Vascular risk factors, cognitive decline, and dementia

Neurologic impact of atrial fibrillation

PURPOSE OF REVIEW

Cognitive dysfunction is a complex condition that is becoming increasingly more prevalent. There has been growing acknowledgement that individuals with atrial fibrillation are at an increased risk of cognitive dysfunction beyond the association of age with both disorders. The purpose of this review is to explore the potential underlying mechanisms connecting atrial fibrillation and cognitive dysfunction and to examine the existing evidence for potential treatment options.

RECENT FINDINGS

Many mechanisms have been proposed for the association between cognitive dysfunction and atrial fibrillation. These include cerebral infarction (both micro and macro embolic events), cerebral microbleeds including those secondary to therapeutic anticoagulation, an increased inflammatory state, cerebral hypoperfusion, and a genetic predisposition to both diseases. Treatments designed to target each of these mechanisms have led to mixed results and there are no specific interventions that have definitively led to a reduction in the incidence of cognitive dysfunction.

SUMMARY

The relationship between cognitive dysfunction and atrial fibrillation remains poorly understood. Standard of care currently focuses on reducing risk factors, managing stroke risk, and maintaining sinus rhythm in appropriately selected patients. Further work needs to be conducted in this area to limit the progression of cognitive dysfunction in patients with atrial fibrillation.

Microvascular Dysfunction as a Possible Link Between Heart Failure and Cognitive Dysfunction

BACKGROUND

Microvascular function in the brain and heart may play an important role in the course of patients with heart failure (HF), but its relationship with ventricular and cognitive function is not well understood. We hypothesized that microvascular function in HF is closely related to both, cardiac and cognitive function.

METHODS

In healthy controls and symptomatic patients with HF (New York Heart Association functional class II or III), we used oxygenation-sensitive magnetic resonance imaging during a standardized breathing maneuver to determine the cerebral oxygenation reserve and the myocardial oxygenation reserve (MORE) as markers for microvascular function. A stepwise multivariable linear regression was performed to determine the variables that best predict changes in cerebral oxygenation reserve and MORE. We also measured cognitive function using the Montreal Cognitive Assessment test.

RESULTS

Twenty patients with HF (age 64.4±8.3 years; 50% female sex), and 21 healthy controls (age 55.0±5.1 years; 62% female sex) were included in the analysis. In patients with HF, cerebral oxygenation reserve and MORE were lower than in healthy controls (MORE, -0.1±3.3 versus 5.0±4.2, cerebral oxygenation reserve: 0.43±0.47 versus 1.21±0.60, respectively) as were Montreal Cognitive Assessment score results (HF, 23.9±3.7; healthy, 27.8±1.5; P=0.002). The Montreal Cognitive Assessment score in patients was correlated with cardiac output (r=0.55, P=0.011) and MORE (r=0.46, P=0.040). In addition to the presence of HF, significant predictors of cerebral and myocardial oxygenation reserve were cardiac output and end-diastolic volume, respectively.

CONCLUSIONS

Our results indicate that heart failure is an independent predictor of coronary and cerebral microvascular dysfunction as defined by a reduced response to a vasodilatory breathing maneuver. This impaired response was associated with reduced cognitive function.

Sex differences in longitudinal changes of episodic memory-related brain activity and cognition in cognitively unimpaired older adults with a family history of Alzheimer's disease

Episodic memory decline is an early symptom of Alzheimer's disease (AD) - a neurodegenerative disease that has a higher prevalence rate in older females compared to older males. However, little is known about why these sex differences in prevalence rate exist. In the current longitudinal task fMRI study, we explored whether there were sex differences in the patterns of memory decline and brain activity during object-location (spatial context) encoding and retrieval in a large sample of cognitively unimpaired older adults from the Pre-symptomatic Evaluation of Novel or Experimental Treatments for Alzheimer's Disease (PREVENT-AD) program who are at heightened risk of developing AD due to having a family history (+FH) of the disease. The goal of the study was to gain insight into whether there are sex differences in the neural correlates of episodic memory decline, which may advance knowledge about sex-specific patterns in the natural progression to AD. Our results indicate that +FH females performed better than +FH males at both baseline and follow-up on neuropsychological and task fMRI measures of episodic memory. Moreover, multivariate data-driven task fMRI analysis identified generalized patterns of longitudinal decline in medial temporal lobe activity that was paralleled by longitudinal increases in lateral prefrontal cortex, caudate and midline cortical activity during successful episodic retrieval and novelty detection in +FH males, but not females. Post-hoc analyses indicated that higher education had a stronger effect on +FH females neuropsychological scores compared to +FH males. We conclude that higher educational attainment may have a greater neuroprotective effect in older +FH females compared to +FH males.

Cardiovascular and metabolic health is associated with functional brain connectivity in middle-aged and older adults: Results from the Human Connectome Project-Aging study

Several cardiovascular and metabolic indicators, such as cholesterol and blood pressure have been associated with altered neural and cognitive health as well as increased risk of dementia and Alzheimer's disease in later life. In this cross-sectional study, we examined how an aggregate index of cardiovascular and metabolic risk factor measures was associated with correlation-based estimates of resting-state functional connectivity (FC) across a broad adult age-span (36-90+ years) from 930 volunteers in the Human Connectome Project Aging (HCP-A). Increased (i.e., worse) aggregate cardiometabolic scores were associated with reduced FC globally, with especially strong effects in insular, medial frontal, medial parietal, and superior temporal regions. Additionally, at the network-level, FC between core brain networks, such as default-mode and cingulo-opercular, as well as dorsal attention networks, showed strong effects of cardiometabolic risk. These findings highlight the lifespan impact of cardiovascular and metabolic health on whole-brain functional integrity and how these conditions may disrupt higher-order network integrity.

Chronic cerebral hypoperfusion: a critical feature in unravelling the etiology of vascular cognitive impairment

Vascular cognitive impairment (VCI) describes a wide spectrum of cognitive deficits related to cerebrovascular diseases. Although the loss of blood flow to cortical regions critically involved in cognitive processes must feature as the main driver of VCI, the underlying mechanisms and interactions with related disease processes remain to be fully elucidated. Recent clinical studies of cerebral blood flow measurements have supported the role of chronic cerebral hypoperfusion (CCH) as a major driver of the vascular pathology and clinical manifestations of VCI. Here we review the pathophysiological mechanisms as well as neuropathological changes of CCH. Potential interventional strategies for VCI are also reviewed. A deeper understanding of how CCH can lead to accumulation of VCI-associated pathology could potentially pave the way for early detection and development of disease-modifying therapies, thus allowing preventive interventions instead of symptomatic treatments.

Subjective Cognitive Decline Is Associated with Health-Related Quality of Life in the Middle-Aged to Elderly Population

BACKGROUND

Subjective cognitive decline (SCD) is considered to be a preliminary stage of dementia, and its prevalence is increasing with age.

OBJECTIVE

We aimed to study the association of SCD with health-related quality of life (HRQoL) in a large population-based sample.

METHODS

We analyzed data of the first 10,000 participants from the Hamburg City Health Study in Germany, a single center prospective cohort study, aged between 45 and 74 years that scored higher than 25 points in the Mini-Mental State Examination and had no known pre-existing dementia. HRQoL was assessed by the EQ-5D-5 L index, as well as the mental (MCS) and physical component summary (PCS) score of the Short Form-8. We computed linear regression analyses with 99% bias-corrected and accelerated (BCa) confidence intervals (CI) from 10,000 bootstrap samples to investigate the association between SCD and different indicators of HRQoL, while controlling for depression (PHQ-9), age, sex, and education as potential confounders.

RESULTS

Of 7,799 eligible participants (mean (SD) age 62.01 (8.41) years, 51.1% female), 3,708 (47.5%) reported SCD. Participants with SCD were older (62.7 versus 61.4 years) and more frequently female (54.2% versus 48.2%). SCD was independently associated with a lower EQ-5D-5 L index (β=-0.01, 99% BCa CI = [-0.020, -0.003], p < 0.001) and PCS (β=-1.00, 99% BCa CI = [-1.48, -0.51], p < 0.001) but not with MCS score.

CONCLUSION

In a population of middle-aged to elderly participants, there is a significant negative association between SCD and HRQoL across different instruments of HRQoL measurement independent of depression, demographics, and education.

Cardiometabolic multimorbidity and incident dementia: the Swedish twin registry

AIMS

Cardiometabolic diseases (CMDs), including diabetes, heart disease, and stroke, are established risk factors for dementia, but their combined impact has been investigated only recently. This study aimed to examine the association between mid- and late-life cardiometabolic multimorbidity and dementia and explore the role of genetic background in this association.

METHODS AND RESULTS

Within the Swedish Twin Registry, 17 913 dementia-free individuals aged ≥60 were followed for 18 years. CMDs [including age of onset in mid (60) or late (≥60) life] and dementia were ascertained from medical records. Cardiometabolic multimorbidity was defined as having ≥2 CMDs. Cox regression was used to estimate the CMD-dementia association in (i) a classical cohort study design and (ii) a co-twin study design involving 356 monozygotic and dizygotic pairs. By comparing the strength of the association in the two designs, the contribution of genetic background was estimated. At baseline, 3,312 (18.5%) participants had 1 CMD and 839 (4.7%) had ≥2 CMDs. Over the follow-up period, 3,020 participants developed dementia. In the classic cohort design, the hazard ratio (95% confidence interval) of dementia was 1.42 (1.27-1.58) for 1 CMD and 2.10 (1.73-2.57) for ≥2 CMDs. Dementia risk was stronger with mid-life as opposed to late-life CMDs. In the co-twin design, the CMD-dementia association was attenuated among monozygotic [0.99 (0.50-1.98)] but not dizygotic [1.55 (1.15-2.09)] twins, suggesting that the association was in part due to genetic factors common to both CMDs and dementia.

CONCLUSION

Cardiometabolic multimorbidity, particularly in mid-life, is associated with an increased risk of dementia. Genetic background may underpin this association.

Do cerebral microbleeds increase the risk of dementia? A systematic review and meta-analysis

Background

Dementia is a neurological disorder that commonly affects the elderly. Cerebral microbleeds (CMBs) are small, tiny lesions of the cerebral blood vessels and have been suggested as a possible risk factor for dementia. However, data about the association between CMBs and dementia risk are inconsistent and inconclusive. Therefore, we conducted this systematic review and meta-analysis to investigate the association between CMBs and dementia and highlight the possible explanations.

Methods

We followed the standard PRISMA statement and the Cochrane Handbook guidelines to conduct this study. First, we searched medical electronic databases for relevant articles. Then, we screened the retrieved articles for eligibility, extracted the relevant data, and appraised the methodological quality using the Newcastle-Ottawa Scale. Finally, the extracted data were pooled as risk ratios (RR) and hazard ratios (HR) in the random-effects meta-analysis model using the Review Manager software.

Results

We included nine studies with 14,221 participants and follow-up periods > 18 months. Overall, CMBs significantly increased the risk of developing dementia (RR 1.84, 95% CI [1.27-2.65]). This association was significant in the subgroups of studies on high-risk populations (RR 2.00, 95% CI [1.41-2.83], n = 1657 participants) and those in the general population (RR 2.30, 95% CI [1.25-4.26], n = 12,087 participants) but not in the memory clinic patients. Further, CMBs increased the risk of progressing to incident dementia over time (HR 2, 95% CI [1.54-2.61]).

Conclusion

Individuals with CMBs have twice the risk of developing dementia or progressing to MCI than those without CMBs. The detection of CMBs will help identify the population at higher risk of developing dementia. Physicians should educate individuals with CMBs and their families on the possibility of progressing to dementia or MCI. Regular cognitive assessments, cognitive training, lifestyle modifications, and controlling other dementia risk factors are recommended for individuals with CMBs to decrease the risk of cognitive decline and dementia development.

Speech biomarkers of risk factors for vascular dementia in people with mild cognitive impairment

Introduction

In this study we intend to use speech analysis to analyze the cognitive impairments caused by pathologies of vascular origin such as diabetes, hypertension, hypercholesterolemia and heart disease, predictors of the development of vascular dementia.

Methods

In this study, 40 participants with mild cognitive impairment were asked to read while being recorded and they were inquired about their history of the aforementioned conditions. Their speech was then analyzed.

Results

We found that some speech parameters of frequencies and syllabic rhythm vary due to these pathologies. In addition, we conducted a discriminant analysis in which we found that diabetes and hypertension can be predicted with an accuracy over 95% with few speech parameters, and hypercholesterolemia and heart disease with an accuracy over 80%.

Discussion

The predictor parameters found are heterogeneous, including voice quality, amplitude, frequency, and rhythm parameters. This result may lead to investigate why such important qualitative changes occur in the voice of older adults with these pathologies. Rather than trying to find a diagnostic procedure already existing in classical medicine, we expect this finding to contribute to explore the causes and concomitant pathologies of these diseases. We discuss the implications of behavioral traits, such as speech, as digital biomarkers.

Interaction between Alzheimer's Disease and Cerebral Small Vessel Disease: A Review Focused on Neuroimaging Markers

Alzheimer's disease (AD) is characterized by the presence of β-amyloid (Aβ) and tau, and subcortical vascular cognitive impairment (SVCI) is characterized by cerebral small vessel disease (CSVD). They are the most common causes of cognitive impairment in the elderly population. Concurrent CSVD burden is more commonly observed in AD-type dementia than in other neurodegenerative diseases. Recent developments in Aβ and tau positron emission tomography (PET) have enabled the investigation of the relationship between AD biomarkers and CSVD in vivo. In this review, we focus on the interaction between AD and CSVD markers and the clinical effects of these two markers based on molecular imaging studies. First, we cover the frequency of AD imaging markers, including Aβ and tau, in patients with SVCI. Second, we discuss the relationship between AD and CSVD markers and the potential distinct pathobiology of AD markers in SVCI compared to AD-type dementia. Next, we discuss the clinical effects of AD and CSVD markers in SVCI, and hemorrhagic markers in cerebral amyloid angiopathy. Finally, this review provides both the current challenges and future perspectives for SVCI.

Phenotype-informed polygenic risk scores are associated with worse outcome in individuals at risk of Alzheimer's disease

Introduction

Patients with predementia Alzheimer's disease (AD) and at-risk subjects are targets for promising disease-modifying treatments, and improved polygenic risk scores (PRSs) could improve early-stage case selection.

Methods

Phenotype-informed PRSs were developed by selecting AD-associated variants conditional on relevant inflammatory or cardiovascular traits. The primary outcome was longitudinal changes in measures of AD pathology, namely development of pathological amyloid deposition, medial temporal lobe atrophy, and cognitive decline in a prospective cohort study including 394 adults without AD dementia.

Results

High-risk groups defined by phenotype-informed AD PRSs had significantly steeper volume decline in medial temporal cortices, and the high-risk group defined by the cardiovascular-informed AD PRS had significantly increased hazard ratio of pathological amyloid deposition, compared to low-risk groups.

Discussion

AD PRSs informed by inflammatory disorders or cardiovascular risk factors and diseases are associated with development of AD pathology markers and may improve identification of subjects at risk for progression of AD.

Relationships between educational attainment, hypertension, and amyloid negative subcortical vascular dementia: The brain-battering hypothesis

Purpose

Many epidemiological studies suggest that lower education levels and vascular risk factors increase the likelihood of developing Alzheimer's disease dementia (ADD) and subcortical vascular dementia (SVaD). However, whether the brain-battering hypothesis can explain the relationship between education levels and the clinical diagnosis of dementia remains controversial. The objective of this study was to investigate whether vascular risk factors mediate the association between education level and the diagnosis of amyloid-beta positive (Aβ+) ADD and amyloid-beta negative (Aβ-) SVaD.

Methods

We analyzed 376 participants with Aβ normal cognition (Aβ- NC), 481 with Aβ+ ADD, and 102 with Aβ- SVaD. To investigate the association of education level and vascular risk factors with these diagnoses, multivariable logistic regression analysis was used, with age, sex, and APOE ε4 carrier status used as covariates. Path analysis was performed to investigate the mediation effects of hypertension on the diagnosis of Aβ- SVaD.

Results

The Aβ- SVaD group (7.9 ± 5.1 years) had lower education levels than did the Aβ- NC (11.8 ± 4.8 years) and Aβ+ ADD (11.2 ± 4.9 years) groups. The frequencies of hypertension and diabetes mellitus were higher in the Aβ- SVaD group (78.4 and 32.4%, respectively) than in the Aβ- NC (44.4 and 20.8%) and Aβ+ ADD (41.8 and 15.8%, respectively) groups. Increased education level was associated with a lower risk of Aβ- SVaD [odds ratio (OR) 0.866, 95% confidence interval (CI), 0.824–0.911], but not Aβ+ ADD (OR 0.971, 95% CI 0.940–1.003). The frequency of hypertension was associated with a higher risk of developing Aβ- SVaD (OR 3.373, 95% CI, 1.908–5.961), but not Aβ+ ADD (OR 0.884, 95% CI, 0.653–1.196). In the path analysis, the presence of hypertension partially mediated the association between education level and the diagnosis of Aβ- SVaD.

Conclusion

Our findings revealed that education level might influence the development of Aβ- SVaD through the brain-battering hypothesis. Furthermore, our findings suggest that suitable strategies, such as educational attainment and prevention of hypertension, are needed for the prevention of Aβ- SVaD.

The Mediating Role of Cardiometabolic Dysregulation on the Relation Between Adverse Childhood Experiences and Adult Cognition

OBJECTIVE

Adverse childhood experiences (ACEs) are uncontrollable stressful events during early life that predispose adults to adverse health outcomes, such as impaired cognitive functioning. However, little is known about the factors indirectly impacting this relation. Biological dysregulation may be one pathway that can help explain the relations between ACEs and later cognition. The current study examined the mediating role of cardiometabolic dysregulation on the relation between ACEs and cognition.

METHODS

Our study gathered data from 1053 participants using three waves of the Midlife in the United States longitudinal study. Linear regression analyses and bootstrapped mediation analyses were performed to analyze the direct and indirect associations of cardiometabolic dysregulation on ACEs and cognition.

RESULTS

Our results showed a significant linear relationship between ACEs and cardiometabolic dysregulation ( b = 0.152, standard error [SE] = 0.056, p = .007), and a significant indirect association, such that cardiometabolic dysregulation mediated the relation between ACEs and cognitive status at wave II ( b = -0.007, SE = 0.004, p = .044) and cognitive status at wave III ( b = -0.006, SE = 0.003, p .042). There was no significant direct or indirect relation when cognitive change was the outcome variable.

CONCLUSIONS

The present study identifies a combined biological pathway that connects ACEs to cognition in late life. These findings supports the need to empirically determine biological mechanism that can be used to develop targeted clinical interventions to prevent the progression of chronic cognitive impairment.

The Relationship Between Cardiovascular Disease Risk Score and Postoperative Delirium: The PNDABLE Study

Objective

We aimed to investigate the relationship between Framingham Heart Study general cardiovascular disease risk score (FHS–CVD risk score) and postoperative delirium (POD) among patients who had unilateral total knee arthroplasty performed under epidural anesthesia. Furthermore, we examined whether such a hypothesized relationship was mediated by the cerebrospinal fluid (CSF) biomarkers.

Methods

A total of 750 participants were included in the current study. And the data were drawn from the database obtained from the Perioperative Neurocognitive Disorder And Biomarker Lifestyle (PNDABLE) study. The preoperative cognitive function of participants was measured by using Mini-Mental State Examination (MMSE). The incidence of POD was assessed using the Confusion Assessment Method (CAM). The POD severity was measured using the Memorial Delirium Assessment Scale (MDAS). The POD CSF biomarkers included in the current study were: Aβ42, T-tau, P-tau, Aβ42/T-tau, and Aβ42/P-tau. The level of the CSF biomarkers was measured using the enzyme-linked immune-sorbent assay (ELISA) in the PNDABLE study. Linear regression analysis was performed to examine the relationship between the FHS–CVD risk score and the POD CSF biomarkers. Logistic regression was used to analyze the relationship between FHS–CVD risk score, POD CSF biomarkers, and POD incidence. The proposed mediating effect of CSF biomarkers was evaluated using Mediation Analysis with 10,000 bootstrapped iterations. The receiver operating characteristic (ROC) curve is chosen as the evaluation metric for assessing the efficacy of the FHS–CVD risk score in predicting POD.

Results

In the PNDABLE study, the overall incidence of POD was 22.9% with 37.2% in the higher vascular risk group and 7.9% in the lower vascular risk group. Multiple linear regression models showed that a higher preoperative FHS–CVD risk score was positively correlated with CSF T-tau (β = 0.218, P = 0.015) and P-tau level (β = 0.309, P &lt; 0.001) in the higher vascular risk group. After adjusting for age (40–90 years), gender, education, MMSE, smoking history, drinking history, hypertension, diabetes, and the presence of CHD (cardiovascular heart disease), the results of the logistic regression analysis demonstrated the effect of Aβ42 (OR = 0.994, 95% CI 0.992–0.996, P &lt; 0.001), Aβ42/T-tau (OR = 0.353, 95% CI 0.254–0.491, P &lt; 0.001), and Aβ42/P-tau (OR = 0.744, 95% CI 0.684–0.809, P &lt; 0.001) in protecting patients against POD. However, the FHS–CVD risk score (OR = 1.142, 95% CI 1.017–1.282, P = 0.025) and the remaining two biomarkers: T-tau (OR = 1.005, 95% CI 1.004–1.007, P &lt; 0.001) and P-tau (OR = 1.045, 95%CI 1.029–1.062, P &lt; 0.001) were identified as the risk factors. Mediation analyses revealed that the association between FHS–CVD risk score and POD was partially mediated by T-tau (proportion: 31.6%) and P-tau (proportion: 23.6%). The predictive power of the FHS–CVD risk score was validated by the ROC curve with an AUC of 0.7364.

Conclusion

Higher vascular risk score is one of the preoperative risk factors for POD, which is partly mediated by CSF biomarker tau protein.

Clinical Trial Registration

[www.clinicaltrials.gov], identifier [ChiCTR2000033439].

Changes in pairwise functional connectivity associated with changes in cognitive performance in cognitively normal older individuals: A two-year observational study

Neurobiological substrates of cognitive decline in cognitively normal older individuals have been investigated by resting-state functional magnetic resonance imaging, but little is known about the relationship between longitudinal changes in the whole brain. In this study, we examined two-year changes in functional connectivity among 80 gray matter areas and investigated the relationship to two-year changes in cognitive performance. A cross-validated permutation variable importance measure was applied to select features related to a change in cognitive performance. Age-corrected changes in eleven pairs of functional connections were selected as important features, all related to brain areas that belong to the default mode network. A linear regression model with cross-validation demonstrated a mean correlation coefficient of 0.55 between measured and predicted changes in the cognitive composite score. These results suggest that intra- and inter-network connections in the default mode network are associated with cognitive changes over two years among cognitively normal individuals.

Liberating older adults from the bonds of vascular risk factors: What is their impact on financial capacity in amnestic mild cognitive impairment?

BACKGROUND

There is a pressing need to clarify whether vascular risk factors (VRFs) are related to the heterogeneous cognitive performance found in mild cognitive impairment (MCI) and whether the number of VRFs relates to financial capacity impairment in patients with amnestic MCI (aMCI).

METHODS

A total of 112 participants were divided into three groups: patients with single-domain aMCI, patients with multiple-domain aMCI, and healthy controls (HCs), while taking into consideration whether participants had a diagnosis of one VRF or disease, or more than one VRF or disease. Patients with aMCI with VRFs (one and more than one VRF) and HCs did not differ significantly in age, education, and sex. Mini-Mental State Examination, 15-item Geriatric Depression Scale, and Legal Capacity for Property Law Transactions Assessment Scale (LCPLTAS) were administered to all groups.

RESULTS

Diagnosis (P <0.001) and VRFs (P = 0.006) showed significant main effects on LCPLTAS but no interaction (P = 0.654). Patients with aMCI with high vascular burden were more frequently of the multiple-domain subtype, whereas patients with no vascular burden were more frequently of the single-domain subtype. A larger vascular burden is correlated with lower LCPLTAS scores.

DISCUSSION

Vascular burden plays an important role in the heterogeneity of aMCI by impairing financial capacity.

Glucose-lowering drugs, cognition, and dementia: The clinical evidence

Type 2 diabetes mellitus (T2DM) is an important risk factor for dementia. The possibility to mitigate this risk by controlling T2DM is compelling; however, different glucose-lowering drugs have different effects on the brain by virtue of their different mechanisms of action. The clinical and epidemiological data appear mixed, warranting careful critical evaluation of the human studies. Here we examine the evidence in the context of dementia prevention and treatment, both for people with and without T2DM. We discuss the evidence on this scaffold of research directions, identifying methodological complexities in the extant literature (e.g. comparator discrepancies, changes in the therapeutic landscape), and the implications of different outcome measures (e.g. neuropsychological). We consider possible implications of cerebrovascular protection vs. effects on progression of neurodegenerative proteinopathy, and we present a research roadmap for glucose-lowering drugs in cognitive neurology, including neuroimaging, and fluid biomarkers. We conclude that there is great potential to advance personalized strategies to prevent and treat dementia with glucose-lowering drugs.

Lifestyle affects amyloid burden and cognition differently in men and women

Objective

Evidence on associations of lifestyle factors with Alzheimer's pathology and cognition are ambiguous, potentially because they rarely addressed inter‐relationships of factors and sex effects. While considering these aspects, we examined the relationships of lifestyle factors with brain amyloid burden and cognition.

Methods

We studied 178 cognitively normal individuals (women, 49%; 65.0 [7.6] years) and 54 individuals with mild cognitive impairment (women, 35%; 71.3 [8.3] years) enrolled in a prospective study of volunteers who completed ¹⁸F‐Flutemetamol amyloid positron emission tomography. Using structural equation modeling, we examined associations between latent constructs representing metabolic/vascular risk, physical activity, and cognitive activity with global amyloid burden and cognitive performance. Furthermore, we investigated the influence of sex in this model.

Results

Overall, higher cognitive activity was associated with better cognitive performance and higher physical activity was associated with lower amyloid burden. The latter association was weakened to a nonsignificant level after excluding multivariate outliers. Examination of the moderating effect of sex in the model revealed an inverse association of metabolic/vascular risk with cognition in men, whereas in women metabolic/vascular risk trended toward increased amyloid burden. Furthermore, a significant inverse association between physical activity and amyloid burden was found only in men. Inheritance of an APOE4 allele was associated with higher amyloid burden only in women.

Interpretation

Sex modifies effects of certain lifestyle‐related factors on amyloid burden and cognition. Notably, our results suggest that the negative impact of metabolic/vascular risk influences the risk of cognitive decline and Alzheimer's disease through distinct paths in women and men. ANN NEUROL 2022;92:451–463

Prevalence and correlates of vision impairment and its association with cognitive impairment among older adults in India: a cross-sectional study

OBJECTIVE

This study aimed to investigate the predictors of vision impairment in old age and how impaired vision is associated with cognitive impairment among the ageing population.

DESIGN

A cross-sectional study was conducted using a large country-representative survey data.

SETTING AND PARTICIPANTS

This study used data from the 'Building a Knowledge Base on Population Ageing in India' survey, conducted in 2011. Participants included 9541 older adults aged 60 years and above.

PRIMARY AND SECONDARY OUTCOME MEASURES

The outcome variables were vision impairment and cognitive impairment. Descriptive statistics along with bivariate analysis were presented. Additionally, multivariable binary logistic regression analysis was performed to fulfil the objectives.

RESULTS

A proportion of 59.1% of the respondents had vision impairment. Nearly 60% of the participants had cognitive impairment. Those who had vision impairment were 11% more likely to have cognitive impairment compared to their counterparts (OR: 1.11, 95% CI: 1.01 to 1.23). low psychological health (OR: 1.55; 95% CI: 1.36 to 1.77), low activities of daily living (OR: 1.80; 95% CI: 1.43 to 2.27), low instrumental activities of daily living (OR: 1.26; 95% CI: 1.14 to 1.40), poor self-rated health (OR: 1.28; 95% CI: 1.15 to 1.41) and chronic morbidity (OR: 1.27; 95% CI: 1.14 to 1.41) were found to be risk factors for cognitive impairment among older adults.

CONCLUSIONS

Additional efforts in terms of advocacy, availability, affordability and accessibility especially in a country with big illiteracy issue are mandatory to increase the reach of eye-care services and reduce the prevalence of avoidable visual impairment and vision losses that lead to cognitive deficits among the older population.

Association Between Late-Life Neuropsychiatric Symptoms and Cognitive Decline in Relation to White Matter Hyperintensities and Amyloid Burden

BACKGROUND

Neuropsychiatric symptoms (NPS) among cognitively normal older adults are increasingly recognized as risk factors for cognitive decline and impairment. However, the underlying mechanisms remain unclear.

OBJECTIVE

To examine whether biomarkers of Alzheimer's disease (amyloid burden) and cerebrovascular disease (white matter hyperintensity (WMH) volume) modify the association between NPS and cognitive decline among cognitively unimpaired older adults.

METHODS

Analyses included 193 cognitively unimpaired participants (M age = 70 years) from the BIOCARD study, including 148 with PET amyloid and WMH biomarker data. NPS were measured with Neuropsychiatric Inventory and Geriatric Depression Scale scores. Linear mixed effects models were used to examine the association between baseline NPS and longitudinal cognitive trajectories (M follow-up = 3.05 years), using separate models for global, episodic memory, and executive function cognitive composite scores. In a subset of individuals with biomarker data, we evaluated whether WMH or cortical amyloid burden modified the relationship between NPS and cognitive change (as indicated by the NPS×biomarker×time interactions).

RESULTS

Higher baseline NPS were associated with lower executive function scores, but not a faster rate of decline in executive function. NPS symptoms were unrelated to the global or episodic memory composite scores, and there was little evidence of a relationship between NPS symptoms and cognitive change over time. The associations between NPS and cognitive decline did not differ by amyloid or WMH burden, and NPS were unrelated to amyloid and WMH burden.

CONCLUSION

These results suggest that the effect of neuropsychiatric symptoms on executive dysfunction may occur through mechanisms outside of amyloid and cerebrovascular disease.

Plasma Myeloperoxidase as a Potential Biomarker of Patient Response to Anti-Dementia Treatment in Alzheimer's Disease

BACKGROUND

Myeloperoxidase (MPO), a neutrophil-derived pro-inflammatory protein, co-localizes with amyloid-β (Aβ) plaques in Alzheimer's disease (AD). Anti-dementia treatment may facilitate efflux of Aβ and associated plaque proteins from the brain to the peripheral circulation, therefore providing potential biomarkers for the monitoring of donor response to drug treatment.

OBJECTIVE

We investigated the diagnostic utility of MPO as a biomarker of AD, and how anti-dementia treatment alters plasma MPO concentration.

METHODS

Thirty-two AD patients were recruited, and plasma collected pre-drug administration (baseline), and 1- and 6-months post-treatment. All patients received cholinesterase inhibitors (ChEIs). At baseline and 6 months, patients underwent neuropsychological assessment. Forty-nine elderly healthy individuals with normal cognitive status served as controls. Plasma MPO concentration was measured by ELISA.

RESULTS

AD drug naïve patients had similar plasma MPO concentration to their control counterparts (p > 0.05). Baseline MPO levels positively correlated with Neuropsychiatric Inventory score (r = 0.5080; p = 0.011) and carer distress (r = 0.5022; p = 0.012). Following 1-month ChEI treatment, 84.4% of AD patients exhibited increased plasma MPO levels (p < 0.001), which decreased at 6 months (p < 0.001). MPO concentration at 1 month was greatest in AD patients whose memory deteriorated during the study period (p = 0.028), and for AD patients with deterioration in Cornell assessment score (p = 0.044).

CONCLUSION

Whereas baseline MPO levels did not differentiate between healthy and AD populations, baseline MPO positively correlated with initial Neuropsychiatric Inventory evaluation. Post-treatment, transient MPO upregulation in ChEI-treated patients may reflect worse therapeutic outcome. Further studies are required to assess the potential of plasma MPO as an AD therapeutic biomarker.

Effect of Hypertension Duration and Blood Pressure Control During Early Adulthood on Cognitive Function in Middle Age

BACKGROUND

Elevated blood pressure (BP) is a risk factor for cognitive impairment.

OBJECTIVE

We aim to explore the association between the duration of hypertension in early adulthood, with cognitive function in midlife. Furthermore, we investigate whether this asssociation is altered among participants with controlled BP.

METHODS

This prospective study included 2,718 adults aged 18-30 years without hypertension at baseline who participated in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. Duration of hypertension was calculated based on repeat measurements of BP performed at 2, 5, 7, 10, 15, 20, and 25 years after baseline. Cognitive function was assessed at Year-25 using the Rey Auditory Verbal Learning Test (RAVLT), Digit Symbol Substitution Test (DSST), and Stroop test.

RESULTS

After multivariable adjustment, a longer hypertension duration was associated with worse verbal memory (RAVLT, p trend = 0.002) but not with processing speed (DSST, p trend = 0.112) and executive function (Stroop test, p trend = 0.975). Among subgroups of participants with controlled (BP < 140/90 mmHg) and uncontrolled (SBP≥140 mmHg or DBP≥90 mmHg) BP at the time of cognitive assessment (i.e., Year-25 BP), longer duration of hypertension was associated with worse verbal memory. Similar results were observed in subgroups with controlled and uncontrolled average BP prior to cognitive assessment.

CONCLUSION

Longer duration of hypertension during early adulthood is associated with worse verbal memory in midlife regardless of current or long-term BP control status. The potential risk of hypertension associated cognitive decline should not be overlooked in individuals with a long duration of hypertension, even if BP levels are controlled.

Dietary Regulation of Gut-Brain Axis in Alzheimer's Disease: Importance of Microbiota Metabolites

Alzheimer's disease (AD) is a neurodegenerative disease that impacts 45 million people worldwide and is ranked as the 6th top cause of death among all adults by the Centers for Disease Control and Prevention. While genetics is an important risk factor for the development of AD, environment and lifestyle are also contributing risk factors. One such environmental factor is diet, which has emerged as a key influencer of AD development/progression as well as cognition. Diets containing large quantities of saturated/trans-fats, refined carbohydrates, limited intake of fiber, and alcohol are associated with cognitive dysfunction while conversely diets low in saturated/trans-fats (i.e., bad fats), high mono/polyunsaturated fats (i.e., good fats), high in fiber and polyphenols are associated with better cognitive function and memory in both humans and animal models. Mechanistically, this could be the direct consequence of dietary components (lipids, vitamins, polyphenols) on the brain, but other mechanisms are also likely to be important. Diet is considered to be the single greatest factor influencing the intestinal microbiome. Diet robustly influences the types and function of micro-organisms (called microbiota) that reside in the gastrointestinal tract. Availability of different types of nutrients (from the diet) will favor or disfavor the abundance and function of certain groups of microbiota. Microbiota are highly metabolically active and produce many metabolites and other factors that can affect the brain including cognition and the development and clinical progression of AD. This review summarizes data to support a model in which microbiota metabolites influence brain function and AD.

Global cognitive performance at 4-year follow-up in individuals with atrial fibrillation-findings from The Irish Longitudinal Study on Ageing

INTRODUCTION

Atrial fibrillation (AF) has been proposed as a risk factor for cognitive impairment, even in the absence of a history of stroke. This study investigates whether AF is associated with increased risk of cognitive decline in a community-dwelling population of adults over the age of 50.

METHODS

Data from the 1st and 3rd waves of The Irish Longitudinal Study on Ageing (TILDA) were used (4-year follow-up period). TILDA is a large prospective cohort study of community-dwelling adults over the age of 50 in Ireland. AF was assessed via electrocardiogram. Global cognitive function was assessed at baseline and follow-up using Montreal Cognitive Assessment (MOCA). Analysis of global cognition was repeated stratifying by age. Mixed-effects Poisson regression was used to assess for change in rate of errors on MOCA and MOCA subdomains.

RESULTS

A total of 3,417 participants were included in the study. Results found that participants with AF had a greater increase in rate of errors on MOCA over 4-year follow-up (incident rate ratio (IRR) 1.18; 95% confidence interval (CI) 1.02, 1.37; P-value 0.023). However, this was no longer significant on controlling for age, sex and level of education (IRR 1.08; 95% CI 0.93, 1.25; P-value 0.332). There was no difference when stratifying by age group, or when separating MOCA into subdomains.

CONCLUSION

Individuals with AF were more likely to show an increase in rate of errors between waves 1 and 3 (4-year follow-up period) in the TILDA population; however, results were not significant when controlling for age, sex and level of education.

The Relationship Between Cardiovascular Health and Rate of Cognitive Decline in Young-Old and Old-Old Adults: A Population-Based Study

Background:

Modifiable vascular risk factors have been associated with late-life cognitive impairment. The Life Simple 7 (LS7) score comprises seven cardiovascular health metrics: smoking, diet, physical activity, body mass index, plasma glucose, total serum cholesterol, and blood pressure.

Objective:

To investigate the association between individual and composite LS7 metrics and rate of cognitive decline, and potential differences in these associations between young-old and old-old individuals.

Methods:

This cohort study included 1,950 participants aged≥60 years (M = 70.7 years) from the Swedish National Study on Aging and Care-Kungsholmen (SNAC-K), who underwent repeated neuropsychological testing (episodic and semantic memory, verbal fluency, processing speed, global cognition) across 12 years. The LS7 score was assessed at baseline and categorized as poor, intermediate, or optimal. Level and change in cognitive performance as a function of LS7 categories were estimated using linear mixed-effects models.

Results:

Having an optimal LS7 total score was associated with better performance (expressed in standard deviation units) at baseline for perceptual speed (β= 0.21, 95%CI 0.12–0.29), verbal fluency (β= 0.08, 0.00–0.16), and global cognition (β= 0.06, 0.00–0.12) compared to the poor group. Age-stratified analyses revealed associations for cognitive level and change only in the young-old (< 78 years) group. For the specific metrics, diverging patterns were observed for young-old and old-old individuals.

Conclusion:

Meeting the LS7 criteria for ideal cardiovascular health in younger old age is associated with slower rate of cognitive decline. However, the LS7 criteria may have a different meaning for cognitive function in very old adults.

Multidomain interventions: state-of-the-art and future directions for protocols to implement precision dementia risk reduction. A user manual for Brain Health Services-part 4 of 6

Although prevention of dementia and late-life cognitive decline is a major public health priority, there are currently no generally established prevention strategies or operational models for implementing such strategies into practice. This article is a narrative review of available evidence from multidomain dementia prevention trials targeting several risk factors and disease mechanisms simultaneously, in individuals without dementia at baseline. Based on the findings, we formulate recommendations for implementing precision risk reduction strategies into new services called Brain Health Services. A literature search was conducted using medical databases (MEDLINE via PubMed and SCOPUS) to select relevant studies: non-pharmacological multidomain interventions (i.e., combining two or more intervention domains), target population including individuals without dementia, and primary outcomes including cognitive/functional performance changes and/or incident cognitive impairment or dementia. Further literature searches covered the following topics: sub-group analyses assessing potential modifiers for the intervention effect on cognition in the multidomain prevention trials, dementia risk scores used as surrogate outcomes in multidomain prevention trials, dementia risk scores in relation to brain pathology markers, and cardiovascular risk scores in relation to dementia. Multidomain intervention studies conducted so far appear to have mixed results and substantial variability in target populations, format and intensity of interventions, choice of control conditions, and outcome measures. Most trials were conducted in high-income countries. The differences in design between the larger, longer-term trials that met vs. did not meet their primary outcomes suggest that multidomain intervention effectiveness may be dependent on a precision prevention approach, i.e., successfully identifying the at-risk groups who are most likely to benefit. One such successful trial has already developed an operational model for implementing the intervention into practice. Evidence on the efficacy of risk reduction interventions is promising, but not yet conclusive. More long-term multidomain randomized controlled trials are needed to fill the current evidence gaps, especially concerning low- and middle-income countries and integration of dementia prevention with existing cerebrovascular prevention programs. A precision risk reduction approach may be most effective for dementia prevention. Such an approach could be implemented in Brain Health Services.

Cognition effectiveness of continuous positive airway pressure treatment in obstructive sleep apnea syndrome patients with cognitive impairment: a meta-analysis

Obstructive sleep apnea (OSA) is a common respiratory disorder characterized by recurrent pharyngeal collapses during sleep leading to intermittent hypoxia and sleep disruption. Cognitive challenges and high risks of cognitive impairment, including Alzheimer's disease (AD), are closely associated with OSA. Currently, continuous positive airway pressure (CPAP) is widely used in the treatment of OSA. However, whether CPAP benefits cognitive functions in patients with OSA remains elusive. Here, we identified published studies through a systematic review of PubMed, Cochrane Library, Embase, Wanfang Data, CBM, and CNKI from January 1, 1970, to July 1, 2020. 288 patients from 7 articles (one was excluded in the meta-analysis for it was a follow-up study) were included in the present study. It revealed that cognitive functions of OSA patients with mild cognitive impairment (MCI) or AD were mildly but significantly improved after CPAP treatment (SMD 0.49, 95% CI 0.11-0.86), especially long-term CPAP treatment (SMD 0.56, 95% CI 0.10-1.02, p = 0.02), as measured by Mini-Mental State Examination (MMSE) (SMD 0.49, 95%CI 0.11-0.86). However, no significant cognition benefits were detected by the Montreal Cognitive Assessment (SMD 0.43, 95% CI 0.85-1.72). In terms of heterogeneity, cognitive improvements by CPAP were detectable on OSA patients either at a younger age or over longer periods of CPAP treatment. Therefore, our findings highlight the partial efficiency of CPAP treatment in cognition improvement of OSA patients with MCI or AD.

Processing speed is affected by early impairment in kidney function in the general elder population

Background

Chronic kidney disease, cardiovascular disease, and cognitive dysfunction are common in the elder population. There is evidence of a connection between these conditions, possibly by a shared vascular pathogenesis. Processing speed is commonly impaired in cerebrovascular disease.

Methods

The data was obtained from the population based study “Good aging in Skåne” (GÅS), and included 905 individuals (mean age = 68 years). We investigated the impact of impaired kidney function at baseline on the development of dementia, MCI, and impairment in specific cognitive domains at follow up 6 years later, using logistic regression models. Impaired kidney function was defined as GFR < 60 ml/min/1,73 m². GFR was estimated from creatinine and cystatin C, using the CKD-EPI formula. Function in the cognitive domains learning and memory, language, complex attention, executive function, perceptual-motor, as well as meta-memory, and global cognitive function, was assessed using a neuropsychological test battery consisting of 12 tests. We compared the test results from follow up, with the results obtained at baseline, using linear regression models in order to assess changes in performance in cognitive domains.

Results

At follow up, 14 and 158 participants had developed dementia and MCI, respectively. We did not find evidence that moderately impaired eGFR at baseline increased the odds of dementia or MCI. A decline in processing speed was associated with impaired kidney function.

Conclusions

The effect on processing speed could represent early vascular implications on cognition. Even at moderately impaired kidney function, overview of cardiovascular risk factors could potentially prevent further cognitive impairment.

Microvascular degeneration occurs before plaque onset and progresses with age in 3xTg AD mice

Heart disease and vascular disease positively correlate with the incidence of Alzheimer's disease (AD). Although there is ostensible involvement of dysfunctional cerebrovasculature in AD pathophysiology, the characterization of the specific changes and development of vascular injury during AD remains unclear. In the present study, we established a time-course for the structural changes and degeneration of the angioarchitecture in AD. We used cerebrovascular corrosion cast and µCT imaging to evaluate the geometry, topology, and complexity of the angioarchitecture in the brain of wild type and 3xTg AD mice. We hypothesized that changes to the microvasculature occur early during the disease, and these early identifiable aberrations would be more prominent in the brain subregions implicated in the cognitive decline of AD. Whole-brain analysis of the angioarchitecture indicated early morphological abnormalities and degeneration of microvascular networks in 3xTg AD mice. Our analysis of the hippocampus and cortical subregions revealed microvascular degeneration with onset and progression that was subregion dependent.

Coronary artery revascularizations and cognitive decline - A systematic review

Coronary artery disease (CAD) is a risk factor for cognitive decline. The aim of this study was to systematically review recent literature on whether coronary artery revascularizations are associated to cognitive decline and dementia. Pubmed, Scopus, and CINAHL (EBSCO) were searched systematically from January 2009 till September 2020. Studies were conducted on persons with CAD undergoing coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) procedure compared to other coronary artery disease treatments, and the outcome was cognitive decline or dementia. Altogether four of the 680 reviewed articles met inclusion criteria. Results were inconsistent, and the outcome measurements heterogeneous between studies. Our findings indicate an evidence gap in the current understanding of long-term outcomes following coronary artery revascularization. However, evidence of long-term effects on cognition would complement our understanding of their benefits. There is a need for more studies on long-term cognitive outcomes after coronary artery revascularizations.

Molecular Pathobiology of the Cerebrovasculature in Aging and in Alzheimers Disease Cases With Cerebral Amyloid Angiopathy

Cerebrovascular dysfunction and cerebral amyloid angiopathy (CAA) are hallmark features of Alzheimer's disease (AD). Molecular damage to cerebrovessels in AD may result in alterations in vascular clearance mechanisms leading to amyloid deposition around blood vessels and diminished neurovascular-coupling. The sequelae of molecular events leading to these early pathogenic changes remains elusive. To address this, we conducted a comprehensive in-depth molecular characterization of the proteomic changes in enriched cerebrovessel fractions isolated from the inferior frontal gyrus of autopsy AD cases with low (85.5 ± 2.9 yrs) vs. high (81 ± 4.4 yrs) CAA score, aged-matched control (87.4 ± 1.5 yrs) and young healthy control (47 ± 3.3 yrs) cases. We employed a 10-plex tandem isobaric mass tag approach in combination with our ultra-high pressure liquid chromatography MS/MS (Q-Exactive) method. Enriched cerebrovascular fractions showed very high expression levels of proteins specific to endothelial cells, mural cells (pericytes and smooth muscle cells), and astrocytes. We observed 150 significantly regulated proteins in young vs. aged control cerebrovessels. The top pathways significantly modulated with aging included chemokine, reelin, HIF1α and synaptogenesis signaling pathways. There were 213 proteins significantly regulated in aged-matched control vs. high CAA cerebrovessels. The top three pathways significantly altered from this comparison were oxidative phosphorylation, Sirtuin signaling pathway and TCA cycle II. Comparison between low vs. high CAA cerebrovessels identified 84 significantly regulated proteins. Top three pathways significantly altered between low vs. high CAA cerebrovessels included TCA Cycle II, Oxidative phosphorylation and mitochondrial dysfunction. Notably, high CAA cases included more advanced AD pathology thus cerebrovascular effects may be driven by the severity of amyloid and Tangle pathology. These descriptive proteomic changes provide novel insights to explain the age-related and AD-related cerebrovascular changes contributing to AD pathogenesis. Particularly, disturbances in energy bioenergetics and mitochondrial biology rank among the top AD pathways altered in cerebrovessels. Targeting these failed mechanisms in endothelia and mural cells may provide novel disease modifying targets for developing therapeutic strategies against cerebrovascular deterioration and promoting cerebral perfusion in AD. Our future work will focus on interrogating and validating these novel targets and pathways and their functional significance.

Neighborhood Socioeconomic Resources and Crime-Related Psychosocial Hazards, Stroke Risk, and Cognition in Older Adults

Living in neighborhoods with lower incomes, lower education/occupational levels, and/or higher crime increases one’s risk of developing chronic health problems including cardiovascular disease risk factors and stroke. These cardiovascular health problems are known to contribute to cognitive decline and dementia. The purpose of this study was to determine the association of neighborhood socioeconomic resources and crime-related psychosocial hazards on stroke risk and cognition, hypothesizing that cardiovascular health would mediate any relationship between the neighborhood-level environment and cognition. The study evaluated 121 non-demented Chicago-area adults (~67 years; 40% non-Latino White) for cardiovascular health problems using the Framingham Stroke Risk Profile 10-year risk of stroke (FSRP-10). The cognitive domains that were tested included memory, executive functioning, and attention/information processing. Neighborhood socioeconomic resources were quantified at the census tract level (income, education, and occupation); crime-related psychosocial hazards were quantified at the point level. Structural equation modeling (SEM) did not show that the FSRP-10 mediated the relationship between neighborhood characteristics and domain-specific cognition. The SEM results did suggest that higher crime rates were associated with a higher FSRP-10 (β(105) = 2.38, p = 0.03) and that higher FSRP-10 is associated with reduced attention/information processing performance (β(105) = −0.04, p = 0.02) after accounting for neighborhood socioeconomic resources. Clinicians may wish to query not only individual but also neighborhood-level health when considering cognition.

Effects of White Matter Hyperintensities on Verbal Fluency in Healthy Older Adults and MCI/AD

BACKGROUND

White matter hyperintensities (WMHs) are markers for cerebrovascular pathology, which are frequently seen in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Verbal fluency is often impaired especially in AD, but little research has been conducted concerning the specific effects of WMH on verbal fluency in MCI and AD.

OBJECTIVE

Our aim was to examine the relationship between WMH and verbal fluency in healthy old age and pathological aging (MCI/AD) using quantified MRI data.

METHODS

Measures for semantic and phonemic fluency as well as quantified MRI imaging data from a sample of 42 cognitively healthy older adults and 44 patients with MCI/AD (total n = 86) were utilized. Analyses were performed both using the total sample that contained seven left-handed/ambidextrous participants, as well with a sample containing only right-handed participants (n = 79) in order to guard against possible confounding effects regarding language lateralization.

RESULTS

After controlling for age and education and adjusting for multiple correction, WMH in the bilateral frontal and parieto-occipital areas as well as the right temporal area were associated with semantic fluency in cognitively healthy and MCI/AD patients but only in the models containing solely right-handed participants.

CONCLUSION

The results indicate that white matter pathology in both frontal and parieto-occipital cerebral areas may have associations with impaired semantic fluency in right-handed older adults. However, elevated levels of WMH do not seem to be associated with cumulative effects on verbal fluency impairment in patients with MCI or AD. Further studies on the subject are needed.

Blood-brain barrier disruption in atrial fibrillation: a potential contributor to the increased risk of dementia and worsening of stroke outcomes?

Atrial fibrillation (AF) has become one of the most significant health problems worldwide, warranting urgent answers to currently pending questions on the effects of AF on brain function. Recent evidence has emerged to show an association between AF and an increased risk of developing dementia and worsening of stroke outcomes. A healthy brain is protected by the blood–brain barrier (BBB), which is formed by the endothelial cells that line cerebral capillaries. These endothelial cells are continuously exposed to shear stress (the frictional force generated by blood flow), which affects endothelial cell structure and function. Flow disturbances as experienced during AF can disrupt the BBB and leave the brain vulnerable to damage. Investigating the plausible mechanisms in detail, linking AF to cerebrovascular damage is difficult in humans, leading to paucity of available clinical data. Here, we discuss the available evidence for BBB disruption during AF due to altered cerebral blood flow, and how this may contribute to an increased risk of dementia and worsening of stroke outcomes.

Type 2 Diabetes and Cognitive Status in the Health and Retirement Study: A Mendelian Randomization Approach

Background

Type 2 diabetes mellitus (T2DM) and dementia are leading causes of mortality and disability in the US. T2DM has been associated with dementia; however, causality has not been clearly established. This study tested inferred causality between T2DM and dementia status using a Mendelian randomization approach.

Methods

Participants (50+ years) from the 2010 wave of the Health and Retirement Study of European or African genetic ancestry were included (n = 10,322). History of T2DM was self-reported. Cognitive status (dementia, cognitive impairment non-dementia, or normal cognition) was defined from clinically validated cognitive assessments. Cumulative genetic risk for T2DM was determined using a polygenic score calculated from a European ancestry T2DM genome-wide association study by Xue et al. (2018). All models were adjusted for age, sex, education, APOE-ε4 carrier status, and genetic principal components. Multivariable logistic regression was used to test the association between cumulative genetic risk for T2DM and cognitive status. To test inferred causality using Mendelian randomization, we used the inverse variance method.

Results

Among included participants, 20.9% had T2DM and 20.7% had dementia or cognitive impairment. Among European ancestry participants, T2DM was associated with 1.66 times odds of cognitive impairment non-dementia (95% confidence interval: 1.55–1.77) relative to normal cognition. A one standard deviation increase in cumulative genetic risk for T2DM was associated with 1.30 times higher odds of T2DM (95% confidence interval: 1.10–1.52). Cumulative genetic risk for T2DM was not associated with dementia status or cognitive-impaired non-dementia in either ancestry (P > 0.05); lack of association here is an important assumption of Mendelian randomization. Using Mendelian randomization, we did not observe evidence for an inferred causal association between T2DM and cognitive impairment (odds ratio: 1.04; 95% confidence interval: 0.90–1.21).

Discussion

Consistent with prior research, T2DM was associated with cognitive status. Prevention of T2DM and cognitive decline are both critical for public health, however, this study does not provide evidence that T2DM is causally related to impaired cognition. Additional studies in other ancestries, larger sample sizes, and longitudinal studies are needed to confirm these results.

Exposure to air pollution and cognitive impairment risk: a meta-analysis of longitudinal cohort studies with dose-response analysis

Background

We conducted a meta-analysis to explore the relationship between exposure to air pollution and the risk of cognitive impairment of longitudinal cohort studies.

Methods

PubMed, Web of Science and Wan Fang databases were searched for relevant articles of longitudinal cohort studies published between January 1950 and September 2019. The pooled relative ratio (RR) and 95% confidence interval (CI) were calculated using the random effect model.

Results

Ten articles involving 519 247 cases among 12 523 553 participants were included in this meta-analysis. The pooled RR of cognitive impairment per 5 μg/m³ increments in exposure to particulate matter ≤2.5 μm (PM_2.5) was 1.08 (95% CI = 1.03, 1.13; I²  = 82.2%; P_{heterogeneity} <0.001). No association was found between nitrogen dioxide/nitrogen oxide (NO₂/NO_x) and ozone (O₃) and cognitive impairment. For PM_2.5 exposure, in subgroup analysis, the above-mentioned significant positive association was found among studies conducted in population (RR _{p er 5 μg/m} ³ = 1.05; 95% CI = 1.01,1.09; I²  = 57.4%; P_{heterogeneity}  = 0.016), in North America (RR _{per 5 μg/m} ³  = 1.13; 95% CI = 1.01,1.26; I²  = 86.7%; P_{heterogeneity} <0.001) and with follow-up duration >10 years (RR _{p er 5 μg/m} ³  = 1.10; 95% CI = 1.03,1.17; I²  = 86.3%; P_{heterogeneity} <0.001).

Conclusions

This meta-analysis suggests that exposure to PM_2.5 might increase the risk of cognitive impairment.

Statin exposure and the risk of dementia in individuals with hypercholesterolaemia

OBJECTIVES

This study aimed to examine the association between statin exposure and dementia risk in individuals with hypercholesterolaemia using data from the NHIS-HEALS database between 2002 and 2015.

METHODS

Subjects were classified into statin exposure and statin nonexposure groups according to medication possession ratio. Dementia was defined as those with primary diagnostic dementia codes such as F00-F03, G30, G31.1, G31.9 or G31.82. Cox proportional hazards regression models were adopted after stepwise adjustment for confounders to investigate the prospective association between statin exposure and dementia risk.

RESULTS

During the follow-up period (median follow-up 11.7 years), 711 cases of dementia occurred, accounting for 11.5% of the total study population (statin exposure group, 8.2%; statin nonexposure group, 12.9%). Compared to the statin nonexposure group, fully adjusted hazard ratios (HRs) (95% confidence intervals [CIs]) for overall dementia in the statin exposure group were 0.63 (0.43-0.91) and 0.62 (0.50-0.78) in men and women, respectively. Compared to the statin nonexposure group, the HRs (95% CIs) for Alzheimer's disease and related dementia, vascular dementia and other types of dementia in the statin exposure group were 0.54 (0.32-0.91), 2.45 (0.69-8.68) and 0.59 (0.32-1.07), respectively, in men and 0.53 (0.38-0.73), 1.29 (0.42-3.96) and 0.70 (0.51-0.96), respectively, in women.

CONCLUSIONS

Hypercholesterolaemic individuals exposed to statin had a lower risk of overall dementia and Alzheimer's disease and related dementia in both sexes, and a lower risk of other types of dementia in women, than subjects who were not exposed to statins.

Effects of Blood Pressure on Cognitive Performance in Aging: A Systematic Review

INTRODUCTION

Cognitive functions play a crucial role in daily functioning. Unfortunately, some cognitive abilities decline in the process of healthy aging. An increasing body of evidence has highlighted the role of lifestyle habits and cardiovascular diseases, such as high blood pressure, in increasing the risk of cognitive decline. Surprisingly, although hypertension is a modifiable risk factor for cerebrovascular damage, the role of hypertension on cognitive impairment development is not still clear. Several key questions remain unresolved, and there are many inconsistent results in studies considering this topic. This review is aimed to systematically analyze the results found by the studies that investigated whether high blood pressure, in both hypertensive and healthy people, is related to cognitive performance. Furthermore, it points to evaluate the role of age in this relationship. Method: The review process was conducted according to the PRISMA statement. Restrictions were made, selecting the studies in English and published in peer-review journals, including at least one cognitive measure and blood pressure measurement. Studies that included participants with medical conditions, dementia, psychiatric disorders, strokes, and brain injury were excluded. Cross-sectional and longitudinal studies were analyzed separately. Finally, blood pressure measured at young life (18-39 years), midlife (age 40-64 years), elderly (65-74 years), and old age (≥75 years) were considered. Results: The review allows 68 studies to be selected, which include 154,935 participants. The results provided evidence of an adverse effect of exposure to high blood pressure on cognitive performance. High blood pressure in midlife was linked with poorer cognitive functioning; this evidence was found in cross-sectional and longitudinal studies. However, this association declines with increasing age and tends to become inconsistent. In older people, the relationship between blood pressure and cognitive performance is non-linear, highlighting a beneficial effect of high blood pressure on cognition. Conclusions: Despite some limitations, this review showed that cardiovascular and neuro-cognitive systems do not operate in isolation, but they are related. Blood pressure can be considered an early biomarker of cognitive impairment, and the necessity of early blood pressure measurement and control was underlined.

Therapeutic Potential of Porcine Liver Decomposition Product: New Insights and Perspectives for Microglia-Mediated Neuroinflammation in Neurodegenerative Diseases

It is widely accepted that microglia-mediated inflammation contributes to the progression of neurodegenerative diseases; however, the precise mechanisms through which these cells contribute remain to be elucidated. Microglia, as the primary immune effector cells of the brain, play key roles in maintaining central nervous system (CNS) homeostasis. Microglia are located throughout the brain and spinal cord and may account for up to 15% of all cells in the brain. Activated microglia express pro-inflammatory cytokines that act on the surrounding brain and spinal cord. Microglia may also play a detrimental effect on nerve cells when they gain a chronic inflammatory function and promote neuropathologies. A key feature of microglia is its rapid morphological change upon activation, characterized by the retraction of numerous fine processes and the gradual acquisition of amoeba-like shapes. These morphological changes are also accompanied by the expression and secretion of inflammatory molecules, including cytokines, chemokines, and lipid mediators that promote systemic inflammation during neurodegeneration. This may be considered a protective response intended to limit further injury and initiate repair processes. We previously reported that porcine liver decomposition product (PLDP) induces a significant increase in the Hasegawa’s Dementia Scale-Revised (HDS-R) score and the Wechsler Memory Scale (WMS) in a randomized, double-blind, placebo-controlled study in healthy humans. In addition, the oral administration of porcine liver decomposition product enhanced visual memory and delayed recall in healthy adults. We believe that PLDP is a functional food that aids cognitive function. In this review, we provide a critical assessment of recent reports of lysophospholipids derived from PLDP, a rich source of phospholipids. We also highlight some recent findings regarding bidirectional interactions between lysophospholipids and microglia and age-related neurodegenerative diseases such as dementia and Alzheimer’s disease.

Midlife Hypertension and Alzheimer's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Hypertension is an established risk factor for stroke and vascular dementia but recent meta-analyses examining the association between Alzheimer's disease (AD) and hypertension have found no significant association. These meta-analyses included short term studies starting in late life which may have obscured the real effect of midlife hypertension.

OBJECTIVE

To examine the association of AD with midlife hypertension, by including only studies with a sufficiently long follow up duration.

METHODS

Relevant studies were found by searches of MEDLINE, EMBASE, and PubMed. Study outcomes were grouped by measures of blood pressure and definition of hypertension (e.g., systolic hypertension > 140 mmHg or > 160 mmHg). We assessed pooled effect estimates using random effects models and heterogeneity of pooled estimates through the I2 statistic.

RESULTS

Literature search found 3,426 publications of which 7 were eligible studies. There was a significant association between systolic hypertension (>160 mm Hg) and AD (HR 1.25, 95CI 1.06 - 1.47, p = 0.0065). Similarly, for systolic hypertension > 140 mm Hg, there was a smaller but still significant association (HR 1.18, 95CI 1.02 - 1.35, p = 0.021). For diastolic hypertension, all four studies found no significant associations between diastolic hypertension and AD, and these data could not be pooled due to heterogeneity in reporting.

CONCLUSIONS

Our study found that midlife stage 1 and stage 2 systolic hypertension is associated with increased risk of AD by 18 and 25%, respectively, although no association was found for diastolic hypertension. It is likely that assertive control of systolic hypertension starting in midlife is important to preventing AD.

Carotid Atherosclerosis and Cognitive Function in a General Population Aged 63-65 Years: Data from the Akershus Cardiac Examination (ACE) 1950 Study

BACKGROUND

Studies on the relationship between carotid atherosclerosis and cognitive function in subjects from the general population are few and results have been inconsistent.

OBJECTIVE

We aimed to investigate the association between carotid atherosclerotic burden and cognitive function in a cross-sectional analysis of a population-based cohort aged 63-65 years.

METHODS

All habitants born in 1950 from Akershus County, Norway were invited to participate. A linear regression model was used to assess the association between carotid atherosclerosis and cognitive function. We used carotid plaque score as a measure of carotid atherosclerotic burden and the Montreal Cognitive Assessment (MoCA) for global cognitive function.

RESULTS

We analyzed 3,413 individuals aged 63-65 with mean MoCA score 25.3±2.9 and 87% visible carotid plaques. We found a negative correlation between carotid plaque score and MoCA score (r = -0.14, p < 0.001), but this association was lost in multivariable analysis. In contrast, diameter or area of the thickest plaque was independently associated with MoCA score. Lower educational level, male sex, current smoking, and diabetes were also associated with lower MoCA score in multivariable analysis.

CONCLUSION

Carotid atherosclerotic burden was, unlike other measures of advanced carotid atherosclerosis, not independently associated with global cognitive function.

Can cardiovascular risk management be improved by shared care with general practice to prevent cognitive decline following stroke/TIA? A feasibility randomised controlled trial (SERVED memory)

Background

Cognitive impairment and dementia following cerebrovascular disease are increasingly common in the UK. One potential strategy to prevent post-stroke cognitive decline is multimodal vascular risk factor management. However, its efficacy remains uncertain and its application in vulnerable patients with incident cerebrovascular disease and early cognitive impairment has not been assessed.

The primary aim of this study was to assess the feasibility of recruitment and retention of patients with early cognitive impairment post-stroke or transient ischaemic attack (TIA) to a trial of enhanced vascular risk factor management combining primary and secondary care.

Methods

In this single centre, open label trial adults with a recent stroke or TIA and mild cognitive impairment (MCI) were randomised 1:1 to a three-monthly multimodal vascular risk factor intervention jointly delivered by the trial team and General Practitioner (GP), or control (defined as usual care from the GP). Chosen risk factors were blood pressure (BP), total cholesterol, blood glucose (HbA1C) in those with diabetes, and heart rate and adequacy of anticoagulation in those with atrial fibrillation (AF). Similar patients with normal cognition were enrolled in an embedded observational cohort and also received usual care from the GP. Repeat cognitive screening was undertaken in all participants after 12 months.

Results

Seventy three participants were recruited to the randomised trial and 94 to the observational cohort (21.8% of those screened). From the randomised trial 35/73 (47.9%) dropped out before final follow-up. In all groups guideline based rates of risk factor control were mostly poor at baseline and did not significantly improve during follow-up. The observational cohort demonstrated greater decline in cognitive test scores at 12 months, with no difference between the randomised groups.

Conclusions

Recruitment to such a study was feasible, but retention of participants was difficult and generally poor rates of risk factor control suggested insufficient application of the intervention. Consequently, successful scaling up of the trial would require protocol changes with less reliance on primary care services. Any future trial should include participants with normal cognition post-stroke as they may be at greatest risk of cognitive decline.

Trial registration

ISRCTN, ISRCTN42688361. Registered 16 April 2015.

Brain angiotensin II and angiotensin IV receptors as potential Alzheimer's disease therapeutic targets

Alzheimer's disease (AD) is a neurodegenerative disorder that is multifactorial in nature. Yet, despite being the most common form of dementia in the elderly, AD's primary cause remains unknown. As such, there is currently little to offer AD patients as the vast majority of recently tested therapies have either failed in well-controlled clinical trials or inadequately treat AD. Recently, emerging preclinical and clinical evidence has associated the brain renin angiotensin system (RAS) to AD pathology. Accordingly, various components of the brain RAS were shown to be altered in AD patients and mouse models, including the angiotensin II type 1 (AT1R), angiotensin IV receptor (AT4R), and Mas receptors. Collectively, the changes observed within the RAS have been proposed to contribute to many of the neuropathological hallmarks of AD, including the neuronal, cognitive, and vascular dysfunctions. Accumulating evidence has additionally identified antihypertensive medications targeting the RAS, particularly angiotensin receptor blockers (ARBs) and angiotensin-converting enzyme inhibitors (ACEIs), to delay AD onset and progression. In this review, we will discuss the emergence of the RAS's involvement in AD and highlight putative mechanisms of action underlying ARB's beneficial effects that may explain their ability to modify the risk of developing AD or AD progression. The RAS may provide novel molecular targets for recovering memory pathways, cerebrovascular function, and other pathological landmarks of AD.

Vitamin B6, B12, Asam Folat, Tekanan Darah dan Demensia pada Lanjut Usia

Background: Dementia is a multifactorial disease due to genetic and environmental influences. Lack of intake of vitamins B6, B12, folic acid and blood pressure are one of the environmental factors that cause dementia.Objective: To analyze the relationship between the adequacy of vitamins B6, B12, folic acid and blood pressure with dementia in the elderlyMethod: This research was a cross sectional study, which was carried out in Tulungagung Regency. The sampling technique was cluster random sampling and a sample size of 100 elderly from 7 elderly Posyandu in Tulungagung Regency, with independent variables such as adequacy of vitamin B6, B12, folic acid and blood pressure, while the dependent variable was dementia. Data were analyzed with chi square testResults: Respondents in this study were generally aged 60-74 years (70.0%), women (48.0%), were educated in elementary / junior high school (60.0%) and did not work (69.0%). Most respondents have insufficient vitamin B6, B12 and folic acid in the less category, with percentages of 57.0%, 54% and 64%, respectively. There was an association between the adequacy of vitamins B6, B12 and folic acid with dementia in the elderly (OR=2.302; 95% CI=1.011-5.241; p=0.045; OR=2.397; 95% CI=1.060-5.422; p=0.034; OR=2.516; 95% CI=1.015-6.238; p=0.043). Blood pressure is associated with dementia in the elderly (OR=3.000; 95% CI=1.288-6.988; p=0.010). The average consumption of vitamin B6, B12 and folic acid in the normal group was higher than the dementia group, with a difference of 0.16 ± 0.04 mg, 0.54 ± 0.05 mcg and 65.89 ± 4.95 respectively mcgConclusionABSTRAKLatar Belakang: Demensia merupakan penyakit multifaktorial karena pengaruh genetik dan lingkungan. Minimnya asupan vitamin B6, B12, asam folat dan tekanan darah menjadi salah satu faktor lingkungan yang menyebabkan demensia.Tujuan:  Tujuan penelitian ini adalah menganalisis hubungan antara kecukupan vitamin B6, B12, asam folat dan tekanan darah dengan demensia pada lanjut usiaMetode: Penelitian ini berupa penelitian cross sectional, yang dilakukan di Kabupaten Tulungagung. Teknik sampling dengan cluster random sampling dan besar sampel 100 lansia dari 7 posyandu lansia di Kabupaten Tulungagung, dengan variabel bebas berupa kecukupan vitamin B6, B12, asam folat dan tekanan darah, sedangkan variabel terikatnya adalah demensia. Data dianalisis dengan uji chi squareHasil: Responden penelitian ini umumnya berusia 60-74 tahun (70,0 %), wanita (48,0 %), berpendidikan terakhir SD/SMP (60,0 %) dan tidak bekerja (69,0 %). Kebanyakan responden memiliki kecukupan vitamin B6, B12 dan asam folat dalam kategori kurang, dengan persentase masing-masing  57,0 %, 54 % dan 64 %. Ditemukan hubungan antara kecukupan vitamin B6, B12 dan asam folat dengan demensia pada lanjut usia (OR=2,302, 95% CI=1,011-5,241, p=0,045; OR=2,397, 95% CI=1,060-5,422, p=0,034; OR=2,516,95% CI=1,015-6,238, p=0,043). Tekanan darah berhubungan dengan demensia pada lanjut usia (OR=3,000,95% CI=1,288-6,988,p=0,010). Rata-rata konsumsi vitamin B6, B12 dan asam folat kelompok normal lebih tinggi dibandingkan kelompok demensia, dengan selisih masing-masing sebesar 0,16±0,04 mg, 0,54±0,05 mcg dan 65,89 ±4,95 mcg.Kesimpulan: Terdapat hubungan antara kecukupan vitamin B6, B12, asam folat dan tekanan darah dengan demensia pada lanjut usia. 

Hemodynamic Instability in Heart Failure Intensifies Age-Dependent Cognitive Decline

This review attempts to examine two key elements in the evolution of cognitive impairment in the elderly who develop heart failure. First, major left side heart parts can structurally and functionally deteriorate from aging wear and tear to provoke hemodynamic instability where heart failure worsens or is initiated; second, heart failure is a major inducer of cognitive impairment and Alzheimer's disease in the elderly. In heart failure, when the left ventricular myocardium of an elderly person does not properly contract, it cannot pump out adequate blood to the brain, raising the risk of cognitive impairment due to the intensification of chronic brain hypoperfusion. Chronic brain hypoperfusion originates from chronically reduced cardiac output which progresses as heart failure worsens. Other left ventricular heart parts, including atrium, valves, myocardium, and aorta can contribute to the physiological shortfall of cardiac output. It follows that hemodynamic instability and perfusion changes occurring from the aging heart's blood pumping deficiency will, in time, damage vulnerable brain cells linked to specific cognitive regulatory sites, diminishing neuronal energy metabolism to a level where progressive cognitive impairment is the outcome. Could cognitive impairment progress be reversed with a heart transplant? Evidence is presented detailing the errant hemodynamic pathways leading to cognitive impairment during aging as an offshoot of inefficient structural and functional heart parts and their contribution to heart failure.

The Effects of Exercise Training on the Brain-Derived Neurotrophic Factor (BDNF) in the Patients with Type 2 Diabetes: A Systematic Review of the Randomized Controlled Trials

Purpose

Glucose dysregulation is one of the distinctive features of type 2 diabetes that is associated with an increased risk of cognitive impairment and dementia. The low concentrations of brain-derived neurotrophic factor (BDNF) are reported in people with insulin resistance, metabolic syndrome, and type 2 diabetes. BDNF can be increased by an adjustment in lifestyle including caloric restriction and exercise training. Studies have reported controversial findings about physical activity and its association with BDNF, but there is no comprehensive conclusions on this issue. The aim of this study was to systematically review the effects of exercise training on BDNF levels in patients with type 2 diabetes.

Methods

The electronic databases of Embase, Pedro, PubMed, Medline, Cochrane Library, as well as the Google Scholar search engine were used to obtain the related data about the role of exercise training on BDNF levels in patients with type 2 diabetes. The search period was set from inception to August 2019. Keywords of "exercise", "training", "physical activity", "brain-derived neurotrophic factor", "type 2 diabetes", and "randomized clinical trials", were used in persian and English. The PEDro scale was used to evaluate the quality of the included articles. Results. Finally, 11 articles (four human and seven animal articles) with medium to high quality were included in the study which 5 articles reported elevation (one human and four animal articles), 4 articles reported a reduction (one human and three animal articles), and 2 articles reported no changes (both of them in human articles) in BDNF level following the exercise training.

Conclusion

Decreased energy intake and increased energy expenditure through exercise training may modulate BDNF levels in patients with type 2 diabetes.

Multiple Causes of Dementia as Engineered Senescence

All traumas—cranial, cardiovascular, hormone, viral, bacterial, fungi, parasites, misfolded protein, genetic, behavior, environmental and medication—affect the brain. This paper itemizes studies showing the many different causes of dementia including Alzheimer’s disease. Causes interact with each other, act sequentially by preparing the optimal conditions for its successor, initiate other diseases, allow for other traumas to accumulate and degrade protective features of the brain. Since such age-related cognitive impairment is not exclusively a human attribute there might be support for an evolutionary theory of dementia. Relying on theories of antagonistic pleiotropy and polymorphism, the brain has been designed to sequester trauma. Because of increased longevity, the short-term tactic of sequestering trauma becomes a long-term liability. We are engineered to sequester these insults until a tipping point is reached. Dementia is an evolutionary trade-off for longevity. We cannot cure dementia without understanding the overall biology of aging.

Association Between Atrial Fibrillation and Cognitive Impairment in Individuals With Prior Stroke: A Meta-Analysis and Meta-Regression Analysis

Background and Purpose- Atrial fibrillation (AF) is the most common chronic arrhythmia. Dementia and cognitive impairment (CI) are major burdens to public health. The prevalence of all 3 entities is projected to increase due to population aging. Previous reports have linked AF with a higher risk of CI and dementia in patients without prior stroke. Stroke is known to increase the risk for dementia and CI. It is unclear if AF in patients with history of stroke can further increase the risk for dementia or CI. Our purpose was to evaluate the impact of AF on risk for dementia or CI among patients with history of stroke. Methods- Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines were followed. Pubmed, Scopus, and Cochrane central were searched. The outcomes of interest were dementia, CI, and the composite end point of dementia or CI. A random-effect model meta-analysis was performed. Meta-regression analysis was also performed. Publication bias was assessed with the Egger test and with funnel plots. Results- Fourteen studies and 14 360 patients (1363 with AF) were included in the meta-analysis. In the meta-analysis of adjusted odds ratio, AF was associated with increased risk of CI (odds ratio, 1.60 [95% CI, 1.20-2.14]), dementia (odds ratio, 3.11 [95% CI, 2.05-4.73]), and the composite end point of CI or dementia (odds ratio, 2.26 [95% CI, 1.61-3.19]). The heterogeneity for the composite end point of dementia or CI was moderate (adjusted analysis). The heterogeneity for the analysis of the end point of CI only was substantial in the unadjusted analysis and moderate in the adjusted analysis. The heterogeneity for the end point of dementia only was moderate in the unadjusted analysis and zero in the adjusted analysis. Conclusions- Our results indicate that an association between AF and CI or dementia is patients with prior strokes is possible given the persistent positive associations we noticed in the unadjusted and adjusted analyses. The heterogeneity levels limit the certainty of our findings.

The Cognitive Effects of Statins are Modified by Age

To reveal new insights into statin cognitive effects, we performed an observational study on a population-based sample of 245,731 control and 55,114 statin-taking individuals from the UK Biobank. Cognitive performance in terms of reaction time, working memory and fluid intelligence was analysed at baseline and two follow-ups (within 5-10 years). Subjects were classified depending on age (up to 65 and over 65 years) and treatment duration (1-4 years, 5-10 years and over 10 years). Data were adjusted for health- and cognition-related covariates. Subjects generally improved in test performance with repeated assessment and middle-aged persons performed better than older persons. The effect of statin use differed considerably between the two age groups, with a beneficial effect on reaction time in older persons and fluid intelligence in both age groups, and a negative effect on working memory in younger subjects. Our analysis suggests a modulatory impact of age on the cognitive side effects of statins, revealing a possible reason for profoundly inconsistent findings on statin-related cognitive effects in the literature. The study highlights the importance of characterising modifiers of statin effects to improve knowledge and shape guidelines for clinicians when prescribing statins and evaluating their side effects in patients.