Home systolic BP declined by 16±19 mm Hg from baseline in TASC and increased by 3±24 mm Hg in usual care (P=0.01). Among Black patients, systolic BP control (<130 mm Hg) improved from 40% to 100% with TASC versus 14% to 29%, and among Hispanic patients, from 23% to 62% with TASC, versus 33% to 17% in usual care.

CONCLUSIONS

Enhancing post-acute stroke care with home BP telemonitoring is feasible to improve hypertension in an underserved setting and should be tested in a definitive randomized clinical trial.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04640519.

APOE ϵ4 modifies the relationship between infectious burden and poor cognition

OBJECTIVE

We investigated whether APOE ϵ4 is an effect modifier of the association between infectious burden (IB) and poor cognition in a multiethnic cohort, the Northern Manhattan Study.

METHODS

IB was assessed by a quantitative weighted index of exposure to common pathogens associated with vascular risk, infectious burden index (IBI), and by serology for individual infections. Cognition was assessed by completion of the Mini-Mental State Examination at baseline and a full neuropsychological test battery after a median follow-up of approximately 6 years. Adjusted linear and logistic regressions estimated the association between IBI and cognition, with a term included for the interaction between APOE ϵ4 and IBI.

RESULTS

Among those with full neuropsychological test results (n = 569), there were interactions between IBI and APOE ϵ4 (p = 0.07) and herpes simplex virus 1 (HSV-1) and APOE ϵ4 (p = 0.02) for processing speed. IBI was associated with slower processing speed among non-ϵ4 carriers (β = -0.08 per SD change in IBI, 95% confidence interval [CI] -0.16 to -0.01), but not among APOE ϵ4 carriers (β = 0.06 per SD change in IBI, 95% CI -0.08 to 0.19). HSV-1 positivity was associated with slower processing speed among non-ϵ4 carriers (β = -0.24, 95% CI -0.45 to -0.03), but not among APOE ϵ4 carriers (β = 0.27, 95% CI -0.09 to 0.64).

CONCLUSIONS

Potential effect modification by the APOE ϵ4 allele on the relationship of infection, and particularly viral infection, to cognitive processing speed warrants further investigation.

TASC (Telehealth After Stroke Care): a study protocol for a randomized controlled feasibility trial of telehealth-enabled multidisciplinary stroke care in an underserved urban setting

Background

Hypertension is the most important modifiable risk factor for recurrent stroke, and blood pressure (BP) reduction is associated with decreased risk of stroke recurrence. However, hypertension remains poorly controlled in many stroke survivors. Black and Hispanic patients have a higher prevalence of uncontrolled BP and higher rates of stroke. Limited access to care contributes to challenges in post-stroke care. Telehealth After Stroke Care (TASC) is a telehealth intervention that integrates remote BP monitoring (RBPM) including nursing telephone support, tailored BP infographics and telehealth video visits with a multidisciplinary team approach including pharmacy to improve post-stroke care and reduce stroke disparities.

Methods

In this pilot trial, 50 acute stroke patients with hypertension will be screened for inclusion prior to hospital discharge and randomized to usual care or TASC. Usual care patients will be seen by a primary care nurse practitioner at 1–2 weeks and a stroke neurologist at 1 and 3 months. In addition to these usual care visits, TASC intervention patients will see a pharmacist at 4 and 8 weeks and will be enrolled in RBPM consisting of home BP monitoring with interval calls by a centralized team of telehealth nurses. As part of RBPM, TASC patients will be provided with a home BP monitoring device and electronic tablet that wirelessly transmits home BP data to the electronic health record. They will also receive tailored BP infographics that help explain their BP readings. The primary outcome will be feasibility including recruitment, adherence to at least one video visit and retention rates. The clinical outcome for consideration in a subsequent trial will be within-patient change in BP from baseline to 3 months after discharge. Secondary outcomes will be medication adherence self-efficacy and satisfaction with post-stroke telehealth, both measured at 3 months. Additional patient reported outcomes will include depression, cognitive function, and socioeconomic determinants. Multidisciplinary team competency and fidelity measures will also be assessed.

Conclusions

Integrated team-based interventions may improve BP control and reduce racial/ethnic disparities in post-stroke care. TASC is a post-acute stroke care model that is novel in providing RBPM with tailored infographics, and a multidisciplinary team approach including pharmacy. Our pilot will determine if such an approach is feasible and effective in enhancing post-stroke BP control and promoting self-efficacy.

Trial registration

ClinicalTrials.gov NCT04640519

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-022-01025-z.

Racial/ethnic differences in the association of incident stroke with late onset epilepsy: The Northern Manhattan Study

OBJECTIVE

Little is known about the incidence of late onset epilepsy (LOE) across different racial/ethnic groups in the USA, particularly in the Hispanic population. Stroke, a strong predictor of LOE, is more common in non-Hispanic Blacks (NHBs) and Hispanics than in non-Hispanic Whites (NHWs). We assessed the incidence of LOE across racial/ethnic groups and examined whether the associations of stroke with LOE risk differ by race/ethnicity.

METHODS

The Northern Manhattan Study is a population-based longitudinal study of older adults enrolled between 1993 and 2001. Participants free of history of stroke or epilepsy at baseline (n = 3419) were followed prospectively for incidence of LOE. We estimated LOE incidence per 1000 person-years in each racial/ethnic group. We used Cox proportional hazards regression to assess the association of race/ethnicity with LOE and multiplicative interactions of race/ethnicity with incident stroke in relation to LOE, adjusting for demographics and comorbid diagnoses.

RESULTS

During 51 176 person-years of follow-up, 183 individuals developed LOE. Incidence of LOE was significantly higher in NHBs (6.2 per 1000 person-years) than in NHWs (3.3 per 1000 person-years, p = .004). There was no significant difference in LOE incidence between NHWs (3.3 per 1000 person-years) and Hispanics (2.6 per 1000 person-years, p = .875). However, following incident stroke, the risk of LOE differed across racial/ethnic groups. Incident stroke was associated with 2.55 times the risk of LOE among NHWs (95% confidence interval [CI] = .88-7.35), 8.53 times the risk of LOE among Hispanics (95% CI = 5.36-13.57, p = .04 for stronger association than that in NHWs), and 6.46 times the risk of LOE among NHBs (95% CI = 3.79-11.01, p = .12 for stronger association than that in NHWs).

SIGNIFICANCE

We found a stronger association of incident stroke with LOE risk in Hispanics and NHBs than in NHWs, offering some insight into the racial/ethnic disparities of LOE incidence.

Relationships of hematocrit concentration with dementia from a multiethnic population-based study

Objective

Red blood cell (RBC) concentration impacts cerebrovascular disease, yet it is unclear whether RBC concentrations relate to dementia risk, particularly in racially/ethnically diverse cohorts. We investigated whether RBC concentrations associate with incident dementia risk in a diverse population of stroke-free individuals and explored whether cerebral small vessel disease (CSVD) mediates this relationship.

Methods

A longitudinal observational analysis was performed using a population-based cohort of stroke-free, older adult participants (>50 years) from the Northern Manhattan Study (NOMAS) enrolled between 2003 and 2008. Participants received baseline hematocrit testing, MRI neuroimaging, and cognitive assessments at baseline and long-term follow-up. Associations of baseline hematocrit as a categorical variable (low, normal [reference], and high based on laboratory reference levels) with incident dementia were assessed using Cox models adjusting for relevant covariates. Separate analyses investigated whether MRI CSVD mediated these relationships.

Results

We studied 1,207 NOMAS participants (mean age 71 ± 9 years, 60% female, 66% Hispanic). Mean hematocrit was 41.2% (±3.8) with 16% of participants developing incident dementia. Lower hematocrit associated with increased dementia risk (adjusted hazard ratio 1.81 [1.01-3.23]) after adjusting for age, sex, race/ethnicity, education, APOE status, and comorbidities. High hematocrit was not associated with dementia risk. No interactions by sex or race/ethnicity were seen and baseline CSVD did not mediate relationships between hematocrit and dementia.

Conclusion

Low hematocrit associated with dementia risk in our diverse population cohort. However, our study limitations in laboratory and neuroimaging timing in addition to clarifying mechanistic underpinnings for our observations necessitates further work to clarify whether anemia can serve as a trackable, preventable/treatable risk factor for dementia.

Abstract 108: Home Blood Pressure Telemonitoring-enhanced Versus Usual Post-acute Stroke Care In An Underserved Setting: The Telehealth After Stroke Care Pilot Randomized Clinical Trial

Introduction: Hypertension is the most important modifiable risk factor for recurrent stroke. However, it remains poorly controlled after stroke, especially among Black and Hispanic patients. Black and Hispanics have a higher prevalence of uncontrolled BP and limited access to care. Interventions that promote equitable access are needed to improve outcomes.

Aim: We tested whether a randomized trial of post-acute stroke care that integrates nurse-supported home BP telemonitoring, tailored infographics, and video visits with a multidisciplinary team including pharmacy (Telehealth After Stroke Care (TASC intervention) was feasible.

Methods: Acute stroke patients with hypertension were randomized prior to discharge to usual care or TASC. Usual care patients received a video visit with primary care at 1-2 weeks and stroke specialist at 6 and 12 weeks after discharge. TASC patients received a tablet that wirelessly transmits BP data to the electronic health record, supported by remote telehealth nurse monitoring along with BP infographics, developed through community participatory design, at first visit and pharmacist visits. Outcomes included recruitment feasibility, visit adherence, and retention. Generalized linear modeling was used to evaluate within-patient home BP change.

Results: Of 67 eligible patients, 6 were discharged before recruitment, 8 refused and 3 engaged in other studies. Fifty enrolled patients included 44% Hispanic, 32% Black and 36% women with mean age 64.3 (±14.0) yrs. About half had ≤ a high school education and 30% had commercial insurance. Baseline SBP was similar in TASC (140 ± 19 mmHg) vs. usual care (142 ± 19 mmHg). Retention rate was higher in TASC vs. usual care (84% vs 64%, p=0.11). Adherence to video visits was also higher in TASC (91% vs 75%, p=0.14). SBP control was better in TASC (76% vs. 25%, p<0.01). At 12 weeks, home SBP declined by 16 ± 19 mmHg from baseline in TASC vs increased by 3 ± 24 mmHg (p<0.01) in usual care. SBP control in Black patients improved from 40% at baseline to 100% in TASC vs from 14% to 29% in usual care.

Conclusion: Enhancing post-acute stroke care with home BP telemonitoring is a promising approach to improving hypertension control in an underserved setting that should be tested in a definitive randomized trial.

Clinical Telepharmacy: Addressing Care Gaps in Diabetes Management for an Underserved Urban Population Using a Collaborative Care Model

Introduction: Optimal chronic care management is limited by low health care access and health literacy among underserved populations. We introduced clinical pharmacy services to enhance our patient-centered home model, which serves mostly Medicare/Medicaid-insured patients. Primary care providers (PCP) refer patients with uncontrolled diabetes to the pharmacist for chronic disease management between PCP appointments to bring A1c to goal under a collaborative agreement. This workflow existed before the COVID-19 pandemic and was primarily in-person visits. Our model transitioned to telehealth, where pharmacy services continued via audio/video visits to avoid disruption in care. Methods: A collaborative scope of practice within care guidelines was developed with PCPs. Established patients with uncontrolled diabetes were referred to the clinical pharmacist. The workflow remained consistent through January 1, 2019 to January 31, 2020 (pre-COVID), and April 1, 2020 to October 31, 2021 (post-COVID). February and March 2020 were excluded due to changing operational processes at the pandemic onset. The pharmacist independently saw patients for medication-related interventions and ordered associated labs within the scope of practice. The program was retrospectively evaluated via process metrics (visit volume and intervention types) and clinical outcome (A1c reduction). Results: A total of 105 patients were referred for diabetes management during the study period. These were in-person pre-COVID (95%) and shifted to entirely audio/video (100%) post-COVID. Impact of pharmacy services was sustained through the change in care model: an A1c reduction of more than 0.5% was observed in 65% (n = 20) and 69% (n = 49) of patients managed by the pharmacist, pre- and post-COVID, respectively. Pharmacy visit volumes were 86 versus 308, respectively. Conclusion: Pharmacy referral and visit volumes increased over the pandemic, made possible via telehealth. The goal attainment rate observed pre-COVID was amplified even with the growth in services over time. Clinical pharmacy services delivered through audio/video telehealth visits may be equally effective compared to face-to-face services.

Inequities in Telemedicine Use Among Patients With Stroke and Cerebrovascular Diseases

Background and Objectives

In response to the COVID-19 pandemic, outpatient stroke care delivery was rapidly transformed to outpatient evaluation through video (VTM) and telephone (TPH) telemedicine (TM) visits around the world. We sought to evaluate the sociodemographic differences in outpatient TM use among stroke patients.

Methods

We conducted a retrospective chart review of outpatients evaluated at 3 tertiary stroke centers in the early period of the pandemic, 3/16/2020 through 7/31/2020. We compared the use of TM by patient characteristics including age, sex, race/ethnicity, insurance status, stroke type, patient type, and site. The association between TM use and patient characteristics was measured using the relative risk (RR) from a modified Poisson regression, and site-specific effects were controlled using a multilevel analysis.

Results

A total of 2,024 visits were included from UTHealth (n = 878), MedStar Health (n = 269), and Columbia (n = 877). The median age was 64 [IQR 52–74] years, and 53% were female. Approximately half of the patients had private insurance, 36% had Medicare, and 15% had Medicaid. Two-thirds of the visits were established patients. TM accounted for 90% of total visits, and the use of TM over office visits was primarily associated with site, not patient characteristics. TM utilization was associated with Asian and other/unknown race. Among TM users, older age, Black race, Hispanic ethnicity, and Medicaid insurance were associated with lower VTM use. Black (aRR 0.88, 95% CI 0.86–0.91,p< 0.001) and Hispanic patients (aRR 0.92, 95% CI 0.87–0.98,p= 0.005) had approximately 10% lower VTM use, while Asian patients (aRR 0.98, 95% CI 0.89–1.07,p= 0.59) had similar VTM use compared with White patients. Patients with Medicaid were less likely to use VTM compared with those with private insurance (aRR 0.86, 95% CI 0.81–0.91,p< 0.001).

Discussion

In our diverse cohort across 3 centers, we found differences in TM visit type by race and insurance early during the COVID-19 pandemic. These findings suggest disparities in VTM access across different stroke populations. As VTM remains an integral part of outpatient neurology practice, steps to ensure equitable access are essential.

Assessing changes on large cerebral arteries in CADASIL: Preliminary insights from a case-control analysis

INTRODUCTION

Parent large brain arteries are intimately related to their offspring's small arteries. Whether the CADASIL phenotype is confined to small vessels is unclear, and the involvement of large arteries in CADASIL has not been systematically studied.

METHODS

We conducted a retrospective observational study with patients with CADASIL and randomly selected controls with acute lacunar stroke from the New York-Presbyterian Hospital/Columbia University Irving Medical Center Stroke Registry. We measured the diameters of both groups' basilar artery (BA) and intracranial internal carotid artery (ICA) on T2-weighted images. Z-scores of the arteries were calculated to derive a Brain Arterial Remodeling (BAR) score. We rated cervical ICA tortuosity as 0=no tortuosity, 1 = 45-90° deviation, and 2= >90°. Generalized linear models compared large artery characteristics, adjusting for demographics and clinical variables.

RESULTS

We matched 37 patients with CADASIL with 104 controls. Patients with CADASIL were less likely to be Hispanic/Latino (p < 0.001), hypertensive (p < 0.001), or current smokers (p = 0.02) but more likely to have a prior stroke (p < 0.001) than controls. In adjusted models, patients with CADASIL had larger BA diameters than controls (p = 0.002), but there were no differences in the right and left ICA diameters (p = 0.73, p = 0.88). There was a statistical trend for higher cervical ICA tortuosity in patients with CADASIL compared to controls (p = 0.08).

CONCLUSIONS

Traditionally considered a small-vessel disease, patients with CADASIL have larger BA diameters and possibly higher cervical ICA tortuosity than controls. Whether these changes are part of the NOTCH-3 mutation phenotype or influence the clinical course is uncertain but should be further investigated.

Improving Patient-Reported Outcomes in Stroke Care using Remote Blood Pressure Monitoring and Telehealth

BACKGROUND

Inequities in health care access leads to suboptimal medication adherence and blood pressure (BP) control. Informatics-based approaches may deliver equitable care and enhance self-management. Patient-reported outcomes (PROs) complement clinical measures to assess the impact of illness on patients' well-being in poststroke care.

OBJECTIVES

The aim of this study was to determine the feasibility of incorporating PROs into Telehealth After Stroke Care (TASC) and to explore the effect of this team-based remote BP monitoring program on psychological distress and quality of life in an underserved urban setting.

METHODS

Patients discharged home from a Comprehensive Stroke Center were randomized to TASC or usual care for 3 months. They were provided with a BP monitor and a tablet that wirelessly transmitted data to a cloud-based platform, which were integrated with the electronic health record. Participants who did not complete the tablet surveys were contacted via telephone or e-mail. We collected the Patient-Reported Outcomes Measurement Information System Managing Medications and Treatment (PROMIS-MMT), Patient Activation Measure (PAM), Neuro-QOL (Quality of Life in Neurological Disorders) Cognitive Function, Neuro-QOL Depression, and Patient Health Questionnaire-9 (PHQ-9). T-tests and linear regression were used to evaluate the differences in PRO change between the arms.

RESULTS

Of the 50 participants, two-thirds were Hispanic or non-Hispanic Black individuals. Mechanisms of PRO submission for the arms included tablet (62 vs. 47%), phone (24 vs. 37%), tablet with phone coaching (10 vs. 16%), and e-mail (4 vs. 0%). PHQ-9 depressive scores were nominally lower in TASC at 3 months compared with usual care (2.7 ± 3.6 vs. 4.0 ± 4.1; p = 0.06). No significant differences were observed in PROMIS-MMT, PAM, or Neuro-QoL measures.

CONCLUSION

Findings suggest the feasibility of collecting PROs through an interactive web-based platform. The team-based remote BP monitoring demonstrated a favorable impact on patients' well-being. Patients equipped with appropriate resources can engage in poststroke self-care to mitigate inequities in health outcomes.

Relationships of hematocrit concentration with dementia from a multiethnic population-based study

OBJECTIVE

Red blood cell (RBC) concentration impacts cerebrovascular disease, yet it is unclear whether RBC concentrations relate to dementia risk, particularly in racially/ethnically diverse cohorts. We investigated whether RBC concentrations associate with incident dementia risk in a diverse population of stroke-free individuals and explored whether cerebral small vessel disease (CSVD) mediates this relationship.

METHODS

A longitudinal observational analysis was performed using a population-based cohort of stroke-free, older adult participants (>50 years) from the Northern Manhattan Study (NOMAS) enrolled between 2003-2008. Participants received baseline hematocrit testing, MRI neuroimaging, and cognitive assessments at baseline and long-term follow-up. Associations of baseline hematocrit as a categorical variable (low, normal [reference], and high based on laboratory reference levels) with incident dementia were assessed using Cox models adjusting for relevant covariates. Separate analyses investigated whether MRI CSVD mediated these relationships.

RESULTS

We studied 1207 NOMAS participants (mean age 71±9 years, 60% female, 66% Hispanic). Mean hematocrit was 41.2% (±3.8) with 16% of participants developing incident dementia. Lower hematocrit associated with increased dementia risk (adjusted hazard ratio 1.81 [1.01-3.23]) after adjusting for age, sex, race/ethnicity, education, APOE status, and comorbidities. High hematocrit was not associated with dementia risk. No interactions by sex or race/ethnicity were seen and baseline CSVD did not mediate relationships between hematocrit and dementia.

CONCLUSIONS

Low hematocrit associated with dementia risk in our diverse population cohort. Further work is needed to assess mechanisms behind anemia's relationship with dementia to assess whether this can serve as a trackable, preventable/treatable risk factor for dementia.