Brain health and shared risk factors for dementia and stroke

The Advanced BRain Imaging on ageing and Memory (ABRIM) data collection: Study design, data processing, and rationale

To understand the neurocognitive mechanisms that underlie heterogeneity in cognitive ageing, recent scientific efforts have led to a growing public availability of imaging cohort data. The Advanced BRain Imaging on ageing and Memory (ABRIM) project aims to add to these existing datasets by taking an adult lifespan approach to provide a cross-sectional, normative database with a particular focus on connectivity, myelinization and iron content of the brain in concurrence with cognitive functioning, mechanisms of reserve, and sleep-wake rhythms. ABRIM freely shares MRI and behavioural data from 295 participants between 18-80 years, stratified by age decade and sex (median age 52, IQR 36-66, 53.20% females). The ABRIM MRI collection consists of both the raw and pre-processed structural and functional MRI data to facilitate data usage among both expert and non-expert users. The ABRIM behavioural collection includes measures of cognitive functioning (i.e., global cognition, processing speed, executive functions, and memory), proxy measures of cognitive reserve (e.g., educational attainment, verbal intelligence, and occupational complexity), and various self-reported questionnaires (e.g., on depressive symptoms, pain, and the use of memory strategies in daily life and during a memory task). In a sub-sample (n = 120), we recorded sleep-wake rhythms using an actigraphy device (Actiwatch 2, Philips Respironics) for a period of 7 consecutive days. Here, we provide an in-depth description of our study protocol, pre-processing pipelines, and data availability. ABRIM provides a cross-sectional database on healthy participants throughout the adult lifespan, including numerous parameters relevant to improve our understanding of cognitive ageing. Therefore, ABRIM enables researchers to model the advanced imaging parameters and cognitive topologies as a function of age, identify the normal range of values of such parameters, and to further investigate the diverse mechanisms of reserve and resilience.

Identifying dementia from cognitive footprints in hospital records among Chinese older adults: a machine-learning study

Background

By combining theory-driven and data-driven methods, this study aimed to develop dementia predictive algorithms among Chinese older adults guided by the cognitive footprint theory.

Methods

Electronic medical records from the Clinical Data Analysis and Reporting System in Hong Kong were employed. We included patients with dementia diagnosed at 65+ between 2010 and 2018, and 1:1 matched dementia-free controls. We identified 51 features, comprising exposures to established modifiable factors and other factors before and after 65 years old. The performances of four machine learning models, including LASSO, Multilayer perceptron (MLP), XGBoost, and LightGBM, were compared with logistic regression models, for all patients and subgroups by age.

Findings

A total of 159,920 individuals (40.5% male; mean age [SD]: 83.97 [7.38]) were included. Compared with the model included established modifiable factors only (area under the curve [AUC] 0.689, 95% CI [0.684, 0.694]), the predictive accuracy substantially improved for models with all factors (0.774, [0.770, 0.778]). Machine learning and logistic regression models performed similarly, with AUC ranged between 0.773 (0.768, 0.777) for LASSO and 0.780 (0.776, 0.784) for MLP. Antipsychotics, education, antidepressants, head injury, and stroke were identified as the most important predictors in the total sample. Age-specific models identified different important features, with cardiovascular and infectious diseases becoming prominent in older ages.

Interpretation

The models showed satisfactory performances in identifying dementia. These algorithms can be used in clinical practice to assist decision making and allow timely interventions cost-effectively.

Funding

The Research Grants Council of Hong Kong under the Early Career Scheme 27110519.

Predicting post-stroke cognitive impairment using electronic health record data

BACKGROUND

Secondary prevention interventions to reduce post-stroke cognitive impairment (PSCI) can be aided by the early identification of high-risk individuals who would benefit from risk factor modification.

AIMS

To develop and evaluate a predictive model to identify patients at increased risk of PSCI over 5 years using data easily accessible from electronic health records.

METHODS

Cohort study that included primary care patients from two academic medical centers. Patients were aged 45 years or older, without prior stroke or prevalent cognitive impairment, with primary care visits and an incident ischemic stroke between 2003 and 2016 (development/internal validation cohort) or 2010 and 2022 (external validation cohort). Predictors of PSCI were ascertained from the electronic health record. The outcome was incident dementia/cognitive impairment within 5 years and beginning 3 months following stroke, ascertained using International Classification of Diseases, Ninth/Tenth Revision (ICD-9/10) codes. For model variable selection, we considered potential predictors of PSCI and constructed 400 bootstrap samples with two-thirds of the model derivation sample. We ran 10-fold cross-validated Cox proportional hazards models using a least absolute shrinkage and selection operator (LASSO) penalty. Variables selected in >25% of samples were included.

RESULTS

The analysis included 332 incident diagnoses of PSCI in the development cohort (n = 3741), and 161 and 128 incident diagnoses in the internal (n = 1925) and external (n = 2237) validation cohorts, respectively. The C-statistic for predicting PSCI was 0.731 (95% confidence interval (CI): 0.694-0.768) in the internal validation cohort, and 0.724 (95% CI: 0.681-0.766) in the external validation cohort. A risk score based on the beta coefficients of predictors from the development cohort stratified patients into low (0-7 points), intermediate (8-11 points), and high (12-23 points) risk groups. The hazard ratios (HRs) for incident PSCI were significantly different by risk categories in internal (high, HR: 6.2, 95% CI: 4.1-9.3; Intermediate, HR: 2.7, 95% CI: 1.8-4.1) and external (high, HR: 6.1, 95% CI: 3.9-9.6; Intermediate, HR: 2.8, 95% CI: 1.9-4.3) validation cohorts.

CONCLUSION

Five-year risk of PSCI can be accurately predicted using routinely collected data. Model output can be used to risk stratify and identify individuals at increased risk for PSCI for preventive efforts.

DATA ACCESS STATEMENT

Mass General Brigham data contain protected health information and cannot be shared publicly. The data processing scripts used to perform analyses will be made available to interested researchers upon reasonable request to the corresponding author.

Predicting post-stroke cognitive impairment using electronic health record data

Importance

Secondary prevention interventions to reduce post-stroke cognitive impairment (PSCI) can be aided by the early identification of high-risk individuals who would benefit from risk factor modification.

Objective

To develop and evaluate a predictive model to identify patients at increased risk of PSCI over 5 years using data easily accessible from electronic health records.

Design

Cohort study with patients enrolled between 2003-2016 with follow-up through 2022.

Setting

Primary care practices affiliated with two academic medical centers.

Participants

Individuals 45 years or older, without prior stroke or prevalent cognitive impairment, with primary care visits and an incident ischemic stroke between 2003-2016 (development/internal validation cohort) or 2010-2022 (external validation cohort).

Exposures

Predictors of PSCI were ascertained from the electronic health record.

Main Outcome

The outcome was incident dementia/cognitive impairment within 5 years and beginning 3 months following stroke, ascertained using ICD-9/10 codes. For model variable selection, we considered potential predictors of PSCI and constructed 400 bootstrap samples with two-thirds of the model derivation sample. We ran 10-fold cross-validated Cox proportional hazards models using a least absolute shrinkage and selection operator (LASSO) penalty. Variables selected in >25% of samples were included.

Results

The analysis included 332 incident diagnoses of PSCI in the development cohort (n=3,741), and 161 and 128 incident diagnoses in the internal (n=1,925) and external (n=2,237) validation cohorts. The c-statistic for predicting PSCI was 0.731 (95% CI: 0.694-0.768) in the internal validation cohort, and 0.724 (95% CI: 0.681-0.766) in the external validation cohort. A risk score based on the beta coefficients of predictors from the development cohort stratified patients into low (0-7 points), intermediate (8-11 points), and high (12-35 points) risk groups. The hazard ratios for incident PSCI were significantly different by risk categories in internal (High, HR: 6.2, 95% CI 4.1-9.3; Intermediate, HR 2.7, 95% CI: 1.8-4.1) and external (High, HR: 6.1, 95% CI: 3.9-9.6; Intermediate, HR 2.8, 95% CI: 1.9-4.3) validation cohorts.

Conclusions and Relevance

Five-year risk of PSCI can be accurately predicted using routinely collected data. Model output can be used to risk stratify and identify individuals at increased risk for PSCI for preventive efforts.

Associations of the Mediterranean-DASH Intervention for Neurodegenerative Delay diet with brain structural markers and their changes

INTRODUCTION

The associations of the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet with brain structural changes are unclear.

METHODS

Among 26,466 UK Biobank participants, a 15-point MIND score was calculated from 24-hour diet recalls from 2009 to 2012. We assessed its associations with 17 magnetic-resonance-derived brain volumetric markers and their longitudinal changes and explored whether genetic factors modify the associations.

RESULTS

Higher MIND adherence was associated with larger volumes of thalamus, putamen, pallidum, hippocampus, and accumbens (beta per 3-unit increment ranging from 0.024 to 0.033) and lower white matter hyperintensities (P-trends < 0.05), regardless of genetic predispositions of Alzheimer's disease. MIND score was not associated with their longitudinal changes (P > 0.05) over a median of 2.2 years among participants with repeated imaging assessments (N = 2963), but was associated with slower atrophy in putamen (beta: 0.026, P-trend = 0.044) and pallidum (beta: 0.030, P-trend = 0.033) among APOE ε4 non-carriers (N = 654).

DISCUSSION

The MIND diet showed beneficial associations with certain brain imaging markers, and its associations with long-term brain structural changes warrants future investigation.

HIGHLIGHTS

Adherence to the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet was significantly associated with higher volumes and larger gray matter volumes in certain brain regions in UK adults, and the associations were not modified by genetic factors. No significant associations were observed between MIND diet and longitudinal changes in the investigated brain structural markers over a median of 2.2 years. Higher MIND score was significantly associated with slower atrophy in the putamen and pallidum among APOE ε4 non-carriers.

Adaptation of the Concept of Brain Reserve for the Prediction of Stroke Outcome: Proxies, Neural Mechanisms, and Significance for Research

The prediction of stroke outcome is challenging due to the high inter-individual variability in stroke patients. We recently suggested the adaptation of the concept of brain reserve (BR) to improve the prediction of stroke outcome. This concept was initially developed alongside the one for the cognitive reserve for neurodegeneration and forms a valuable theoretical framework to capture high inter-individual variability in stroke patients. In the present work, we suggest and discuss (i) BR-proxies-quantitative brain characteristics at the time stroke occurs (e.g., brain volume, hippocampus volume), and (ii) proxies of brain pathology reducing BR (e.g., brain atrophy, severity of white matter hyperintensities), parameters easily available from a routine MRI examination that might improve the prediction of stroke outcome. Though the influence of these parameters on stroke outcome has been partly reported individually, their independent and combined impact is yet to be determined. Conceptually, BR is a continuous measure determining the amount of brain structure available to mitigate and compensate for stroke damage, thus reflecting individual differences in neural resources and a capacity to maintain performance and recover after stroke. We suggest that stroke outcome might be defined as an interaction between BR at the time stroke occurs and lesion load. BR in stroke can potentially be influenced, e.g., by modifying cardiovascular risk factors. In addition to the potential power of the BR concept in a mechanistic understanding of inter-individual variability in stroke outcome and establishing individualized therapeutic approaches, it might help to strengthen the synergy of preventive measures in stroke, neurodegeneration, and healthy aging.

Vascular Risk Factors and Brain Health in Aging: Insights from a Community-Based Cohort Study

Background

The aging population and high rates of Alzheimer's disease (AD) create significant medical burdens, prompting a need for early prevention. Targeting modifiable risk factors like vascular risk factors (VRFs), closely linked to AD, may provide a promising strategy for intervention.

Objective

This study investigates how VRFs influence cognitive performance and brain structures in a community-based cohort.

Methods

In this cross-sectional study, 4,667 participants over 50 years old, drawn from the Beijing Ageing Brain Rejuvenation Initiative project, were meticulously examined. Cognitive function and VRFs (diabetes mellitus, hypertension, hyperlipidemia, obesity, and smoking), were comprehensively assessed through one-to-one interviews. Additionally, a subset of participants (n = 719) underwent MRI, encompassing T1-weighted and diffusion-weighted scans, to elucidate gray matter volume and white matter structural network organization.

Results

The findings unveil diabetes as a potent detriment to memory, manifesting in atrophy within the right supramarginal gyrus and diminished nodal efficiency and degree centrality in the right inferior parietal lobe. Hypertension solely impaired memory without significant structural changes. Intriguingly, individuals with comorbid diabetes and hypertension exhibited the most pronounced deficits in both brain structure and cognitive performance. Remarkably, hyperlipidemia emerged as a factor associated with enhanced cognition, and preservation of brain structure.

Conclusions

This study illuminates the intricate associations between VRFs and the varied patterns of cognitive and brain structural damage. Notably, the synergistic effect of diabetes and hypertension emerges as particularly deleterious. These findings underscore the imperative to tailor interventions for patients with distinct VRF comorbidities, especially when addressing cognitive decline and structural brain changes.

Hybrid model of CT-fractional flow reserve, pericoronary fat attenuation index and radiomics for predicting the progression of WMH: a dual-center pilot study

Objective

To develop and validate a hybrid model incorporating CT-fractional flow reserve (CT-FFR), pericoronary fat attenuation index (pFAI), and radiomics signatures for predicting progression of white matter hyperintensity (WMH).

Methods

A total of 226 patients who received coronary computer tomography angiography (CCTA) and brain magnetic resonance imaging from two hospitals were divided into a training set (n = 116), an internal validation set (n = 30), and an external validation set (n = 80). Patients who experienced progression of WMH were identified from subsequent MRI results. We calculated CT-FFR and pFAI from CCTA images using semi-automated software, and segmented the pericoronary adipose tissue (PCAT) and myocardial ROI. A total of 1,073 features were extracted from each ROI, and were then refined by Elastic Net Regression. Firstly, different machine learning algorithms (Logistic Regression [LR], Support Vector Machine [SVM], Random Forest [RF], k-nearest neighbor [KNN] and eXtreme Gradient Gradient Boosting Machine [XGBoost]) were used to evaluate the effectiveness of radiomics signatures for predicting WMH progression. Then, the optimal machine learning algorithm was used to compare the predictive performance of individual and hybrid models based on independent risk factors of WMH progression. Receiver operating characteristic (ROC) curve analysis, calibration and decision curve analysis were used to evaluate predictive performance and clinical value of the different models.

Results

CT-FFR, pFAI, and radiomics signatures were independent predictors of WMH progression. Based on the machine learning algorithms, the PCAT signatures led to slightly better predictions than the myocardial signatures and showed the highest AUC value in the XGBoost algorithm for predicting WMH progression (AUC: 0.731 [95% CI: 0.603-0.838] vs.0.711 [95% CI: 0.584-0.822]). In addition, pFAI provided better predictions than CT-FFR (AUC: 0.762 [95% CI: 0.651-0.863] vs. 0.682 [95% CI: 0.547-0.799]). A hybrid model that combined CT-FFR, pFAI, and two radiomics signatures provided the best predictions of WMH progression [AUC: 0.893 (95%CI: 0.815-0.956)].

Conclusion

pFAI was more effective than CT-FFR, and PCAT signatures were more effective than myocardial signatures in predicting WMH progression. A hybrid model that combines pFAI, CT-FFR, and two radiomics signatures has potential use for identifying WMH progression.

Effect of blood pressure-lowering agents on microvascular function in people with small vessel diseases (TREAT-SVDs): a multicentre, open-label, randomised, crossover trial

BACKGROUND

Hypertension is the leading risk factor for cerebral small vessel disease. We aimed to determine whether antihypertensive drug classes differentially affect microvascular function in people with small vessel disease.

METHODS

We did a multicentre, open-label, randomised crossover trial with blinded endpoint assessment at five specialist centres in Europe. We included participants aged 18 years or older with symptomatic sporadic small vessel disease or cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and an indication for antihypertensive treatment. Participants were randomly assigned (1:1:1) to one of three sequences of antihypertensive treatment using a computer-generated multiblock randomisation, stratified by study site and patient group. A 2-week washout period was followed by three 4-week periods of oral monotherapy with amlodipine, losartan, or atenolol at approved doses. The primary endpoint was change in cerebrovascular reactivity (CVR) determined by blood oxygen level-dependent MRI response to hypercapnic challenge in normal-appearing white matter from the end of washout to the end of each treatment period. Efficacy analyses were done by intention-to-treat principles in all randomly assigned participants who had at least one valid assessment for the primary endpoint, and analyses were done separately for participants with sporadic small vessel disease and CADASIL. This trial is registered at ClinicalTrials.gov, NCT03082014, and EudraCT, 2016-002920-10, and is terminated.

FINDINGS

Between Feb 22, 2018, and April 28, 2022, 75 participants with sporadic small vessel disease (mean age 64·9 years [SD 9·9]) and 26 with CADASIL (53·1 years [7·0]) were enrolled and randomly assigned to treatment. 79 participants (62 with sporadic small vessel disease and 17 with CADASIL) entered the primary efficacy analysis. Change in CVR did not differ between study drugs in participants with sporadic small vessel disease (mean change in CVR 1·8 × 10-4%/mm Hg [SE 20·1; 95% CI -37·6 to 41·2] for amlodipine; 16·7 × 10-4%/mm Hg [20·0; -22·3 to 55·8] for losartan; -7·1 × 10-4%/mm Hg [19·6; -45·5 to 31·1] for atenolol; poverall=0·39) but did differ in patients with CADASIL (15·7 × 10-4%/mm Hg [SE 27·5; 95% CI -38·3 to 69·7] for amlodipine; 19·4 × 10-4%/mm Hg [27·9; -35·3 to 74·2] for losartan; -23·9 × 10-4%/mm Hg [27·5; -77·7 to 30·0] for atenolol; poverall=0·019). In patients with CADASIL, pairwise comparisons showed that CVR improved with amlodipine compared with atenolol (-39·6 × 10-4%/mm Hg [95% CI -72·5 to -6·6; p=0·019) and with losartan compared with atenolol (-43·3 × 10-4%/mm Hg [-74·3 to -12·3]; p=0·0061). No deaths occurred. Two serious adverse events were recorded, one while taking amlodipine (diarrhoea with dehydration) and one while taking atenolol (fall with fracture), neither of which was related to study drug intake.

INTERPRETATION

4 weeks of treatment with amlodipine, losartan, or atenolol did not differ in their effects on cerebrovascular reactivity in people with sporadic small vessel disease but did result in differential treatment effects in patients with CADASIL. Whether antihypertensive drug classes differentially affect clinical outcomes in people with small vessel diseases requires further research.

FUNDING

EU Horizon 2020 programme.

Association of Denture Use and Chewing Ability with Cognitive Function Analysed Using Panel Data from Korea Longitudinal Study of Aging (2006-2018)

This study aimed to investigate the association between denture use, chewing ability, and cognitive function in Korean middle-aged adults, using samples representing middle-aged people at the national level. This longitudinal study included 9998 middle-aged adults using the Korea Longitudinal Study of Aging 7th special survey data. Denture use, chewing ability, health-related factors, and general characteristics were assessed using the Computer-Assisted Personal Interview. After controlling for general characteristics using a generalized estimating equation model, the association of denture use and Mini-Mental State Examination (MMSE) scores with the chewing ability of those with or without dentures and MMSE scores were analysed. Among them, 24% of participants wore dentures, and 35.1% complained of difficulty chewing when wearing dentures. Among the participants who did not wear dentures, 16.4% complained of difficulty chewing. MMSE scores were lower among denture wearers than non-denture wearers (β = -0.026, p < 0.001). In both groups, MMSE scores decreased with chewing difficulty and were significantly reduced among non-denture wearers (p < 0.05). Chewing ability was closely associated with cognitive functioning. Therefore, in order to prevent cognitive decline, chewing discomfort while wearing dentures must be eliminated, and oral health must be maintained.

Liver Enzymes and the Risk of Stroke among the General Japanese Population: A Prospective Cohort Study

INTRODUCTION

Stroke is a major cause of morbidity and mortality. Liver enzymes, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transpeptidase (GGT), are markers of liver diseases with potential cardiovascular implications. This study aimed to investigate the prospective association between liver enzymes and stroke risk.

METHODS

We analyzed data from 3,379 men and 4,007 women without cardiovascular disease and registered in the Suita Study, a Japanese population-based prospective cohort study. The hazard ratios (HRs) and 95% confidence intervals (95% CIs) of stroke risk were estimated per quintiles of ALT, AST, and GGT in men and women.

RESULTS

Within a median follow-up period of 16.7 years, 438 incident stroke events were diagnosed. In men, compared to the second quintiles, the fifth (highest) quintiles of liver enzymes showed increased stroke risks: HRs (95% CIs) = 2.07 (1.35, 3.18) in ALT, 1.66 (1.10, 2.53) in AST, and 1.76 (1.11, 2.81) in GGT. The associations did not change with cerebral infarction risk: HRs (95% CIs) = 2.09 (1.24, 3.50) in ALT, 1.84 (1.11, 3.06) in AST, and 1.74 (1.00, 3.04) in GGT. The lowest ALT, AST, and GGT quintiles tended to show increased stroke and cerebral infarction risks, yet these associations were statistically insignificant. No such associations were shown in women.

CONCLUSION

Elevated ALT, AST, and GGT levels were associated with increased stroke and cerebral infarction risks among Japanese men.

Heart-brain connections: Phenotypic and genetic insights from magnetic resonance images

Cardiovascular health interacts with cognitive and mental health in complex ways, yet little is known about the phenotypic and genetic links of heart-brain systems. We quantified heart-brain connections using multiorgan magnetic resonance imaging (MRI) data from more than 40,000 subjects. Heart MRI traits displayed numerous association patterns with brain gray matter morphometry, white matter microstructure, and functional networks. We identified 80 associated genomic loci (P < 6.09 × 10-10) for heart MRI traits, which shared genetic influences with cardiovascular and brain diseases. Genetic correlations were observed between heart MRI traits and brain-related traits and disorders. Mendelian randomization suggests that heart conditions may causally contribute to brain disorders. Our results advance a multiorgan perspective on human health by revealing heart-brain connections and shared genetic influences.

Exploring what progress is being made in the development of health promotion material for vascular dementia: A systematic review of the evidence

A systematic review conducted by Price and Keady (Journal of Nursing and Healthcare of Chronic Illness, 2, 88 and 2010) demonstrated that there was a dearth of health-promoting literature available for people diagnosed with vascular dementia. The correlation between health behavior and the onset of cardiovascular change that can lead to vascular dementia had demonstrated a need for health education and health-promoting information to be made accessible to vulnerable populations to ameliorate the risk of cognitive decline because of cardiovascular disease. Dementia is a progressive and life-limiting condition and with limited treatment options and a lack of progress in identifying a way to delay onset or even cure the condition. Focus must be targeted towards risk reduction strategies that serve to reduce onset and decline and limit the global burden on not only the individual with the condition and their carers but also to the health and social care economy. To identify the progress that has been made in developing health-promoting literature and patient education guidance since 2010 a systematic literature review was undertaken. Using thematic analysis, CINAHL, MEDLINE, and psych INFO databases were accessed and following PRISMA guidelines an inclusion and exclusion criteria was developed in order to locate peer-reviewed articles. Titles and abstracts were reviewed to identify a match with key terms, and from 133 screened abstracts eight studies met the inclusion requirements. From the eight studies, thematic analysis was implemented to identify shared understanding of experiences relating to health promotion in vascular dementia. The methodology for the study was replicated from the authors' previous systematic review in 2010. Five key themes were identified in the literature (Healthy heart healthy brain; Risk factors; Risk reduction/modification; Interventions; Absence of targeted health promotion). From what little evidence was available to review the thematic analysis has demonstrated developments in knowledge into the link between the onset of cognitive impairment and vascular dementia because of compromised cardiovascular health. Modifying health behavior has become essential in ameliorating the risk of vascular cognitive decline. With these developments the synthesis of the literature demonstrates that even with these insights there continues to be a lack of targeted material that individuals can access to understand the link between cardiovascular health and cognitive decline. It is recognized that maximizing cardiovascular health has the potential to lessen the risk of vascular cognitive impairment and vascular dementia developing and progressing yet targeted health promoting material remains lacking. With the developments in understanding the causal links between poor cardiovascular health, vascular cognitive impairment, and vascular dementia progress now needs to be made in developing targeted health promotion material for individuals to access to share this knowledge to reduce the potential onset and subsequent burden of dementia.

Diagnosis and Management of Cerebral Small Vessel Disease

OBJECTIVE

Cerebral small vessel disease (CSVD) is a common neurologic condition that contributes to considerable mortality and disability because of its impact on ischemic and hemorrhagic stroke risk and dementia. While attributes of the disease have been recognized for over two centuries, gaps in knowledge remain related to its prevention and management. The purpose of this review is to provide an overview of the current state of knowledge for CSVD.

LATEST DEVELOPMENTS

CSVD can be recognized by well-defined radiographic criteria, but the pathogenic mechanism behind the disease is unclear. Hypertension control remains the best-known strategy for stroke prevention in patients with CSVD, and recent guidelines provide a long-term blood pressure target of less than 130/80 mm Hg for patients with ischemic and hemorrhagic stroke, including those with stroke related to CSVD. Cerebral amyloid angiopathy is the second leading cause of intracerebral hemorrhage and may be increasingly recognized because of newer, more sensitive imaging modalities. Transient focal neurologic episodes is a relatively new term used to describe "amyloid spells." Guidance on distinguishing these events from seizures and transient ischemic attacks has been published.

ESSENTIAL POINTS

CSVD is prevalent and will likely be encountered by all neurologists in clinical practice. It is important for neurologists to be able to recognize CSVD, both radiographically and clinically, and to counsel patients on the prevention of disease progression. Blood pressure control is especially relevant, and strategies are needed to improve blood pressure control for primary and secondary stroke prevention in patients with CSVD.

The EffecTs of Amlodipine and other Blood PREssure Lowering Agents on Microvascular FuncTion in Small Vessel Diseases (TREAT-SVDs) trial: Study protocol for a randomised crossover trial

Background

Hypertension is the leading modifiable risk factor for cerebral small vessel diseases (SVDs). Yet, it is unknown whether antihypertensive drug classes differentially affect microvascular function in SVDs.

Aims

To test whether amlodipine has a beneficial effect on microvascular function when compared to either losartan or atenolol, and whether losartan has a beneficial effect when compared to atenolol in patients with symptomatic SVDs.

Design

TREAT-SVDs is an investigator-led, prospective, open-label, randomised crossover trial with blinded endpoint assessment (PROBE design) conducted at five study sites across Europe. Patients aged 18 years or older with symptomatic SVD who have an indication for antihypertensive treatment and are suffering from either sporadic SVD and a history of lacunar stroke or vascular cognitive impairment (group A) or CADASIL (group B) are randomly allocated 1:1:1 to one of three sequences of antihypertensive treatment. Patients stop their regular antihypertensive medication for a 2-week run-in period followed by 4-week periods of monotherapy with amlodipine, losartan and atenolol in random order as open-label medication in standard dose.

Outcomes

The primary outcome measure is cerebrovascular reactivity (CVR) as determined by blood oxygen level dependent brain MRI signal response to hypercapnic challenge with change in CVR in normal appearing white matter as primary endpoint. Secondary outcome measures are mean systolic blood pressure (BP) and BP variability (BPv).

Discussion

TREAT-SVDs will provide insights into the effects of different antihypertensive drugs on CVR, BP, and BPv in patients with symptomatic sporadic and hereditary SVDs.

Funding

European Union's Horizon 2020 programme.

Trial registration

NCT03082014.

Longitudinal changes in cerebral blood flow and their relation with cognitive decline in patients with dementia: Current knowledge and future directions

The pathophysiology underlying cognitive decline is multifactorial, with increasing literature suggesting a role for cerebrovascular health. Cerebral blood flow (CBF) is an important element of cerebrovascular health, which raises questions regarding the relation between CBF and cognitive decline. Cross-sectional studies demonstrate lower CBF in patients with cognitive decline compared to healthy age-matched peers. Remarkably, longitudinal studies do not support a link between CBF reductions and cognitive decline. These studies, however, are often limited by small sample sizes and may therefore be underpowered to detect small effect sizes. Therefore, through a systematic review and meta-analysis of longitudinal studies, we examined whether longitudinal changes in global CBF are related to cognitive decline in subjects with Alzheimer's disease, and qualitatively described findings on regional CBF. Considering the growing impact of dementia and the lack of treatment options, it is important to understand the role of CBF as a prognostic biomarker and/or treatment target in dementia.

Mediterranean Diet on Sleep: A Health Alliance

The Mediterranean diet is a plant-based, antioxidant-rich, unsaturated fat dietary pattern that has been consistently associated with lower rates of noncommunicable diseases and total mortality, so that it is considered one of the healthiest dietary patterns. Clinical trials and mechanistic studies have demonstrated that the Mediterranean diet and its peculiar foods and nutrients exert beneficial effects against inflammation, oxidative stress, dysmetabolism, vascular dysfunction, adiposity, senescence, cognitive decline, neurodegeneration, and tumorigenesis, thus preventing age-associated chronic diseases and improving wellbeing and health. Nocturnal sleep is an essential physiological function, whose alteration is associated with health outcomes and chronic diseases. Scientific evidence suggests that diet and sleep are related in a bidirectional relationship, and the understanding of this association is important given their role in disease prevention. In this review, we surveyed the literature concerning the current state of evidence from epidemiological studies on the impact of the Mediterranean diet on nighttime sleep quantity and quality. The available studies indicate that greater adherence to the Mediterranean diet is associated with adequate sleep duration and with several indicators of better sleep quality. Potential mechanisms mediating the effect of the Mediterranean diet and its foods and nutrients on sleep are described, and gap-in-knowledge and new research agenda to corroborate findings are discussed.

Cerebral small vessel disease mediates the association between homocysteine and cognitive function

Objective

To investigate the relations of serum total homocysteine (tHcy) with cerebral small vessel disease (CSVD) and cognitive function and evaluate whether CSVD mediates the effect of serum tHcy on cognitive function.

Methods

A total of 1,033 consecutive eligible participants who received serum tHcy, brain magnetic resonance imaging (MRI), and neuropsychological assessment were included in this retrospective study. White matter hyperintensity, lacune, cerebral microbleed, and enlarged perivascular space were evaluated based on brain MRI. We used multivariate binary logistic regression analysis, multivariate ordinal logistic regression analysis, and mediation analyses to assess the relations of serum tHcy with CSVD and cognitive function.

Results

Serum tHcy levels were higher in patients with cognitive impairment than those with no cognitive impairment. Logistic regression analyses showed elevated serum tHcy was associated with cognitive impairment [odds ratio (OR): 10.475; 95% confidence interval (CI): 4.522 to 24.264; p < 0.001] and a higher CSVD burden score (OR: 17.151; 95% CI: 8.785 to 33.921; p < 0.001) after adjusting potential confounders. Compared with the lowest tHcy quartile, the multivariable-adjusted OR of the highest quartile was 4.851 (95% CI: 3.152 to 7.466; p for the trend < 0.001) for cognitive impairment, 3.862 (95% CI: 2.467 to 6.047; p for the trend < 0.001) for a severe CSVD burden score. Mediation analyses showed significant moderating effects (9.3–23.6%) by different imaging markers of CSVD on the association between higher serum tHcy levels and cognitive impairment.

Conclusion

Elevated serum tHcy is associated with cognitive impairment and the development of CSVD. A proportion of the association between elevated serum tHcy and cognitive impairment may be attributed to the presence of different imaging markers of CSVD, especially the severe CSVD burden score.

Racial Residential Segregation in Young Adulthood and Brain Integrity in Middle Age: Can We Learn From Small Samples?

Racial residential segregation is associated with multiple adverse health outcomes in Black individuals. Yet, the influence of structural racism and racial residential segregation on brain aging is less understood. In this study, we investigated the association between cumulative exposure to racial residential segregation over 25 years (1985-2010) in young adulthood, as measured by the Getis-Ord Gi* statistic, and year 25 measures of brain volume (cerebral, gray matter, white matter, and hippocampal volumes) in midlife. We studied 290 Black participants with available brain imaging data who were enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a prospective cohort study. CARDIA investigators originally recruited 2,637 Black participants aged 18-30 years from 4 field centers across the United States. We conducted analyses using marginal structural models, incorporating inverse probability of treatment weighting and inverse probability of censoring weighting. We found that compared with low/medium segregation, greater cumulative exposure to a high level of racial residential segregation throughout young adulthood was associated with smaller brain volumes in general (e.g., for cerebral volume, β = -0.08, 95% confidence interval: -0.15, -0.02) and with a more pronounced reduction in hippocampal volume, though results were not statistically significant. Our findings suggest that exposure to segregated neighborhoods may be associated with worse brain aging.

Intravenous Thrombolysis After First-Ever Ischemic Stroke and Reduced Incident Dementia Rate

BACKGROUND AND PURPOSE

The use of intravenous thrombolysis is associated with improved clinical outcomes. Whether thrombolysis is associated with reduced incidence of poststroke dementia remains uncertain. We sought to estimate if the use of thrombolysis following first-ever ischemic stroke was associated with a reduced rate of incident dementia using a pragmatic observational design.

METHODS

We included first-ever ischemic stroke patients from the Ontario Stroke Registry who had not previously been diagnosed with dementia. The primary outcome was incident dementia ascertained by a validated diagnostic algorithm. We employed inverse probability of treatment-weighted Cox proportional hazard models to estimate the cause-specific hazard ratio for the association of thrombolysis and incident dementia at 1 and 5 years following stroke.

RESULTS

From July 2003 to March 2013, 7072 patients with ischemic stroke were included, 3276 (46.3%) were female and mean age was 71.0 (SD, 12.8) years. Overall, 38.2% of the cohort (n=2705) received thrombolysis, 77.2% (n=2087) of which was administered within 3 hours of stroke onset. In the first year following stroke, thrombolysis administration was associated with a 24% relative reduction in the rate of developing dementia (cause-specific hazard ratio, 0.76 [95% CI, 0.58-0.97]). This association remained significant at 5 years (cause-specific hazard ratio, 0.79 [95% CI, 0.66-0.91]) and at the end of follow-up (median 6.3 years; cause-specific hazard ratio, 0.79 [95% CI, 0.68-0.89]).

CONCLUSIONS

Thrombolysis administration following first-ever ischemic stroke was independently associated with a reduced rate of dementia. Incident dementia should be considered as a relevant outcome when evaluating risk/benefit of thrombolysis in ischemic stroke patients.

Causal effect of insulin resistance on small vessel stroke and Alzheimer's disease: A Mendelian randomization analysis

BACKGROUND AND PURPOSE

The causal effect of insulin resistance on small vessel stroke and Alzheimer's disease (AD) was controversial in previous studies. We therefore applied Mendelian randomization (MR) analyses to identify the causal effect of insulin resistance on small vessel stroke and AD.

METHODS

We selected 12 single-nucleotide polymorphisms (SNPs) associated with fasting insulin levels and five SNPs associated with "gold standard" measures of insulin resistance as instrumental variables in MR analyses. Summary statistical data on SNP-small vessel stroke and on SNP-AD associations were derived from studies by the Multi-ancestry Genome-Wide Association Study of Stroke consortium (MEGASTROKE) and the Psychiatric Genomics Consortium-Alzheimer Disease Workgroup (PGC-ALZ) in individuals of European ancestry. Two-sample MR estimates were conducted with inverse-variance-weighted, robust inverse-variance-weighted, simple median, weighted median, weighted mode-based estimator, and MR pleiotropy residual sum and outlier (MR-PRESSO) methods.

RESULTS

Genetically predicted higher insulin resistance had a higher odds ratio (OR) of small vessel stroke (OR 1.23, 95% confidence interval [CI] 1.05-1.44, p = 0.01 using fasting insulin; OR 1.25, 95% CI 1.07-1.46, p = 0.006 using gold standard measures of insulin resistance) and AD (OR 1.13, 95% CI 1.04-1.23, p = 0.004 using fasting insulin; OR 1.02, 95% CI 1.00-1.03, p = 0.03 using gold standard measures of insulin resistance) using the inverse-variance-weighted method. No evidence of pleiotropy was found using MR-Egger regression.

CONCLUSION

Our findings provide genetic support for a potential causal effect of insulin resistance on small vessel stroke and AD.

Design of a randomised, double-blind, crossover, placebo-controlled trial of effects of sildenafil on cerebrovascular function in small vessel disease: Oxford haemodynamic adaptation to reduce pulsatility trial (OxHARP)

Background

Cerebral small vessel disease (SVD) is associated with increased cerebrovascular pulsatility, endothelial dysfunction, and impaired vascular reactivity. Vasodilating phosphodiesterase inhibitors may improve cardiovascular pulsatility and reactivity, and potentially reduce progression of SVD.

Hypothesis: Sildenafil, a PDE5 inhibitor, will reduce cerebrovascular pulsatility and increase cerebrovascular reactivity compared to placebo, and is non-inferior to cilostazol, a PDE3 inhibitor.

Methods

OxHARP is a randomised, double-blind, crossover trial of sildenafil 50 mg thrice daily, cilostazol 100 mg twice daily and placebo in 75 patients with mild to moderate small vessel disease and a previous lacunar or cryptogenic stroke or TIA. Participants undergo a physiological assessment at baseline and on each treatment, including transcranial Doppler ultrasound (TCD, DWL DopplerBox) to assess cerebrovascular pulsatility and reactivity to 4–6% carbon dioxide. In up to 60 patients, cerebrovascular pulsatility, perfusion and reactivity will also be assessed by MRI.

Outcome measures

The primary outcome is difference in middle cerebral artery pulsatility (Gosling’s Pulsatility Index, PI) after 3 weeks of sildenafil versus placebo. Secondary outcomes including non-inferiority of sildenafil vs cilostazol in effects on PI, percentage increase in MCA blood flow velocity and BOLD-fMRI response during inhalation of 4–6% carbon dioxide.

Discussion

Reduction in cerebral pulsatility and increased cerebrovascular reactivity during treatment with sildenafil would indicate potential benefit to prevent progression of SVD, suggesting a need for trials with clinical outcomes.

Trial Registration OxHARP is registered with ClinicalTrials.org, NCT03855332

Relationship between Residential Segregation, Later-Life Cognition, and Incident Dementia across Race/Ethnicity

Systemic racism leads to racial/ethnic residential segregation, which can result in health inequities. We examined if the associations between residential segregation and later-life cognition and dementia differed based on segregation measure and by participant race/ethnicity. Tests of memory (n = 4616), language (n = 4333), visuospatial abilities (n = 4557), and incident dementia (n = 4556) were analyzed in older residents of Northern Manhattan, New York (mean age: 75.7 years). Segregation was measured at the block group-level using three indices: dissimilarity, isolation, and interaction. We fit multilevel linear or Cox proportional hazards models and included a race/ethnicity × segregation term to test for differential associations, adjusting for socioeconomic and health factors. Living in block groups with higher proportions of minoritized people was associated with -0.05 SD lower language scores. Living in block groups with higher potential contact between racial/ethnic groups was associated with 0.06-0.1 SD higher language scores. The findings were less pronounced for other cognitive domains and for incident dementia. Non-Hispanic Black adults were most likely to experience negative effects of neighborhood segregation on cognition (language and memory) and dementia. All indices partly capture downstream effects of structural racism (i.e., unequal distributions of wealth/resources) on cognition. Therefore, desegregation and equitable access to resources have the potential to improve later-life cognitive health.

The role of urinary albumin-to-creatinine ratio as a biomarker to predict stroke: A meta-analysis and systemic review

Albuminuria excretion rate, calculated as urinary albumin-to-creatinine ratio (UACR), is used clinically to evaluate albuminuria. There are different attitudes to whether high UACR predicts higher risk of stroke. The aim of this study was to evaluate the relationship between UACR and stroke. Two investigators independently searched MEDLINE, EMBASE, Cochrane Controlled Trials Register Database, Scopus and Google Scholar from January 1966 through June 2021 were screened. In addition, a manual search was conducted using the bibliographies of original papers and review articles on this topic. Two blinded reviewers abstracted the data independently to a predefined form. Among the 10,939 initially identified studies, 7 studies with 159,302 subjects were finally included. It is demonstrated that UACR predicted an increased risk of stroke using cutoff value of either 0.43 (HR, 2.39; 95% CI: 1.24 - 4.61; P <0.01), 10 mg/g (HR, 1.60; 95% CI: 1.30 - 1.97; P < 0.01) or 30 mg/g (HR, 1.84; 95% CI: 1.49 - 2.28; P < 0.01). The overall analysis confirmed that high UACR was associated with an increased rate of stroke (HR, 1.81; 95% CI: 1.52 - 2.17; P < 0.01). Furthermore, High UACR predicted higher risk of stroke in local inhabitants (HR, 1.67; 95% CI: 1.17 – 2.37; P = 0.04), adults (HR, 2.21; 95% CI: 2.07 – 2.36; P < 0.01) or elderly adults (HR, 1.96; 95% CI: 1.56 – 2.46; P < 0.01). Whereas, high UACR was unable to predict stroke in patients with either T2DM (HR, 2.25; 95% CI: 0.55 – 9.17; P = 0.26) or hypertension (HR, 0.95; 95% CI: 0.28 – 3.22; P = 0.93). Another subgroup analysis revealed that high UACR was associated with increased risk of ischemic stroke (HR, 1.60; 95% CI: 1.43 - 1.80; P < 0.01), as well as hemorrhagic stroke (HR, 1.76; 95% CI: 1.22 - 1.45; P < 0.01). In conclusion, UACR is associated with an increased risk of hemorrhagic and ischemic stroke. UACR may be used as an indicator to predict stroke in non-diabetic and non-hypertensive subjects.

An ecological approach to understanding stroke experience and access to rehabilitation services in Ghana: A cross-sectional study

Despite a growing burden of stroke in low-middle-income countries, research on patient's experiences and access to rehabilitation services remains limited. This study explores the experiences of stroke patients in relation to access and use of stroke rehabilitation services, coping strategies and strategies to improve care in Ghana. A cross-sectional study was conducted. A total of 136 adult stroke patients hospitalised and subsequently discharged in three major referral hospitals in Ghana participated in the study. A paper-based questionnaire was used to collect data. Data were inputted into STATA version 12, cleaned and analysed using descriptive statistics and Chi-Square tests. Findings showed that stroke patients experience stroke differently. Early detection (awareness) of stroke symptoms at onset was low (29.4%). Hypertension was the major (58.1%) predisposing risk factor for stroke, followed by diabetes (14.7%). Multiple barriers impede access to outpatient rehabilitation services: high cost of medications (43.4%), transportation constraints (10.3%), long waiting time (6.6%), forgetfulness about appointment (4.4%), limited education on rehabilitation (20.6%), lack of community support (12.5%) and ineffective communication with healthcare providers (5.2%). Recommended strategies to improve access to rehabilitation care included public education on stroke and its associated risk, reduction in the cost of drugs and increased stroke rehabilitation funding by the NHIS, especially for physiotherapy consultation and training support to caregivers on patient care. Given the difference in stroke experience and barriers in accessing rehabilitation care, multi-level health policy and service delivery reforms are needed to improve access to rehabilitation care, including national public awareness campaigns on early signs of stroke and subsidised cost of stroke rehabilitation.

Association between widespread pain and dementia, Alzheimer's disease and stroke: a cohort study from the Framingham Heart Study

BACKGROUND AND OBJECTIVE

Chronic pain may be an early indicator of cognitive decline, but previous studies have not systematically examined the population-level associations between widespread pain and adverse cognitive outcomes and stroke. This study was designed to determine the association between widespread pain, a common subtype of chronic pain, and subsequent dementia, Alzheimer's disease dementia and stroke.

METHODS

This retrospective cohort study used data from the US community-based Framingham Heart Study. Pain status was assessed at a single time point between 1990 and 1994. Widespread pain was determined based on the Framingham Heart Study pain homunculus. Dementia follow-up occurred across a median of 10 years (IQR, 6-13 years) for persons who were dementia free at baseline. Proportional hazard models examined associations between widespread pain and incident dementia, Alzheimer's disease dementia and stroke.

RESULTS

A total of 347 (14.1%) subjects fulfilled the criteria for widespread pain, whereas 2117 (85.9%) subjects did not. Of 188 cases of incident all-cause dementia, 128 were Alzheimer's disease dementia. In addition, 139 patients suffered stroke during the follow-up period. After multivariate adjustment including age and sex, widespread pain was associated with 43% increase in all-cause dementia risk (HR: 1.43; 95% CI 1.06 to 1.92), 47% increase in Alzheimer's disease dementia risk (HR: 1.47; 95% CI 1.13 to 2.20) and 29% increase in stroke risk (HR: 1.29; 95% CI 1.08 to 2.54). Comparable results were shown in the subgroup of individuals over 65 years old.

CONCLUSION

Widespread pain was associated with an increased incidence of all-cause dementia, Alzheimer's disease dementia and stroke.

TRIAL REGISTRATION NUMBER

NCT00005121.

Physiological determinants of residual cerebral arterial pulsatility on best medical treatment after TIA or minor stroke

Cerebral arterial pulsatility is strongly associated with cerebral small vessel disease and lacunar stroke yet its dependence on central versus local haemodynamic processes is unclear. In a population-based study of patients on best medical managment, 4-6 weeks after a TIA or non-disabling stroke, arterial stiffness and aortic systolic, diastolic and pulse pressures were measured (Sphygmocor). Middle cerebral artery peak and trough flow velocities and Gosling's pulsatility index were measured by transcranial ultrasound. In 981 participants, aortic and cerebral pulsatility rose strongly with age in both sexes, but aortic diastolic pressure fell more with age in men whilst cerebral trough velocity fell more in women. There was no significant association between aortic systolic or diastolic blood pressure with cerebral peak or trough flow velocity but aortic pulse pressure explained 37% of the variance in cerebral arterial pulsatility, before adjustment, whilst 49% of the variance was explained by aortic pulse pressure, arterial stiffness, age, gender and cardiovascular risk factors. Furthermore, arterial stiffness partially mediated the relationship between aortic and cerebral pulsatility. Overall, absolute aortic pressures and cerebral blood flow velocity were poorly correlated but aortic and cerebral pulsatility were strongly related, suggesting a key role for transmission of aortic pulsatility to the brain.

Mediterranean Diet and Neurodegenerative Diseases: The Neglected Role of Nutrition in the Modulation of the Endocannabinoid System

Neurodegenerative disorders are a widespread cause of morbidity and mortality worldwide, characterized by neuroinflammation, oxidative stress and neuronal depletion. The broad-spectrum neuroprotective activity of the Mediterranean diet is widely documented, but it is not yet known whether its nutritional and caloric balance can induce a modulation of the endocannabinoid system. In recent decades, many studies have shown how endocannabinoid tone enhancement may be a promising new therapeutic strategy to counteract the main hallmarks of neurodegeneration. From a phylogenetic point of view, the human co-evolution between the endocannabinoid system and dietary habits could play a key role in the pro-homeostatic activity of the Mediterranean lifestyle: this adaptive balance among our ancestors has been compromised by the modern Western diet, resulting in a “clinical endocannabinoid deficiency syndrome”. This review aims to evaluate the evidence accumulated in the literature on the neuroprotective, immunomodulatory and antioxidant properties of the Mediterranean diet related to the modulation of the endocannabinoid system, suggesting new prospects for research and clinical interventions against neurodegenerative diseases in light of a nutraceutical paradigm.

Defining brain health: A concept analysis

OBJECTIVES

Brain health is an important focus for coming decades due to population ageing. Although the term 'brain health' is increasingly used in lay and professional settings, a clear definition of the term is lacking. We conducted an analysis of the concept of brain health to inform policy, practice, and research.

METHODS

We applied a hybrid concept analysis method involving three stages: (1) a review of the extant literature for definitions of brain health; (2) field work, involving an international survey of 'brain health' researchers and practitioners; and (3) a final analysis, integrating the findings into a working definition and model.

RESULTS

Our review of the literature identified 13 articles defining brain health, six of which proposed their own definition. Our survey revealed that the term 'brain health' was used in diverse ways based on different theoretical frameworks. From the review and survey, we extracted attributes, antecedents, and consequences of brain health. These were synthesized into a definition of brain health as a life-long, multidimensional, dynamic state consisting of cognitive, emotional and motor domains underpinned by physiological processes and can be objectively measured and subjectively experienced. It is influenced by eco-biopsychosocial determinants.

CONCLUSION

This working definition of brain health is a foundation for developing policy, practice, research and advocacy. The definition needs to be operationalised through further development of empirical referents, including cross-cultural understanding, adaptation and validation.

Associations between 20-year lipid variability throughout young adulthood and midlife cognitive function and brain integrity

BACKGROUND

Little is known about long-term lipid variability in young adulthood in relation to cognitive function and brain integrity in midlife.

METHODS

We studied 3,328 adults from the Coronary Artery Risk Development in Young Adults. We defined low- and high- density lipoprotein (LDL, HDL) variability as the intra-individual standard deviation of lipid measurements over 20 years of young adulthood (1985-2005). Cognitive tests were administered in 2010. Brain scans were performed in 2010 on 714 participants. To facilitate comparison, cognitive tests and brain metrics were z-scored.

RESULTS

Mean age at baseline was 25.4 years. Higher 20-year LDL variability was associated with worse verbal memory in midlife (β=-0.25, 95% CI [-0.42, -0.08]), adjusted for important covariates. Higher 20-year HDL variability was associated with worse processing speed in midlife (β=-0.80, 95% CI [-1.18, -0.41]) and brain integrity, e.g. smaller total brain volume (β=-0.58, 95% CI [-0.82, -0.34]) and worse total brain fractional anisotropy (β=-1.13, 95% CI [-1.87, -0.39]).

CONCLUSIONS

Higher long-term lipid variability in adulthood was associated with worse cognition and brain integrity in midlife, in a relatively young cohort.

Association of Racial Residential Segregation Throughout Young Adulthood and Cognitive Performance in Middle-aged Participants in the CARDIA Study

Importance

Neighborhood-level residential segregation is implicated as a determinant for poor health outcomes in black individuals, but it is unclear whether this association extends to cognitive aging, especially in midlife.

Objective

To examine the association between cumulative exposure to residential segregation during 25 years of young adulthood among black individuals and cognitive performance in midlife.

Design, Setting, and Participants

The ongoing prospective cohort Coronary Artery Risk Development in Young Adults (CARDIA) Study recruited 5115 black and white participants aged 18 to 30 years from 4 field centers at the University of Alabama, Birmingham; University of Minnesota, Minneapolis; Northwestern University, Chicago, Illinois; and Kaiser Permanente, Oakland, California. Data were acquired from February 1985 to May 2011. Among the surviving CARDIA cohort, 3671 (71.8%) attended examination year 25 of the study in 2010, when cognition was measured, and 3008 (81.9%) of those completed the cognitive assessments. To account for time-varying confounding and differential censoring, marginal structural models using inverse probability weighting were applied. Data were analyzed from April 16 to July 20, 2019.

Main Outcomes and Measures

Racial residential segregation was measured using the Getis-Ord Gi* statistic, and the mean cumulative exposure to segregation was calculated across 6 follow-up visits from baseline to year 25 of the study, then categorized into high, medium, and low segregation. Cognitive function was measured at year 25 of the study, using the Digit Symbol Substitution Test (DSST), Stroop color test (reverse coded), and Rey Auditory Verbal Learning Test. To facilitate comparison of estimates, z scores were calculated for all cognitive tests.

Results

A total of 1568 black participants with available cognition data were included in the analysis. At baseline, participants had a mean (SD) age of 25 (4) years and consisted of 936 women (59.7%). Greater cumulative exposure to segregated neighborhoods was associated with a worse DSST z score (for high segregation, β = -0.37 [95% CI, -0.61 to -0.13]; for medium segregation, β = -0.25 [95% CI, -0.51 to 0.0002]) relative to exposure to low segregation.

Conclusions and Relevance

In this cohort study, exposure to residential segregation throughout young adulthood was associated with worse processing speed among black participants as early as in midlife. This association may potentially explain black-white disparities in dementia risk at older age.

Neuroblast senescence in the aged brain augments natural killer cell cytotoxicity leading to impaired neurogenesis and cognition

Normal aging is accompanied by escalating systemic inflammation. Yet the potential impact of immune homeostasis on neurogenesis and cognitive decline during brain aging have not been previously addressed. Here we report that natural killer (NK) cells of the innate immune system reside in the dentate gyrus neurogenic niche of aged brains in humans and mice. In situ expansion of these cells contributes to their abundance, which dramatically exceeds that of other immune subsets. Neuroblasts within the aged dentate gyrus display a senescence-associated secretory phenotype and reinforce NK cell activities and surveillance functions, which result in NK cell elimination of aged neuroblasts. Genetic or antibody-mediated depletion of NK cells leads to sustained improvements in neurogenesis and cognitive function during normal aging. These results demonstrate that NK cell accumulation in the aging brain impairs neurogenesis, which may serve as a therapeutic target to improve cognition in the aged population.

Measures of Adiposity and Alzheimer's Disease-Related MRI Markers: The Northern Manhattan Study

BACKGROUND

Adiposity may increase risk for dementia and Alzheimer's disease (AD), but mechanisms are unclear.

OBJECTIVE

To examine associations between measures of adiposity with AD-signature region cortical thickness and hippocampal volume.

METHODS

We used data from the Northern Manhattan Study, a clinically stroke-free cohort of mostly Hispanic participants. Exposures of interest included body mass index (BMI), waist-hip-ratio (WHR), waist circumference (WC), and adiponectin concentration, measured at study entry. AD-signature region cortical thickness and hippocampal volume were obtained using Freesurfer. We estimated associations using multivariable linear regression, adjusting for sociodemographics and health behaviors. We re-examined estimates after adjustment for APOEɛ4 allele status or carotid intima-media thickness (cIMT), among those cognitively unimpaired, and after weighting for the inverse probability of selection into the MRI sub-study. We also repeated analyses for cortical thickness in non-AD signature regions.

RESULTS

The sample (N = 947, 63% women, 66% Hispanic/Latino, 26% obese) had a mean (SD) age = 63 (8) years. Greater BMI and WC (both z-scored) were associated with thinner AD-signature region cortex (also z-scored) (BMI: β [95% CI] = -0.09 [-0.18, -0.01], WC: β [95% CI] = -0.11 [-0.20, -0.02]). We did not find evidence that adiposity was related to hippocampal volume. Results were consistent after adjustment for APOEɛ4 allele status or cIMT, after weighting for selection, among those cognitively unimpaired, and for non-AD signature region cortical thickness.

CONCLUSION

Greater BMI and WC were related to cortical thinning within and outside the AD-signature region, suggesting a global effect not specific to AD.

Hypertensive Exposure Markers by MRI in Relation to Cerebral Small Vessel Disease and Cognitive Impairment

OBJECTIVES

This study sought to investigate the extent of hypertensive exposure as assessed by cardiovascular magnetic resonance imaging (MRI) in relation to cerebral small vessel disease (CSVD) and cognitive impairment, with the aim of understanding the role of hypertension in the early stages of deteriorating brain health.

BACKGROUND

Preserving brain health into advanced age is one of the great challenges of modern medicine. Hypertension is thought to induce vascular brain injury through exposure of the cerebral microcirculation to increased pressure/pulsatility. Cardiovascular MRI provides markers of (subclinical) hypertensive exposure, such as aortic stiffness by pulse wave velocity (PWV), left ventricular (LV) mass index (LVMi), and concentricity by mass-to-volume ratio.

METHODS

A total of 559 participants from the Heart-Brain Connection Study (431 patients with manifest cardiovascular disease and 128 control participants), age 67.8 ± 8.8 years, underwent 3.0-T heart-brain MRI and extensive neuropsychological testing. Aortic PWV, LVMi, and LV mass-to-volume ratio were evaluated in relation to presence of CSVD and cognitive impairment. Effect modification by patient group was investigated by interaction terms; results are reported pooled or stratified accordingly.

RESULTS

Aortic PWV (odds ratio [OR]: 1.17; 95% confidence interval [CI]: 1.05 to 1.30 in patient groups only), LVMi (in carotid occlusive disease, OR: 5.69; 95% CI: 1.63 to 19.87; in other groups, OR: 1.30; 95% CI: 1.05 to 1.62]) and LV mass-to-volume ratio (OR: 1.81; 95% CI: 1.46 to 2.24) were associated with CSVD. Aortic PWV (OR: 1.07; 95% CI: 1.02 to 1.13) and LV mass-to-volume ratio (OR: 1.27; 95% CI: 1.07 to 1.51) were also associated with cognitive impairment. Relations were independent of sociodemographic and cardiac index and mostly persisted after correction for systolic blood pressure or medical history of hypertension. Causal mediation analysis showed significant mediation by presence of CSVD in the relation between hypertensive exposure markers and cognitive impairment.

CONCLUSIONS

The extent of hypertensive exposure is associated with CSVD and cognitive impairment beyond clinical blood pressure or medical history. The mediating role of CSVD suggests that hypertension may lead to cognitive impairment through the occurrence of CSVD.

Association of White Matter Hyperintensities and Cardiovascular Disease

Cardiac and cerebrovascular diseases are currently the leading causes of mortality and disability worldwide. Both the heart and brain display similar vascular anatomy, with large conduit arteries running on the surface of the organ providing tissue perfusion through an intricate network of penetrating small vessels. Both organs rely on fine tuning of local blood flow to match metabolic demand. Blood flow regulation requires adequate functioning of the microcirculation in both organs, with loss of microvascular function, termed small vessel disease (SVD) underlying different potential clinical manifestations. SVD in the heart, known as coronary microvascular dysfunction, can cause chronic or acute myocardial ischemia and may lead to development of heart failure. In the brain, cerebral SVD can cause an acute stroke syndrome known as lacunar stroke or more subtle pathological alterations of the brain parenchyma, which may eventually lead to neurological deficits or cognitive decline in the long term. Coronary microcirculation cannot be visualized in vivo in humans, and functional information can be deduced by measuring the coronary flow reserve. The diagnosis of cerebral SVD is largely based on brain magnetic resonance imaging, with white matter hyperintensities, microbleeds, and brain atrophy reflecting key structural changes. There is evidence that such structural changes reflect underlying cerebral SVD. Here, we review interactions between SVD and cardiovascular risk factors, and we discuss the evidence linking cerebral SVD with large vessel atheroma, atrial fibrillation, heart failure, and heart valve disease.

Cognitive functioning and lifetime major depressive disorder in UK Biobank

BACKGROUND

Cognitive impairment associated with lifetime major depressive disorder (MDD) is well-supported by meta-analytic studies, but population-based estimates remain scarce. Previous UK Biobank studies have only shown limited evidence of cognitive differences related to probable MDD. Using updated cognitive and clinical assessments in UK Biobank, this study investigated population-level differences in cognitive functioning associated with lifetime MDD.

METHODS

Associations between lifetime MDD and cognition (performance on six tasks and general cognitive functioning [g-factor]) were investigated in UK Biobank (N-range 7,457-14,836, age 45-81 years, 52% female), adjusting for demographics, education, and lifestyle. Lifetime MDD classifications were based on the Composite International Diagnostic Interview. Within the lifetime MDD group, we additionally investigated relationships between cognition and (a) recurrence, (b) current symptoms, (c) severity of psychosocial impairment (while symptomatic), and (d) concurrent psychotropic medication use.

RESULTS

Lifetime MDD was robustly associated with a lower g-factor (β = -0.10, PFDR = 4.7 × 10-5), with impairments in attention, processing speed, and executive functioning (β ≥ 0.06). Clinical characteristics revealed differential profiles of cognitive impairment among case individuals; those who reported severe psychosocial impairment and use of psychotropic medication performed worse on cognitive tests. Severe psychosocial impairment and reasoning showed the strongest association (β = -0.18, PFDR = 7.5 × 10-5).

CONCLUSIONS

Findings describe small but robust associations between lifetime MDD and lower cognitive performance within a population-based sample. Overall effects were of modest effect size, suggesting limited clinical relevance. However, deficits within specific cognitive domains were more pronounced in relation to clinical characteristics, particularly severe psychosocial impairment.

Links Between Adiponectin and Dementia: From Risk Factors to Pathophysiology

With the aging population, dementia is becoming one of the most serious and troublesome global public health issues. Numerous studies have been seeking for effective strategies to delay or block its progression, but with little success. In recent years, adiponectin (APN) as one of the most abundant and multifunctional adipocytokines related to anti-inflammation, regulating glycogen metabolism and inhibiting insulin resistance (IR) and anti-atherosclerosis, has attracted widespread attention. In this article, we summarize recent studies that have contributed to a better understanding of the extent to which APN influences the risks of developing dementia as well as its pathophysiological progression. In addition, some controversial results interlinked with its effects on cognitive dysfunction diseases will be critically discussed. Ultimately, we aim to gain a novel insight into the pleiotropic effects of APN levels in circulation and suggest potential therapeutic target and future research strategies.

A Taxonomy of Brain-Behavior Relationships After Stroke

Purpose Understanding the brain basis of language and cognitive outcomes is a major goal of aphasia research. Prior studies have not often considered the many ways that brain features can relate to behavioral outcomes or the mechanisms underlying these relationships. The purpose of this review article is to provide a new framework for understanding the ways that brain features may relate to language and cognitive outcomes from stroke. Method Brain-behavior relationships that may be important for aphasia outcomes are organized into a taxonomy, including features of the lesion and features of brain tissue spared by the lesion. Features of spared brain tissue are categorized into those that change after stroke and those that do not. Features that change are further subdivided, and multiple mechanisms of brain change after stroke are discussed. Results Features of the stroke, including size, location, and white matter damage, relate to many behavioral outcomes and likely account for most of the variance in outcomes. Features of the spared brain tissue that are unchanged by stroke, such as prior ischemic disease in the white matter, contribute to outcomes. Many different neurobiological and behavioral mechanisms may drive changes in the brain after stroke in association with behavioral recovery. Changes primarily driven by neurobiology are likely to occur in brain regions with a systematic relationship to the stroke distribution. Changes primarily driven by behavior are likely to occur in brain networks related to the behavior driving the change. Conclusions Organizing the various hypothesized brain-behavior relationships according to this framework and considering the mechanisms that drive these relationships may help investigators develop specific experimental designs and more complete statistical models to explain language and cognitive abilities after stroke. Eight main recommendations for future research are provided. Presentation Video https://doi.org/10.23641/asha.10257578.

Causal Effect of Lp(a) [Lipoprotein(a)] Level on Ischemic Stroke and Alzheimer Disease: A Mendelian Randomization Study

Background and Purpose- Stroke and Alzheimer disease are 2 major causes of neurological disability in aged people and shared overlapping predictors. In recent prospective studies, high Lp(a) [lipoprotein(a)] level is associated with high risk of stroke but low risk of Alzheimer disease. Whether this reflects a causal association remains to be established. The aim of this study is to examine the causal associations of Lp(a) concentrations on ischemic stroke, ischemic stroke subtypes, and Alzheimer disease. Methods- We used 9 single-nucleotide polymorphisms associated with Lp(a) concentrations as instrumental variables. Summary-level data on ischemic stroke and its subtypes were obtained from the Multiancestry Genome-Wide Association Study of Stroke consortium with European individuals ≤446 696 individuals. Summary-level data on Alzheimer disease were obtained from the International Genomics of Alzheimer Project With European individuals ≤54 162 individuals. Two-sample Mendelian randomization (MR) estimates were calculated with inverse-variance weighted, penalized inverse-variance weighted, simple median, weighted median, and MR Pleiotropy Residual Sum and Outlier approaches, and MR-Egger regression was used to explore pleiotropy. Results- Genetically predicted 1-SD log-transformed increase in Lp(a) concentrations was associated with a substantial increase in risk of large artery stroke (odds ratio, 1.20; 95% CI, 1.11-1.30; P<0.001) and a reduce in risk of small vessel stroke (odds ratio, 0.92; 95% CI, 0.88-0.97; P=0.001) and Alzheimer disease (odds ratio, 0.94; 95% CI, 0.91-0.97; P<0.001) using inverse-variance weighted method. No significant association was observed for total ischemic stroke or cardioembolic stroke. MR-Egger indicated no evidence of pleiotropic bias. Results were broadly consistent in sensitivity analyses using penalized inverse-variance weighted, simple median, weighted median, and MR Pleiotropy Residual Sum and Outlier approaches accounting for potential genetic pleiotropy or outliers. Conclusions- This study provides evidence to support that high Lp(a) concentrations was causally associated with an increased risk of large artery stroke but a decreased risk of small vessel stroke and Alzheimer disease. The mechanism underlying the double-edged sword effect of Lp(a) concentrations on neurological system requires further investigation.

Homocysteine, rather than age of onset, is a better predictor for cognitive function in older adults with bipolar disorder

OBJECTIVES

The association between older-age bipolar disorder and cognitive impairments may be mediated by vascular burden. The aim of the study was to examine the difference of cognitive function between older people with late-onset bipolar disorder (LOBD) and early-onset bipolar disorder (EOBD) by considering rigorous vascular risk burden evaluation, comprehensive cognitive tests, and relevant biochemistry data.

METHODS

We recruited 95 outpatients aged over 55 with a DSM-IV-TR diagnosis of bipolar I disorder. Fifty had LOBD, defined by age of onset after 40. Cognitive function was evaluated through a battery of tests assessing verbal memory, attention/speed, visuospatial function, verbal fluency, and cognitive flexibility. Vascular risk assessments included individual disorders, 10-year Framingham cardiovascular risk scores, and serum levels of homocysteine, vitamin B12, folate, and triiodothyronine.

RESULTS

No differences were observed between LOBD and EOBD on any cognitive test after adjusting for potential confounders. In addition to age and educational years, multiple linear regression analyses indicated significantly negative associations between serum homocysteine levels and cognitive performances in attention, psychomotor speed, verbal memory, and executive function.

CONCLUSIONS

Among older people with bipolar disorder, LOBD is not associated with more cognitive dysfunction in this study. However, higher serum homocysteine levels were significantly associated with worse cognitive performance in this particular group. Clinicians therefore have to pay attention to the cognitive function in older bipolar patients with higher levels of homocysteine.

Association Between Statin Use and Risk of Dementia After a Concussion

Importance

Concussions are an acute injury that may lead to chronic disability, while statin use might improve neurologic recovery.

Objective

To test whether statin use is associated with an increased or decreased risk of subsequent dementia after a concussion.

Design, Setting, and Participants

Large extended population-based double cohort study in Ontario, Canada, from April 1, 1993, to April 1, 2013 (enrollment), and continued until March 31, 2016 (follow-up). Dates of analysis were April 28, 2014, through March 21, 2019. Participants were older adults diagnosed as having a concussion, excluding severe cases resulting in hospitalization, individuals with a prior diagnosis of dementia or delirium, and those who died within 90 days.

Exposure

Statin prescription within 90 days after a concussion.

Main Outcome and Measure

Long-term incidence of dementia.

Results

This study identified 28 815 patients diagnosed as having a concussion (median age, 76 years; 61.3% female), of whom 7058 (24.5%) received a statin, and 21 757 (75.5%) did not receive a statin. A total of 4727 patients subsequently developed dementia over a mean follow-up of 3.9 years, equal to an incidence of 1 case per 6 patients. Patients who received a statin had a 13% reduced risk of dementia compared with patients who did not receive a statin (relative risk, 0.87; 95% CI, 0.81-0.93; P < .001). The decreased risk of dementia associated with statin use applied to diverse patient groups, remained independent of other cardiovascular medication use, intensified over time, was distinct from the risk of subsequent depression, and was not observed in patients after an ankle sprain.

Conclusions and Relevance

In this study, older adults had a substantial long-term risk of dementia after a concussion, which was associated with a modest reduction among patients receiving a statin.

Mediterranean Diet in Preventing Neurodegenerative Diseases

PURPOSE OF REVIEW

We reviewed the most recent literature examining the associations between the Mediterranean-style diet (MD), neurodegenerative diseases, and markers and mechanisms of neurodegeneration.

RECENT FINDINGS

Most, but not all, epidemiologic studies report a protective association between MD adherence, cognitive impairment, and brain health. Data from clinical trials supporting these observational findings are also emerging. Limited evidence suggests that MD adherence may be protective for Parkinson's disease risk. Mechanistically, plant polyphenols may activate similar molecular pathways as caloric restriction diets, which helps explain the neuroprotective properties of the MD. Evidence for cognitive disorders is abundant, but there is a dearth of literature for other neurodegenerative disorders and for markers of neurodegeneration. Further research is needed to elucidate the protective role of MD on neurodegeneration, the most salient components of the MD, and the most sensitive time periods over the lifecourse at which the MD may exert its effects.

Measures of obesity are associated with MRI markers of brain aging: The Northern Manhattan Study

OBJECTIVE

To examine associations between measures of obesity in middle to early-old age with later-life MRI markers of brain aging.

METHODS

We analyzed data from the Northern Manhattan MRI Sub-Study (n = 1,289). Our exposures of interest were body mass index (BMI), waist circumference (WC), waist-to-hip ratio, and plasma adiponectin levels. Our outcomes of interest were total cerebral volume (TCV), cortical thickness, white matter hyperintensity volume (WMHV), and subclinical brain infarcts (SBI). Using multivariable linear and logistic regression models adjusted for sociodemographics, health behaviors, and vascular risk factors, we estimated β coefficients (or odds ratios) and 95% confidence intervals (CIs) and tested interactions with age, sex, and race/ethnicity.

RESULTS

On average at baseline, participants were aged 64 years and had 10 years of education; 60% were women and 66% were Caribbean Hispanic. The mean (SD) time lag between baseline and MRI was 6 (3) years. Greater BMI and WC were significantly associated with thinner cortices (BMI β [95% CI] -0.089 [-0.153, -0.025], WC β [95% CI] -0.103 [-0.169, -0.037]) in fully adjusted models. Similarly, compared to those with BMI <25, obese participants (BMI ≥30) exhibited smaller cortical thickness (β [95% CI] -0.207 [-0.374, -0.041]). These associations were particularly evident for those aged <65 years. Similar but weaker associations were observed for TCV. Most associations with WMHV and SBI did not reach statistical significance.

CONCLUSIONS

Adiposity in early-old age is related to reduced global gray matter later in life in this diverse sample. Future studies are warranted to elucidate causal relationships and explore region-specific associations.

Metabolic Syndrome, Mild Cognitive Impairment, and Dementia: A Meta-Analysis of Longitudinal Studies

OBJECTIVE

A systematic review and a meta-analysis of both clinical and population-based studies was undertaken according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement to clarify whether Metabolic Syndrome (MetS) is a risk or a protective factor for incident dementia, Alzheimer disease (AD), and vascular dementia (VaD), and whether it's involved in progression to dementia in patients affected by mild cognitive impairment (MCI).

METHODS

Search terms included ("metabolic syndrome" OR "syndrome x" OR "plurimetabolic syndrome") AND ("dementia" OR "Alzheimer disease" OR "vascular dementia" OR "mild cognitive impairment" OR "MCI"). Research was restricted to articles published in English between January 1, 2000 and August 31, 2018. No age limit was set.

RESULTS

At the end of the selection procedure, nine longitudinal studies were selected for the meta-analysis: six studies enrolled cognitively well-functioning participants and three studies involved MCI patients. A total of 18,313 participants aged older than 40 years with mean MetS prevalence of 22.7% were followed on average for 9.41years. A fixed model was used to estimate pooled hazard ratios and 95% confidence intervals.

CONCLUSION

No statistically significant pooled association emerged between MetS and incident dementia and AD. MetS increased the incidence of pure VaD. MetS increased the risk of progression from MCI to dementia. Follow-up length might be a key factor in investigating these associations further. Because MetS is constituted by a set of potentially modifiable factors, further studies with longer follow-up and repeated assessment of both MetS and cognitive status are desirable to draw definite conclusions.

Evidence of Concomitantly Increasing Stroke and Dementia Prevalence among those 80 Years and Older in Ontario, Canada, 2003-04 to 2012-13

Among those aged 80 years and older in Ontario, Canada, stroke and dementia incidence declined concomitantly from 2002-03 to 2013-14. This study aimed to report the concurrent temporal trends of stroke and dementia prevalence in Ontario among the same age demographic. The prevalence of both stroke and dementia increased from 2003-04 to 2012-13 in both sexes and the magnitude in which prevalence of dementia increased over time exceeded that of stroke. The substantial increase in the prevalence of dementia may be because of increased recognition and diagnoses of dementia and increased survival of stroke patients who are at higher risk of developing dementia.