Adverse vascular risk is related to cognitive decline in older adults

A review of the application of exercise intervention on improving cognition in patients with Alzheimer's disease: mechanisms and clinical studies

Alzheimer's disease (AD) is the most common form of dementia, leading to sustained cognitive decline. An increasing number of studies suggest that exercise is an effective strategy to promote the improvement of cognition in AD. Mechanisms of the benefits of exercise intervention on cognitive function may include modulation of vascular factors by affecting cardiovascular risk factors, regulating cardiorespiratory health, and enhancing cerebral blood flow. Exercise also promotes neurogenesis by stimulating neurotrophic factors, affecting neuroplasticity in the brain. Additionally, regular exercise improves the neuropathological characteristics of AD by improving mitochondrial function, and the brain redox status. More and more attention has been paid to the effect of Aβ and tau pathology as well as sleep disorders on cognitive function in persons diagnosed with AD. Besides, there are various forms of exercise intervention in cognitive improvement in patients with AD, including aerobic exercise, resistance exercise, and multi-component exercise. Consequently, the purpose of this review is to summarize the findings of the mechanisms of exercise intervention on cognitive function in patients with AD, and also discuss the application of different exercise interventions in cognitive impairment in AD to provide a theoretical basis and reference for the selection of exercise intervention in cognitive rehabilitation in AD.

Alzheimer's disease: a comprehensive review of epidemiology, risk factors, symptoms diagnosis, management, caregiving, advanced treatments and associated challenges

Background

Alzheimer's disease (AD) is a chronic, progressive neurodegenerative disorder characterized by cognitive decline, memory loss, and impaired reasoning. It is the leading cause of dementia in older adults, marked by the pathological accumulation of amyloid-beta plaques and neurofibrillary tangles. These pathological changes lead to widespread neuronal damage, significantly impacting daily functioning and quality of life.

Objective

This comprehensive review aims to explore various aspects of Alzheimer's disease, including its epidemiology, risk factors, clinical presentation, diagnostic advancements, management strategies, caregiving challenges, and emerging therapeutic interventions.

Methods

A systematic literature review was conducted across multiple electronic databases, including PubMed, MEDLINE, Cochrane Library, and Scopus, from their inception to May 2024. The search strategy incorporated a combination of keywords and Medical Subject Headings (MeSH) terms such as "Alzheimer's disease," "epidemiology," "risk factors," "symptoms," "diagnosis," "management," "caregiving," "treatment," and "novel therapies." Boolean operators (AND, OR) were used to refine the search, ensuring a comprehensive analysis of the existing literature on Alzheimer's disease.

Results

AD is significantly influenced by genetic predispositions, such as the apolipoprotein E (APOE) ε4 allele, along with modifiable environmental factors like diet, physical activity, and cognitive engagement. Diagnostic approaches have evolved with advances in neuroimaging techniques (MRI, PET), and biomarker analysis, allowing for earlier detection and intervention. The National Institute on Aging and the Alzheimer's Association have updated diagnostic criteria to include biomarker data, enhancing early diagnosis.

Conclusion

The management of AD includes pharmacological treatments, such as cholinesterase inhibitors and NMDA receptor antagonists, which provide symptomatic relief but do not slow disease progression. Emerging therapies, including amyloid-beta and tau-targeting treatments, gene therapy, and immunotherapy, offer potential for disease modification. The critical role of caregivers is underscored, as they face considerable emotional, physical, and financial burdens. Support programs, communication strategies, and educational interventions are essential for improving caregiving outcomes. While significant advancements have been made in understanding and managing AD, ongoing research is necessary to identify new therapeutic targets and enhance diagnostic and treatment strategies. A holistic approach, integrating clinical, genetic, and environmental factors, is essential for addressing the multifaceted challenges of Alzheimer's disease and improving outcomes for both patients and caregivers.

The Relationship between Framingham Stroke Risk Profile on Incident Dementia and Alzheimer's Disease: A 40-Year Follow-Up Study Highlighting Female Vulnerability

OBJECTIVE

Sex differences in the association between cardiovascular risk factors and the incident all-cause dementia and the subtype Alzheimer's disease (AD) risk are unclear.

METHODS

Framingham Heart Study (FHS) participants (n = 4,171, 54% women, aged 55 to 69 years) were included at baseline and followed up to 40 years. The Framingham Stroke Risk Profile (FSRP) was dichotomized into 2 levels (cutoff: 75th percentile of the FSRP z-scores). Cause-specific hazard models, with death as a competing event, and restricted mean survival time (RMST) model were used to analyze the association between FSRP levels and incident all-cause dementia and AD. Interactions between FSRP and sex were estimated, followed by a sex-stratified analysis to examine the sex modification effect.

RESULTS

High FSRP was significantly associated with all-cause dementia (hazard ratio [HR] = 1.25, robust 95% confidence interval [CI] = 1.21 to 1.29, p < 0.001) and AD (HR = 1.58, robust 95% CI = 1.57 to 1.59, p < 0.001) in cause-specific hazard models. High FSRP was significantly associated with incident dementia (HR = 2.81, robust 95% CI = 2.75 to 2.87, p < 0.001) and AD (HR = 2.96, robust 95% CI = 2.36 to 3.71, p < 0.001) in women, but not in men. Results were consistent in the RMST models. Current diabetes and high systolic blood pressure as FSRP components were significantly associated with dementia and AD in women but not in men.

INTERPRETATION

High FSRP in mid- to early late life is a critical risk factor for all-cause dementia and AD, particularly in women. Sex-specific interventions and further research to elucidate underlying mechanisms are warranted. ANN NEUROL 2024;96:1124-1134.

Arterial stiffness measured by pulse wave velocity correlated with cognitive decline in hypertensive individuals: a systematic review

BACKGROUND

Arterial stiffness is a degenerative modification in the arterial wall that significantly affects normal aging. Arterial hypertension is a major risk factor for cerebrovascular impairment. Pulse wave velocity (PWV) is an established gold standard for measuring arterial stiffness. Studies demonstrated that individuals with elevated blood pressure (BP) and PWV are more likely to experience worse cognitive decline compared to those with either condition alone. The aim of this review is to explore the clinical importance of arterial stiffness for cognitive function in older adults with hypertension.

METHODS

The systematic review was reported following the PRISMA 2020 guidelines and Cochrane protocol and was registered in NIHR PROSPERO. PubMed, Embase, Web of Science, CINAHL, and Cochrane databases were searched for relevant publications up to December 2022. Articles were filtered by age and type of study and only those including a sample size of at least 500 individuals were selected. Screening of abstracts and full-text review of selected articles were carried out through Covidence.

RESULTS

The full-text review included a total of 434 articles. Twenty-eight prospective studies have met the inclusion criteria. Selected studies used PWV as the main measurement of stiffness: 24 used carotid-femoral, 2 used brachial-ankle, 1 used aortic PWV, and 11 compared different measures. Studies demonstrated a strong association between increased BP and PWV with brain damage and cognitive deterioration among older adults. One study did not find an interaction with hypertension, while another study found that PWV but not BP was associated with cognitive decline. Few studies showed that the association between stiffness and cognitive outcomes was not significant after adjustment for BP. Several authors suggested that cognitive decline induced by stiff vasculature and hypertension benefited from antihypertensive therapy.

CONCLUSION

The results of this review demonstrated that arterial hypertension is an important factor linking arterial stiffness to cognitive health in older individuals. BP plays a crucial role in brain integrity, whereas PWV was shown to be a strong measure associated with cognitive decline. Together, they can lead to disabling cognitive outcomes. Early screening of stiffness, BP control, and compliance with treatment are essential for cerebrovascular disease prevention.

TRIAL REGISTRATION

NIHR PROSPERO registry ID: CRD42022379887 .

Comparative Study of Risk Factors Associated with Normal Cognition and Cognitive Impairment in Rural West Elderly Texans

Background

Alzheimer's disease (AD) is related to one or more chronic illnesses, which may develop cognitive decline and dementia. Cognitive impairment is increasing, and public health officials must address risk factors for AD to improve the health of rural West Texas communities.

Objective

The purpose of this study was to explore the sociodemographic and chronic disease risk factors related to cognitive impairment among elderly adults living in Cochran, Parmer, and Bailey counties in rural West Texas.

Methods

Statistical methods such as Pearson's chi-squared, proportion tests, univariate binary logistic regression, and a multivariable logistic regression were utilized to analyze data. SPSS software was used to detect the significant relationship between cognitive impairment and risk factors.

Results

Summary statistics were obtained for sociodemographic and chronic diseases by using cross-tabulation analysis and comparing the county respondents with proportion tests. A univariate binary logistic regression method was utilized and found that age group 60-69, anxiety, depression, diabetes, hypertension, and cardiovascular disease were significantly associated with cognitive impairment. Using a multivariable logistic regression approach, it was found that Bailey County (age group 60-69) had a higher likelihood (p = 0.002) of cognitive impairment than Parmer (p = 0.067) and Cochran counties (p = 0.064). The risk of females (p = 0.033) in Parmer County was 78.3% lower compared to males in developing AD.

Conclusions

Identifying significant risk factors for cognitive impairment are important in addressing issues of geographic variations and integrating such factors may guide relevant policy interventions to reduce cognitive impairment incidence in rural communities within West Texas.

Examining biopsychosocial predictors of risk for cognitive impairment among a racially diverse sample of men who have sex with men living with HIV

Background

Cognitive decline among people living with HIV (PLWH) is growing concern as world populations become increasing older including higher proportions of PLWH. It is vitally important to understand psychosocial predictors of age-related cognitive decline men who have sex with men (MSM) living with HIV.

Objectives

The current study seeks to examine psychosocial risk factors the contribute to the risk of age-related cognitive impairment as measured by Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) score in a racially diverse sample of MSM living with HIV.

Design

The present analysis utilizes data from the baseline (n = 196) and 6-month follow-up (n = 135) time points of a longitudinal cohort study of PLWH.

Methods

Using a self-report survey, we examine the associations between psychosocial predictors (e.g. trauma, mental health, chronic pain, sleep disturbance, etc.) and risk of dementia using the CAIDE risk score. Analyses include linear and logistic regression.

Results

In adjusted model stress, chronic pain, Black racial identity, and having a sexual identity that is bisexual or another category are all positively associated with CAIDE scores. Childhood sexual abuse history was negatively associated with CAIDE scores indicating a protective effect. Sleep disorder has a positive association with CAIDE scores after adjusting for the baseline CAIDE scores.

Conclusion

These results indicate modifiable correlates of cognitive risk (stress and chronic pain). Interventions should seek to address these comorbid factors including the consideration of minority stress and stigma. Interventions should seek to reach Black and bisexual men living with HIV, including possible cultural tailoring to interventions and messaging. Lastly, future research should examine the impact of variation within childhood sexual abuse histories to better understand their association with cognitive impairment later in life. This may include considering the nature, severity, and potential treatment of trauma symptoms.

Relationship between Framingham Cardiovascular Risk Score and cognitive performance among ageing rural Indian participants: a cross-sectional analysis

OBJECTIVE

The burden of cardiovascular risk factors is increasing in India, which, in turn, can adversely impact cognition. Our objective was to examine the effect of cardiovascular risk factors measured by Framingham Risk Score (FRS) on cognitive performance among a cohort of healthy, ageing individuals (n=3609) aged ≥45 years from rural India.

DESIGN

A cross-sectional analysis.

SETTING

A rural community setting in southern India.

PARTICIPANTS

Healthy, ageing, dementia-free participants, aged 45 years and above, belonging to the villages of Srinivaspura (a rural community located around 100 km from Bangalore, India), were recruited.

PRIMARY OUTCOME MEASURES

Using a locally adapted, validated, computerised cognitive test battery, we assessed cognitive performance across multiple cognitive domains: attention, memory, language, executive functioning and visuospatial ability.

RESULTS

The median (IQR) age of the sample was 57 (50.65) and 50.5% were women. Multiple linear regression analysis showed that participants with higher FRS performed poorly in attention (visual attention (β=-0.018, p=0.041)), executive functioning (categorical fluency (β=-0.064, p<0.001)), visuospatial ability (form matching (β=-0.064, p<0.001) and visuospatial span (β=-0.020, p<0.001)), language (reading and sentence comprehension (β=-0.010, p=0.013), word comprehension (β=-0.021, p<0.001) and semantic association (β=-0.025, p<0.001)), and memory (episodic memory IR (β=-0.056, p<0.001), episodic memory DR (β=-0.076, p<0.001) and name-face association (β=-0.047, p<0.001)).

CONCLUSION

Increased cardiovascular risk as evidenced by FRS was associated with poorer cognitive performance in all cognitive domains among dementia-free middle-aged and older rural Indians. It is imperative to design and implement appropriate interventions (pharmacological and lifestyle-based) for cardiovascular risk reduction and thereby, prevent or mitigate accelerated cognitive impairment in ageing individuals.

Cardiovascular disease risk models and dementia or cognitive decline: a systematic review

Background

Health cognitive promotion and protection is a critical topic. With the world's aging population and rising life expectancy, there will be many people living with highly age-related dementia illnesses. Cardiovascular disease (CVD) and dementia share the same risk factors, such as unhealthy lifestyles and metabolic factors. These recognized risks associated with CVD and dementia frequently co-occur. CVD risk models may have a close association with dementia and cognitive decline. So, this systematic review aimed to determine whether CVD risk models were connected with dementia or cognitive decline and compare the predictive ability of various models.

Methods

PubMed, Web of Science, PsychINFO, Embase, Cochrane Library, CNKI, Sinomed, and WanFang were searched from 1 January 2014 until 16 February 2023. Only CVD risk models were included. We used the Newcastle-Ottawa scale (NOS) for the quality assessment of included cohort studies and the Agency for Healthcare Research and Quality (AHRQ) for cross-sectional studies. The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement's guidelines were followed in this systematic study.

Results

In all, 9,718 references were screened, of which 22 articles were included. A total of 15 CVD risk models were summarized. Except for the Cardiovascular Health in Ambulatory Care Research Team (CANHEART) health index, the other 14 CVD risk models were associated with dementia and cognitive decline. In comparison, different CVD risk models and domain-specific cognitive function correlation variation depended on cohort characteristics, risk models, cognitive function tests, and study designs. Moreover, it needed to be clarified when comparing the predicting performance of different CVD risk models.

Conclusion

It is significant for public health to improve disease risk prediction and prevention and mitigate the potential adverse effects of the heart on the brain. More cohort studies are warranted to prove the correlation between CVD risk models and cognitive function. Moreover, further studies are encouraged to compare the efficacy of CVD risk models in predicting cognitive disorders.

Impact of cardiovascular risk factors on the relationships of physical activity with mood and cognitive function in a diverse sample

Physical activity has well-known benefits for older adults' mood and cognitive functioning; however, it is not clear whether risk factors for cardiovascular disease (CVD) affect the relationships of physical activity with these health outcomes among diverse older adults. This study investigated the impact of CVD risk burden on the relationships among self-reported physical activity, mood, and cognitive functioning in a diverse sample of 62 adults age 45 and older. We found that higher physical activity was associated with better attention and verbal working memory at lower CVD risk, but with worse attention and verbal working memory at higher CVD risk levels. Thus, higher CVD risk might limit the effectiveness of exercise interventions for mood and cognitive functioning. Future studies are needed to further clarify individual differences that impact the relationships among physical activity, CVD risk, and cognitive outcomes.

Association between daily sleep duration and the risk of incident dementia according to the presence or absence of diseases among older Japanese individuals in the New Integrated Suburban Seniority Investigation (NISSIN) project

OBJECTIVE

This study aimed to investigate the association between daily sleep duration and incident dementia among physically and socially independent older people with/without diseases (hypertension, diabetes mellitus, cardiovascular diseases) in a Japanese age-specific cohort.

METHODS

We carried out a prospective cohort study including 1954 (1006 men and 948 women) Japanese individuals aged 64/65 years. Information on daily sleep duration, medical status, demographics, and lifestyle characteristics was collected by a baseline questionnaire survey and health checkup (2000-2005). Dates of incident dementia were confirmed using the nationally standardized dementia scale proposed by the Ministry of Health, Labor, and Welfare. A competing risk model was used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for incident dementia. We treated censored cases due to death as competing events.

RESULTS

During a median of 15.6 years of follow-up, 260 participants reported incident dementia. Compared with participants without diseases and who slept 6-7.9 h/day, those with a shorter daily sleep duration of <6 h/day, presence of disease and shorter, moderate, or longer daily sleep duration ≥8 h/day had an increased risk of incident dementia (HR 1.73; 95% CI 1.04-2.88, HR 1.98; 95% CI 1.14-3.44, HR 1.44; 95% CI 1.03-2.00, and HR 2.09; 95% CI 1.41-3.09, respectively) with a significant interaction between the presence of diseases and sleep duration (p < 0.001).

CONCLUSIONS

The present findings suggest that habitual sleep duration predicts future risk of dementia.

Exerkines and long-term synaptic potentiation: Mechanisms of exercise-induced neuroplasticity

Physical exercise may improve cognitive function by modulating molecular and cellular mechanisms within the brain. We propose that the facilitation of long-term synaptic potentiation (LTP)-related pathways, by products induced by physical exercise (i.e., exerkines), is a crucial aspect of the exercise-effect on the brain. This review summarizes synaptic pathways that are activated by exerkines and may potentiate LTP. For a total of 16 exerkines, we indicated how blood and brain exerkine levels are altered depending on the type of physical exercise (i.e., cardiovascular or resistance exercise) and how they respond to a single bout (i.e., acute exercise) or multiple bouts of physical exercise (i.e., chronic exercise). This information may be used for designing individualized physical exercise programs. Finally, this review may serve to direct future research towards fundamental gaps in our current knowledge regarding the biophysical interactions between muscle activity and the brain at both cellular and system levels.

Vascular Health Is Associated With Functional Connectivity Decline in Higher-Order Networks of Older Adults

Background

Poor vascular health may impede brain functioning in older adults, thus possibly increasing the risk of cognitive decline and Alzheimer’s disease (AD). The emerging link between vascular risk factors (VRF) and longitudinal decline in resting-state functional connectivity (RSFC) within functional brain networks needs replication and further research in independent cohorts.

Method

We examined 95 non-demented older adults using the IMAP+ cohort (Caen, France). VRF were assessed at baseline through systolic and diastolic blood pressure, body-mass-index, and glycated hemoglobin (HbA1c) levels. Brain pathological burden was measured using white matter hyperintensity (WMH) volumes, derived from FLAIR images, and cortical β-Amyloid (Aβ) deposition, derived from florbetapir-PET imaging. RSFC was estimated from functional MRI scans within canonical brain networks at baseline and up to 3 years of follow-up. Linear mixed-effects models evaluated the independent predictive value of VRF on longitudinal changes in network-specific and global RSFC as well as a potential association between these RSFC changes and cognitive decline.

Results

We replicate that RSFC increased over time in global RSFC and in the default-mode, salience/ventral-attention and fronto-parietal networks. In contrast, higher diastolic blood pressure levels were independently associated with a decrease of RSFC over time in the default-mode, salience/ventral-attention, and fronto-parietal networks. Moreover, higher HbA1c levels were independently associated with a reduction of the observed RSFC increase over time in the salience/ventral-attention network. Both of these associations were independent of brain pathology related to Aβ load and WMH volumes. The VRF-related changes in RSFC over time were not significantly associated with longitudinal changes in cognitive performance.

Conclusion

Our longitudinal findings corroborate that VRF promote RSFC alterations over time within higher-order brain networks, irrespective of pathological brain burden. Altered RSFC in large-scale cognitive networks may eventually increase the vulnerability to aging and AD.

Atrial Fibrillation Is Associated with Cognitive Impairment, All-Cause Dementia, Vascular Dementia, and Alzheimer's Disease: a Systematic Review and Meta-Analysis

BACKGROUND

Atrial fibrillation (AF) is a risk factor for cognitive impairment and dementia in patients with stroke history. However, the association between AF and cognitive impairment in broader populations is less clear.

OBJECTIVE

To systematically review and quantitatively synthesize the existing evidence regarding the association of AF with cognitive impairment of any severity and etiology and dementia.

METHODS

Medline, Scopus, and Cochrane Central were searched in order to identify studies investigating the association between AF and cognitive impairment (or dementia) cross-sectionally and longitudinally. Studies encompassing and analyzing exclusively patients with stroke history were excluded. A random-effects model meta-analysis was conducted. Potential sources of between-study heterogeneity were investigated via subgroup and meta-regression analyses. Sensitivity analyses including only studies reporting data on stroke-free patients, vascular dementia, and Alzheimer's disease were performed.

RESULTS

In total, 43 studies were included. In the pooled analysis, AF was significantly associated with dementia (adjusted OR, 1.6; 95% CI, 1.3 to 2.1; I², 31%) and the combined endpoint of cognitive impairment or dementia (pooled adjusted OR, 1.5; 95% CI, 1.4 to 1.8; I², 34%). The results were significant, even when studies including only stroke-free patients were pooled together (unadjusted OR, 2.2; 95% CI, 1.4 to 3.5; I², 96%), but the heterogeneity rates were high. AF was significantly associated with increased risk of both vascular (adjusted OR, 1.7; 95% CI, 1.2 to 2.3; I², 43%) and Alzheimer's dementia (adjusted HR, 1.4; 95% CI, 1.2 to 1.6; I², 42%).

CONCLUSION

AF increases the risk of cognitive impairment, all-cause dementia, vascular dementia, and Alzheimer's disease. Future studies should employ interventions that may delay or even prevent cognitive decline in AF patients.

Can Physical Activity Reduce the Risk of Cognitive Decline in Apolipoprotein e4 Carriers? A Systematic Review

Physical activity (PA) reduces the risk of cognitive decline (CD) in the general population. However, little is known about whether the presence of the apolipoprotein E epsilon 4 allele (APOE e4) could modify this beneficial effect. The aim of this systematic review was to analyze and synthetize the scientific evidence related to PA levels and CD risk in cognitively healthy APOE e4 carriers. Four electronic databases were analyzed. Only original articles with longitudinal study design were selected to analyze the relationship between PA and CD in APOE e4 carriers. Five studies were included in the systematic review. All studies except one stated that PA is a protective factor against CD in APOE e4 carriers. Moreover, partial support was found for the hypothesis that a greater amount and intensity of PA are more beneficial in CD prevention. The results support the idea that PA is a protective factor against CD in APOE e4 carriers. Nevertheless, it would be necessary to carry out further studies that would allow these findings to be contrasted.

Cardiovascular Risk and Cognitive Function in Middle-Aged and Older Hispanics/Latinos: Results from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

BACKGROUND

Cardiovascular disease is linked to cognitive decline and disorders (e.g., dementia). The evidence is based largely on older non-Latino White cohorts.

OBJECTIVE

Examine the association between global vascular risk and cognitive function among Hispanics/Latinos in the United States.

METHODS

We used data from a large sample of stroke- and cardiovascular disease-free, middle-aged and older Hispanics/Latinos with diverse backgrounds (n=7,650) from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). We compared associations between two measures of cardiovascular risk (CVR), the Framingham Cardiovascular Risk Score (FCRS) and the multiethnic Global Vascular Risk Score (GVRS), and cognitive performance using measures of global and domain specific cognitive function, and tested for modification by sex and age.

RESULTS

Higher FCRS and GVRS were associated with lower global cognition and higher probability of low mental status, after covariates adjustment. Both CVR indices were associated with lower performances in learning and memory, verbal fluency, and psychomotor speed. Higher GVRS presented stronger associations with lower cognitive function compared to the FCRS. Women and younger age (45-64 years) exhibited more pronounced associations between higher CVR and worse cognition, particularly so with the GVRS.

DISCUSSION

CVR is also a risk for compromised cognitive function and evident in middle-age among Hispanics/Latinos. The multiethnic GVRS, tailored to specific risks based on racial/ethnic background, is feasible to use in primary care settings and can provide important insight on cognitive risk. Even modest shifts in population toward cardiovascular health in the high-risk Hispanic/Latino population can have important positive impacts on healthy cognitive aging.

HIV, Vascular Risk Factors, and Cognition in the Combination Antiretroviral Therapy Era: A Systematic Review and Meta-Analysis

OBJECTIVES

Mounting evidence indicates that vascular risk factors (VRFs) are elevated in HIV and play a significant role in the development and persistence of HIV-associated neurocognitive disorder. Given the increased longevity of people living with HIV (PLWH), there is a great need to better elucidate vascular contributions to neurocognitive impairment in HIV. This systematic review and meta-analysis examine relationships between traditional VRFs, cardiovascular disease (CVD), and cognition in PLWH in the combination antiretroviral therapy era.

METHODS

For the systematic review, 44 studies met inclusion criteria and included data from 14,376 PLWH and 6,043 HIV-seronegative controls. To better quantify the contribution of VRFs to cognitive impairment in HIV, a robust variance estimation meta-analysis (N = 11 studies) was performed and included data from 2139 PLWH.

RESULTS

In the systematic review, cross-sectional and longitudinal studies supported relationships between VRFs, cognitive dysfunction, and decline, particularly in the domains of attention/processing speed, executive functioning, and fine motor skills. The meta-analysis demonstrated VRFs were associated with increased odds of global neurocognitive impairment (odds ratio [OR ]= 2.059, p = .010), which remained significant after adjustment for clinical HIV variables (p = .017). Analyses of individual VRFs demonstrated type 2 diabetes (p = .004), hyperlipidemia (p = .043), current smoking (p = .037), and previous CVD (p = .0005) were significantly associated with global neurocognitive impairment.

CONCLUSIONS

VRFs and CVD are associated with worse cognitive performance and decline, and neurocognitive impairment in PLWH. Future studies are needed to examine these relationships in older adults with HIV, and investigate how race/ethnicity, gender, medical comorbidities, and psychosocial factors contribute to VRF-associated cognitive dysfunction in HIV.

Sex Differences in Cardiovascular Disease and Cognitive Dysfunction in Rural West Elderly Texans

BACKGROUND

The prevalence of cognitive dysfunction increases in elderly due to cardiovascular disease related risk factors in rural communities like West Texas.

OBJECTIVE

The purpose of this study was to find risk factors of cardiovascular disease (CVD) related to cognitive dysfunction and their impact on elderly adults in rural West Texans.

METHODS

Statistical methods such as Pearson's chi-squared and a multinomial logistic regression were utilized to analyze data. We used SPSS software to detect and understand the nature of the risk factors.

RESULTS

A summary of statistics was obtained by using Pearson's chi-squared test for categorical variables. CVD, diabetes mellitus, and depression were significantly associated with cognitive dysfunction for both males and females (p = 0.0001), whereas anxiety was found to be significantly associated with cognitive dysfunction for females (p = 0.0001). Age group and race/ethnicity were significantly associated with cognitive dysfunction for both males and females (p = 0.0001). By performing a multinomial logistic regression method and controlling for confounders, the significant risk factors (p <  0.05)- age (65- 84 years), diabetes, and memory loss for age-associated cognitive impairment; diabetes for cognitive impairment no dementia; age (65- 84, ≥85 years), CVD, diabetes, depression, memory loss, non-Hispanic Whites, and Black/African-Americans for mild cognitive impairment; and age, memory loss, non-Hispanic Whites, Black/African-Americans, and male gender were found for dementia.

CONCLUSION

CVD related risk factors in developing cognitive dysfunction exist and integrating such risk variables may guide relevant policy interventions to reduce Alzheimer's incidence or dementia in rural communities in West Texans.

Association Between Elevated Depressive Symptoms and Cognitive Function Moderated by APOE4 Status: Framingham Offspring Study

BACKGROUND

Depression and Apolipoprotein E4 (APOE4) are associated with decreased cognitive function and differences in brain structure.

OBJECTIVE

This study investigated whether APOE4 status moderates the association between elevated depressive symptoms, cognitive function, and brain structure.

METHODS

Stroke- and dementia-free participants (n = 1,968) underwent neuropsychological evaluation, brain MRI, and depression screening. Linear and logistic regression was used to examine all associations. Secondary analyses were performed using interaction terms to assess effect modification by APOE4 status.

RESULTS

Elevated depressive symptoms were associated with lower cognitive performance in several domains. In stratified analyses, elevated depressive symptoms were associated with poorer visual short- and long-term memory performance for APOE4 + participants. Elevated depressive symptoms were not associated with any brain structure in this study sample.

CONCLUSION

Elevated depressive symptoms impact cognitive function in non-demented individuals. Having the APOE4 allele may exacerbate the deleterious effects of elevated depressive symptoms on visual memory performance. Screening for elevated depressive symptoms in both research studies and clinical practice may be warranted to avoid false positive identification of neurodegeneration, particularly among those who are APOE4 + .

Medial temporal lobe volumes in late-life depression: effects of age and vascular risk factors

Substantial work associates late-life depression with hippocampal pathology. However, there is less information about differences in hippocampal subfields and other connected temporal lobe regions and how these regions may be influenced by vascular factors. Individuals aged 60 years or older with and without a DSM-IV diagnosis of Major Depressive Disorder completed clinical assessments and 3 T cranial MRI using a protocol allowing for automated measurement of medial temporal lobe subfield volumes. A subset also completed pseudo-continuous arterial spin labeling, allowing for the measurement of hippocampal cerebral blood flow. In 59 depressed and 21 never-depressed elders (mean age = 66.4 years, SD = 5.8y, range 60-86y), the depressed group did not exhibit statistically significant volumetric differences for the total hippocampus or hippocampal subfields but did exhibit significantly smaller volumes of the perirhinal cortex, specifically in the BA36 region. Additionally, age had a greater effect in the depressed group on volumes of the cornu ammonis, entorhinal cortex, and BA36 region. Finally, both clinical and radiological markers of vascular risk were associated with smaller BA36 volumes, while reduced hippocampal blood flow was associated with smaller hippocampal and cornu ammonis volumes. In conclusion, while we did not observe group differences in hippocampal regions, we observed group differences and an effect of vascular pathology on the BA36 region, part of the perirhinal cortex. This is a critical region exhibiting atrophy in prodromal Alzheimer's disease. Moreover, the observed greater effect of age in the depressed groups is concordant with past longitudinal studies reporting greater hippocampal atrophy in late-life depression.

Investigating Predictors of Cognitive Decline Using Machine Learning

OBJECTIVES

Genetic risks for cognitive decline are not modifiable; however their relative importance compared to modifiable factors is unclear. We used machine learning to evaluate modifiable and genetic risk factors for Alzheimer's disease (AD), to predict cognitive decline.

METHODS

Health and Retirement Study participants, aged 65-90 years, with DNA and >2 cognitive evaluations, were included (n = 7,142). Predictors included age, body mass index, gender, education, APOE ε4, cardiovascular, hypertension, diabetes, stroke, neighborhood socioeconomic status (NSES), and AD risk genes. Latent class trajectory analyses of cognitive scores determined the form and number of classes. Random Forests (RF) classification investigated predictors of cognitive trajectories. Performance metrics (accuracy, sensitivity, and specificity) were reported.

RESULTS

Three classes were identified. Discriminating highest from lowest classes produced the best RF performance: accuracy = 78% (1.0%), sensitivity = 75% (1.0%), and specificity = 81% (1.0%). Top ranked predictors were education, age, gender, stroke, NSES, and diabetes, APOE ε4 carrier status, and body mass index (BMI). When discriminating high from medium classes, top predictors were education, age, gender, stroke, diabetes, NSES, and BMI. When discriminating medium from the low classes, education, NSES, age, diabetes, and stroke were top predictors.

DISCUSSION

The combination of latent trajectories and RF classification techniques suggested that nongenetic factors contribute more to cognitive decline than genetic factors. Education was the most relevant predictor for discrimination.

Adverse Vascular Risk Relates to Cerebrospinal Fluid Biomarker Evidence of Axonal Injury in the Presence of Alzheimer's Disease Pathology

BACKGROUND

Vascular risk factors promote cerebral small vessel disease and neuropathological changes, particularly in white matter where large-caliber axons are located. How Alzheimer's disease pathology influences the brain's vulnerability in this regard is not well understood.

OBJECTIVE

Systemic vascular risk was assessed in relation to cerebrospinal fluid concentrations of neurofilament light, a biomarker of large-caliber axonal injury, evaluating for interactions by clinical and protein markers of Alzheimer's disease.

METHODS

Among Alzheimer's Disease Neuroimaging Initiative participants with normal cognition (n = 117), mild cognitive impairment (n = 190), and Alzheimer's disease (n = 95), linear regression related vascular risk (as measured by the modified Framingham Stroke Risk Profile) to neurofilament light, adjusting for age, sex, education, and cognitive diagnosis. Interactions were assessed by cognitive diagnosis, and by cerebrospinal fluid markers of Aβ42, hyperphosphorylated tau, and total tau.

RESULTS

Vascular risk and neurofilament light were not related in the main effect model (p = 0.08). However, interactions emerged for total tau (p = 0.01) and hyperphosphorylated tau (p = 0.002) reflecting vascular risk becoming more associated with cerebrospinal fluid neurofilament light in the context of greater concentrations of tau biomarkers. An interaction also emerged for the Alzheimer's disease biomarker profiles (p = 0.046) where in comparison to the referent 'normal' biomarker group, individuals with abnormal levels of both Aβ42 and total tau showed stronger associations between vascular risk and neurofilament light.

CONCLUSION

Older adults may be more vulnerable to axonal injury in response to higher vascular risk burdens in the context of concomitant Alzheimer's disease pathology.

Exercise benefits on Alzheimer's disease: State-of-the-science

Although there is no unanimity, growing evidence supports the value of regular physical exercise to prevent Alzheimer's disease as well as cognitive decline in affected patients. Together with an introductory summary on epidemiological evidence, the aim of this review is to summarize the current knowledge on the potential biological mechanisms underlying exercise benefits in this condition. Regular physical exercise has proven to be beneficial for traditional cardiovascular risk factors (e.g., reduced vascular flow, diabetes) involved in the pathogenesis of Alzheimer's disease. Exercise also promotes neurogenesis via increases in exercise-induced metabolic factors (e.g., ketone bodies, lactate) and muscle-derived myokines (cathepsin-B, irisin), which in turn stimulate the production of neurotrophins such as brain-derived neurotrophic factor. Finally, regular exercise exerts anti-inflammatory effects and improves the brain redox status, thereby ameliorating the pathophysiological hallmarks of Alzheimer's disease (e.g., amyloid-β deposition). In summary, physical exercise might provide numerous benefits through different pathways that might, in turn, help prevent risk and progression of Alzheimer's disease. More evidence is needed, however, based on human studies.

Treatable Vascular Risk and Cognitive Performance in Persons Aged 35 Years or Older: Longitudinal Study of Six Years

Background

Poor cognitive performance is associated with high vascular risk. However, this association is only investigated in elderly. As neuropathological changes precede clinical symptoms of cognitive impairment by several decades, it is likely that cognitive performance is already associated with vascular risk at middle-age.

Objectives

To investigate the association of cognitive performance with treatable vascular risk in middle-aged and old persons.

Design

Longitudinal study with three measurements during follow-up period of 5.5 years.

Setting

City of Groningen, the Netherlands.

Participants

Cohort of 3,572 participants (age range, 35–82 years; mean age, 54 years; men, 52%).

Exposure

Treatable vascular risk as defined by treatable components of the Framingham Risk Score for Cardiovascular Disease at the first measurement (diabetes mellitus, smoking, hypercholesterolemia and hypertension).

Measurements

Change in cognitive performance during follow-up. Cognitive performance was measured with Ruff Figural Fluency Test (RFFT) and Visual Association Test (VAT), and calculated as the average of the standardized RFFT and VAT score per participant.

Results

The mean (SD) cognitive performance changed from 0.00 (0.79) at the first measurement to 0.15 (0.83) at second measurement and to 0.39 (0.82) at the third measurement (Ptrend<0.001). This change was negatively associated with treatable vascular risk: the change in cognitive performance between two measurements decreased with 0.004 per one-point increment of treatable vascular risk (95%CI, -0.008 to 0.000; P=0.05) and with 0.006 per one-year increment of age (95%CI, -0.008 to -0.004; P<0.001).

Conclusions

Change in cognitive performance was associated with treatable vascular risk in persons aged 35 years or older.

Electronic Supplementary Material

Supplementary material is available for this article at 10.14283/jpad.2018.47 and is accessible for authorized users.

Neuroinflammation in pathogenesis of Alzheimer's disease: Phytochemicals as potential therapeutics

Accumulation of neurotoxic forms of amyloid-β proteins in senile plaques and hyperphosphorylated tau proteins in neurofibrillary tangles is a well-known pathophysiological hallmark of Alzheimer's disease (AD). However, clinical trials with drugs targeting amyloid-β and tau have failed to demonstrate efficacy in treating AD. All currently FDA-approved anti-AD drugs have symptomatic effects only and are not able to cure this disease. This makes necessary to search for alternative therapeutic targets. Accumulating evidence suggests that systemic inflammation and related vascular dysfunction play important etiological roles in AD and precede its clinical manifestation. Therefore, novel therapeutic modalities targeted at these pathophysiological components of AD are intensively developed now. Phytochemicals such as resveratrol, curcumin, quercetin, genistein and catechins are promising anti-AD therapeutics due to their ability to affect major pathogenetic mechanisms of AD, including oxidative stress, neuroinflammation and mitochondrial dysfunction. The implementation of innovative approaches for phytochemical delivery, including the nanotechnology-based ones which enable to significantly enhance their oral bioavailability, would likely provide an opportunity to address many challenges of conventional anti-AD therapies. In this review, roles of inflammation and vascular dysregulation in AD are described and phytobioactive compound-based treatment strategies for AD are discussed.

Revised Framingham Stroke Risk Profile: Association with Cognitive Status and MRI-Derived Volumetric Measures

BACKGROUND

The Framingham Stroke Risk Profile (FSRP) was created in 1991 to estimate 10-year risk of stroke. It was revised in 2017 (rFSRP) to reflect the modern data on vascular risk factors and stroke risk.

OBJECTIVE

This study examined the association between the rFSRP and cognitive and brain aging outcomes among participants from the National Alzheimer's Coordinating Center (NACC) Uniform Data Set (UDS).

METHODS

Cross-sectional rFSRP was computed at baseline for 19,309 participants (mean age = 72.84, SD = 8.48) from the NACC-UDS [9,697 (50.2%) normal cognition, 4,705 (24.4%) MCI, 4,907 (25.4%) dementia]. Multivariable linear, logistic, or ordinal regressions examined the association between the rFSRP and diagnostic status, neuropsychological test performance, CDR® Sum of Boxes, as well as total brain volume (TBV), hippocampal volume (HCV), and log-transformed white matter hyperintensities (WMH) for an MRI subset (n = 1,196). Models controlled for age, sex, education, racial identity, APOEɛ4 status, and estimated intracranial volume for MRI models.

RESULTS

The mean rFSRP probability was 10.42% (min = 0.50%, max = 95.71%). Higher rFSRP scores corresponded to greater CDR Sum of Boxes (β= 0.02, p = 0.028) and worse performance on: Trail Making Test A (β= 0.05, p < 0.001) and B (β= 0.057, p < 0.001), and Digit Symbol (β= -0.058, p < 0.001). Higher rFSRP scores were associated with increased odds for a greater volume of log-transformed WMH (OR = 1.02 per quartile, p = 0.015). No associations were observed for diagnosis, episodic memory or language test scores, HCV, or TBV.

CONCLUSION

These results support the rFSRP as a useful metric to facilitate clinical research on the associations between cerebrovascular disease and cognitive and brain aging.

Association Between Carotid Artery Intima-Media Thickness and Combinations of Mild Cognitive Impairment and Pre-Frailty in Older Adults

Carotid intima-media thickness (CIMT) has been proposed as a surrogate marker of cardiovascular disease. Mild cognitive impairment (MCI) and pre-frailty are reportedly associated with increased CIMT. As the evidence on the association of CIMT with combinations of MCI and pre-frailty is limited, this association is examined. A total of 231 older adults participated. MCI was defined according to clinical consensus or psychometric criteria by a dementia specialist, and considering detailed neuropsychological assessments. Also, pre-frailty was defined as subjects with frail component of 1 or 2. Carotid variables were measured using a B-mode ultrasound. The analysis of covariance (ANCOVA) was performed to assess independent differences in CIMT among the four groups, according to the cognitive function and frailty status after a multivariate adjustment. Increased CIMT is associated with combinations of MCI and pre-frailty. ANCOVA showed that CIMTs were significantly different among the four groups according to the cognitive function and frailty status. CIMTmax combined with MCI and pre-frailty was the thickest (1.04 ± 0.3 mm), whereas the CIMT of no MCI and no pre-frailty was the thinnest (0.82 ± 0.2 mm). The results suggest that combinations of MCI and pre-frailty are associated with increased CIMT in older adults.

Combining modifiable risk factors and risk of dementia: a systematic review and meta-analysis

OBJECTIVE

To systematically review the literature relating to the impact of multiple co-occurring modifiable risk factors for cognitive decline and dementia.

DESIGN

A systematic review and meta-analysis of the literature relating to the impact of co-occurring key risk factors for incident cognitive decline and dementia. All abstracts and full text were screened independently by two reviewers and each article assessed for bias using a standard checklist. A fixed effects meta-analysis was undertaken.

DATA SOURCES

Databases Medline, Embase and PsycINFO were searched from 1999 to 2017.

ELIGIBILITY CRITERIA

For inclusion articles were required to report longitudinal data from participants free of cognitive decline at baseline, with formal assessment of cognitive function or dementia during follow-up, and an aim to examine the impact of additive or clustered comorbid risk factor burden in with two or more core modifiable risk factors.

RESULTS

Seventy-nine full-text articles were examined. Twenty-two articles (18 studies) were included reporting data on >40 000 participants. Included studies consistently reported an increased risk associated with greater numbers of intraindividual risk factors or unhealthy behaviours and the opposite for healthy or protective behaviours. A meta-analysis of studies with dementia outcomes resulted in a pooled relative risk for dementia of 1.20 (95% CI 1.04 to 1.39) for one risk factor, 1.65 (95% CI 1.40 to 1.94) for two and 2.21 (95% CI 1.78 to 2.73) for three or more, relative to no risk factors. Limitations include dependence on published results and variations in study outcome, cognitive assessment, length of follow-up and definition of risk factor exposure.

CONCLUSIONS

The strength of the reported associations, the consistency across studies and the suggestion of a dose response supports a need to keep modifiable risk factor exposure to a minimum and to avoid exposure to additional modifiable risks. Further research is needed to establish whether particular combinations of risk factors confer greater risk than others.

PROSPERO REGISTRATION NUMBER

42016052914.

Cognition and drug adherence to oral hypoglycemic and antihypertensive agents in older adults

Background and objectives: Chronic disorders such as diabetes mellitus type II and hypertension have been associated with cognitive decline in older adults. It is unclear whether adherence to antihypertensive and oral hypoglycemic agents impact cognitive health. The objectives are to study the association between adherence to antihypertensive and oral hypoglycemic agents and cognitive status in community-living older adults. Methods: We used data from a large representative sample of older adults (N=2,286) covered under a public drug insurance plan in Quebec and participating in Quebec's health survey on older adults (ESA-study) with a Mini-Mental State Examination (MMSE) score ≥22 at baseline (T1) and examined one year later (T2). Participants with hypertension and diabetes mellitus type II were identified according to criteria used in the Canadian Chronic Disease Surveillance System. Antihypertensive and oral hypoglycemic prescriptions delivered were ascertained via Quebec's pharmaceutical database (RAMQ). Medication adherence was calculated using the medication possession ratio as a continuous variable in the year prior to and following baseline interview. Multivariate linear regressions were used to study the percentage change in MMSE scores between interviews (T1,T2) as a function of adherence to antihypertensive and oral hypoglycemic agents (before and after T1) controlling for potential confounders. Results: In participants with diabetes mellitus type II only, adherence to oral hypoglycemics was not associated with a change in MMSE scores. In participants with hypertension only, the change in MMSE scores was associated with adherence to antihypertensives (β 1.23; 95%CI: 0.29-2.17). In participants with comorbid hypertension and diabetes mellitus type II, the change in MMSE scores was associated with adherence to both antihypertensive and oral hypoglycemic agents (β 0.75; 95%CI: 0.01-1.48). Conclusions: Adherence to oral hypoglycemic agents and antihypertensive agents among older adults with hypertension and comorbid diabetes mellitus type II can have a preserving effect on cognitive health in older adults. Further research on the long-term impact on cognition is recommended.

Framingham Risk Score and the Risk of Progression from Mild Cognitive Impairment to Dementia

BACKGROUND

Mild cognitive impairment (MCI) often represents the clinical manifestation of cognitive deterioration preceding Alzheimer's disease (AD). Currently, there are no reliable approaches for an objective evaluation of the risk of developing AD in MCI patients.

OBJECTIVE

The aim of this study was to verify whether the Framingham cardiovascular risk profile (FCRP) could be useful to identify patients at the highest risk of conversion from MCI to AD.

METHODS

Patients with amnestic MCI (aMCI) were carefully investigated to assess their vascular risk profile. They were also submitted to a comprehensive neuropsychological evaluation. The FCRP was calculated for each patient and the apolipoprotein E (ApoE) genotype was determined from peripheral blood cells. The main outcome was defined as a conversion to AD within 24 months after inclusion.

RESULTS

385 consecutive aMCI subjects were included. Age, FCRP, and vascular age showed a fairly predictive value on conversion to AD. Selecting the subpopulation of ApoE ɛ4 carriers, we observed that FCRP had an increased performance in predicting the conversion. The rate of conversion increased from 12.5% in the FCRP low-risk group to 43.2% in the high-risk group (p < 0.0001). ApoE ɛ4 carriers had a 3.7-times increased probability of conversion with respect to the other subjects (p < 0.0001).

CONCLUSIONS

FCRP assessment could be considered a reliable approach to predict conversion to AD in aMCI subjects. The presence of ApoE ɛ4 increases significantly the risk of conversion. These data confirm the narrow relationship between genetic and vascular risk factors in influencing the evolution of cognitive impairment.

Does cognitive impairment impact adherence? A systematic review and meta-analysis of the association between cognitive impairment and medication non-adherence in stroke

BACKGROUND

While medication adherence is essential for the secondary prevention of stroke, it is often sub-optimal, and can be compromised by cognitive impairment. This study aimed to systematically review and meta-analyse the association between cognitive impairment and medication non-adherence in stroke.

METHODS

A systematic literature search of longitudinal and cross-sectional studies of adults with any stroke type, which reported on the association between any measure of non-adherence and cognitive impairment, was carried out according to PRISMA guidelines. Odds ratios and 95% confidence intervals were the primary measure of effect. Risk of bias was assessed using the Cochrane Bias Methods Group's Tool to Assess Risk of Bias in Cohort Studies, with evidence quality assessed according to the GRADE approach. We conducted sensitivity analyses according to measure of cognitive impairment, measure of medication adherence, population, risk of bias and adjustment for covariates. The protocol was registered with PROSPERO.

RESULTS

From 1,760 titles and abstracts, we identified 9 studies for inclusion. Measures of cognitive impairment varied from dementia diagnosis to standardised cognitive assessments. Medication adherence was assessed through self-report or administrative databases. The majority of studies were of medium risk of bias (n = 6); two studies had low risk of bias. Findings were mixed; when all studies were pooled, there was no evidence of an association between cognitive impairment and medication non-adherence post-stroke [OR (95% CI): 0.85 (0.66, 1.03)]. However, heterogeneity was substantial [I2 = 90.9%, p < .001], and the overall evidence quality was low.

CONCLUSIONS

Few studies have explored associations between cognitive impairment and medication adherence post-stroke, with substantial heterogeneity in study populations, and definitions and assessments of non-adherence and cognitive impairment. Further research using clear, standardised and objective assessments is needed to clarify the association between cognitive impairment and medication non-adherence in stroke.

Divergent Roles of Vascular Burden and Neurodegeneration in the Cognitive Decline of Geriatric Depression Patients and Mild Cognitive Impairment Patients

Both geriatric depression and mild cognitive impairment (MCI) confer an increased risk for the development of dementia. The mechanisms underlying the development of cognitive impairment in geriatric depression patients remain controversial. The present study aimed to explore the association of cognitive decline with vascular risk, white matter hyperintensity (WMH) burden and hippocampal volume in both remitted geriatric depression (RGD) subjects and amnestic mild cognitive impairment (aMCI) subjects. Forty-one RGD subjects, 51 aMCI subjects, and 64 healthy elderly subjects underwent multimodal MRI scans and neuropsychological tests at both baseline and a 35-month follow-up. According to the changing patterns (declining or stable) of global cognitive function during the follow-up period, each group was further divided into a declining subgroup and a stable subgroup. The Framingham 10-year cardiovascular risk, WMH volume and hippocampal volume were measured to assess vascular pathology and neurodegeneration, respectively. The RGD declining group displayed a higher vascular risk and greater WMH volume than the RGD stable group, whereas no such difference was found in the aMCI subjects. In contrast, the aMCI declining group displayed a smaller left hippocampal volume than the aMCI stable group, whereas no such difference was found in the RGD subjects. Furthermore, greater increases in the WHM volume correlated with greater decreases in global cognitive function in the RGD declining group, and greater decreases in the left hippocampal volume correlated with greater decreases in global cognitive function in the aMCI declining group. In conclusion, the cognitive decline in RGD patients is associated with vascular burden, whereas the cognitive decline in aMCI patients is associated with neurodegeneration. These findings could contribute to a better understanding of the specific mechanisms of the development of dementia in each condition.

Modeling the Relationships Among Late-Life Body Mass Index, Cerebrovascular Disease, and Alzheimer's Disease Neuropathology in an Autopsy Sample of 1,421 Subjects from the National Alzheimer's Coordinating Center Data Set

The relationship between late-life body mass index (BMI) and Alzheimer's disease (AD) is poorly understood due to the lack of research in samples with autopsy-confirmed AD neuropathology (ADNP). The role of cerebrovascular disease (CVD) in the interplay between late-life BMI and ADNP is unclear. We conducted a retrospective longitudinal investigation and used joint modeling of linear mixed effects to investigate causal relationships among repeated antemortem BMI measurements, CVD (quantified neuropathologically), and ADNP in an autopsy sample of subjects across the AD clinical continuum. The sample included 1,421 subjects from the National Alzheimer's Coordinating Center's Uniform Data Set and Neuropathology Data Set with diagnoses of normal cognition (NC; n = 234), mild cognitive impairment (MCI; n = 201), or AD dementia (n = 986). ADNP was defined as moderate to frequent neuritic plaques and Braak stageIII-VI. Ischemic Injury Scale (IIS) operationalized CVD. Joint modeling examined relationships among BMI, IIS, and ADNP in the overall sample and stratified by initial visit Clinical Dementia Rating score. Subject-specific random intercept for BMI was the predictor for ADNP due to minimal BMI change (p = 0.3028). Analyses controlling for demographic variables and APOE ɛ4 showed lower late-life BMI predicted increased odds of ADNP in the overall sample (p < 0.001), and in subjects with CDR of 0 (p = 0.0021) and 0.5 (p = 0.0012), but not ≥1.0 (p = 0.2012). Although higher IIS predicted greater odds of ADNP (p < 0.0001), BMI did not predict IIS (p = 0.2814). The current findings confirm lower late-life BMI confers increased odds for ADNP. Lower late-life BMI may be a preclinical indicator of underlying ADNP.

The frequency and influence of dementia risk factors in prodromal Alzheimer's disease

We investigated whether dementia risk factors were associated with prodromal Alzheimer's disease (AD) according to the International Working Group-2 and National Institute of Aging-Alzheimer's Association criteria, and with cognitive decline. A total of 1394 subjects with mild cognitive impairment from 14 different studies were classified according to these research criteria, based on cognitive performance and biomarkers. We compared the frequency of 10 risk factors between the subgroups, and used Cox-regression to examine the effect of risk factors on cognitive decline. Depression, obesity, and hypercholesterolemia occurred more often in individuals with low-AD-likelihood, compared with those with a high-AD-likelihood. Only alcohol use increased the risk of cognitive decline, regardless of AD pathology. These results suggest that traditional risk factors for AD are not associated with prodromal AD or with progression to dementia, among subjects with mild cognitive impairment. Future studies should validate these findings and determine whether risk factors might be of influence at an earlier stage (i.e., preclinical) of AD.

Genetic resilience to amyloid related cognitive decline

Preclinical Alzheimer's disease (AD) is characterized by amyloid deposition in the absence of overt clinical impairment. There is substantial heterogeneity in the long-term clinical outcomes among amyloid positive individuals, yet limited work has focused on identifying molecular factors driving resilience from amyloid-related cognitive impairment. We apply a recently developed predicted gene expression analysis (PrediXcan) to identify genes that modify the association between baseline amyloid deposition and longitudinal cognitive changes. Participants free of clinical AD (n = 631) were selected from the AD Neuroimaging Initiative (ADNI) who had a baseline positron emission tomography measure of amyloid deposition (quantified as a standard uptake value ratio), longitudinal neuropsychological data, and genetic data. PrediXcan was used to impute gene expression levels across 15 heart and brain tissues. Mixed effect regression models assessed the interaction between predicted gene expression levels and amyloid deposition on longitudinal cognitive outcomes. The predicted gene expression levels for two genes in the coronary artery (CNTLN, PROK1) and two genes in the atrial appendage (PRSS50, PROK1) interacted with amyloid deposition on episodic memory performance. The predicted gene expression levels for two additional genes (TMC4 in the basal ganglia and HMBS in the aorta) interacted with amyloid deposition on executive function performance. Post-hoc analyses provide additional validation of the HMBS and PROK1 effects across two independent subsets of ADNI using two additional metrics of amyloid deposition. These results highlight a subset of unique candidate genes of resilience and provide evidence that cell-cycle regulation, angiogenesis, and heme biosynthesis likely play a role in AD progression.

Youthful Processing Speed in Older Adults: Genetic, Biological, and Behavioral Predictors of Cognitive Processing Speed Trajectories in Aging

Objective: To examine the impact of genetic, inflammatory, cardiovascular, lifestyle, and neuroanatomical factors on cognitive processing speed (CPS) change over time in functionally intact older adults.

Methods: This observational study conducted over two time points, included 120 community dwelling cognitively normal older adults between the ages of 60 and 80 from the University of California San Francisco Memory and Aging Center. Participants were followed with composite measures of CPS, calculated based on norms for 20–30 year-olds. Variables of interest were AD risk genes (APOE, CR1), markers of inflammation (interleukin 6) and cardiovascular health (BMI, LDL, HDL, mean arterial pressure, fasting insulin), self-reported physical activity, and corpus callosum (CC) volumes. The sample was divided into three groups: 17 “resilient-agers” with fast and stable processing speed; 56 “average-agers” with average and stable processing speed; and 47 “sub-agers” with average baseline speed who were slower at follow-up.

Results: Resilient-agers had larger baseline CC volumes than sub-agers (p < 0.05). Resilient-agers displayed lower levels of interleukin-6 (IL-6) and insulin (ps < 0.05) than sub-agers, and reported more physical activity than both average- and sub-agers (ps < 0.01). In a multinomial logistic regression, physical activity and IL-6 predicted average- and sub-ager groups. Resilient-agers displayed a higher frequency of APOE e4 and CR1 AA/AG alleles.

Conclusion: Robust and stable CPS is associated with larger baseline CC volumes, lower levels of inflammation and insulin, and greater self-reported physical activity. These findings highlight the relevance of neuroanatomical, biological, and lifestyle factors in the identification and prediction of heterogeneous cognitive aging change over time.

Life and death in the trash heap: The ubiquitin proteasome pathway and UCHL1 in brain aging, neurodegenerative disease and cerebral Ischemia

The ubiquitin proteasome pathway (UPP) is essential for removing abnormal proteins and preventing accumulation of potentially toxic proteins within the neuron. UPP dysfunction occurs with normal aging and is associated with abnormal accumulation of protein aggregates within neurons in neurodegenerative diseases. Ischemia disrupts UPP function and thus may contribute to UPP dysfunction seen in the aging brain and in neurodegenerative diseases. Ubiquitin carboxy-terminal hydrolase L1 (UCHL1), an important component of the UPP in the neuron, is covalently modified and its activity inhibited by reactive lipids produced after ischemia. As a result, degradation of toxic proteins is impaired which may exacerbate neuronal function and cell death in stroke and neurodegenerative diseases. Preserving or restoring UCHL1 activity may be an effective therapeutic strategy in stroke and neurodegenerative diseases.

Pathophysiologic relationship between Alzheimer's disease, cerebrovascular disease, and cardiovascular risk: A review and synthesis

As the population ages due to demographic trends and gains in life expectancy, the incidence and prevalence of dementia increases, and the need to understand the etiology and pathogenesis of dementia becomes ever more urgent. Alzheimer's disease (AD), the most common form of dementia, is a complex disease, the mechanisms of which are poorly understood. The more we learn about AD, the more questions are raised about our current conceptual models of disease. In the absence of a cure or the means by which to slow disease progress, it may be prudent to apply our current knowledge of the intersection between AD, cardiovascular disease, and cerebrovascular disease to foster efforts to delay or slow the onset of AD. This review discusses our current understanding of the epidemiology, genetics, and pathophysiology of AD, the intersection between AD and vascular causes of dementia, and proposes future directions for research and prevention.

Late-Life Body Mass Index, Rapid Weight Loss, Apolipoprotein E ε4 and the Risk of Cognitive Decline and Incident Dementia

OBJECTIVES

To examine the effect of late-life body mass index (BMI) and rapid weight loss on incident mild cognitive impairment (MCI) and Alzheimer's disease (AD).

DESIGN

Prospective longitudinal cohort study.

SETTING

National Alzheimer's Coordinating Center (NACC) Uniform Data Set, including 34 past and current National Institute on Aging-funded AD Centers across the United States.

PARTICIPANTS

6940 older adults (n=5061 normal cognition [NC]; n=1879 MCI).

MEASUREMENTS

BMI (kg/m2) and modified Framingham Stroke Risk Profile (FSRP) score (sex, age, systolic blood pressure, anti-hypertension medication, diabetes mellitus, cigarette smoking, prevalent cardiovascular disease, atrial fibrillation) were assessed at baseline. Cognition and weight were assessed annually.

RESULTS

Multivariable binary logistic regression, adjusting for age, sex, race, education, length of follow-up, and modified FSRP related late-life BMI to risk of diagnostic conversion from NC to MCI or AD and from MCI to AD. Secondary analyses related late-life BMI to diagnostic conversion in the presence of rapid weight loss (>5% decrease in 12 months) and apolipoprotein E (APOE) ε4. During a mean 3.8-year follow-up period, 12% of NC participants converted to MCI or AD and 49% of MCI participants converted to AD. Higher baseline BMI was associated with a reduced probability of diagnostic conversion, such that for each one-unit increase in baseline BMI there was a reduction in diagnostic conversion for both NC (OR=0.977, 95%CI 0.958-0.996, p=0.015) and MCI participants (OR=0.962, 95%CI 0.942-0.983, p<0.001). The protective effect of higher baseline BMI did not persist in the setting of rapid weight loss but did persist when adjusting for APOE ε4.

CONCLUSIONS

Higher late-life BMI is associated with a lower risk of incident MCI and AD but is not protective in the presence of rapid weight loss.

Resting-State Cardiac Workload is Related to Both Increased Neocortical Aggregation of Amyloid-β and Relative Impairments in Spatial Working Memory in Pre-Clinical Alzheimer's Disease

We sought to determine whether there is any association between a cardiac workload marker, rate pressure product (RPP), working memory, and cortical amyloid-β (Aβ) burden in 63 cognitively normal midlife adults (Mage = 62.8 years; range = 55 to 75 years) at risk for Alzheimer's disease (AD). The results show a small-to-moderate relationship between increasing cardiac workload (at rest) and neocortical amyloidosis in individuals at the preclinical stage of AD. Moreover, increasing RPP was linearly related to increasing relative impairments on a spatial working memory task (R2 = 0.30), but only for those individuals with neuroimaging evidence suggestive of preclinical AD. These results support a relationship between the aggregation of Aβ protein plaques in the neocortex, increased cognitive impairment, and more inefficient myocardial oxygen use in the absence of significant metabolic demands.

Healthy Ageing Through Internet Counselling in the Elderly: the HATICE randomised controlled trial for the prevention of cardiovascular disease and cognitive impairment

INTRODUCTION

Cardiovascular disease and dementia share a number of risk factors including hypertension, hypercholesterolaemia, smoking, obesity, diabetes and physical inactivity. The rise of eHealth has led to increasing opportunities for large-scale delivery of prevention programmes encouraging self-management. The aim of this study is to investigate whether a multidomain intervention to optimise self-management of cardiovascular risk factors in older individuals, delivered through an coach-supported interactive internet platform, can improve the cardiovascular risk profile and reduce the risk of cardiovascular disease and cognitive decline.

METHODS AND ANALYSIS

HATICE is a multinational, multicentre, prospective, randomised, open-label blinded end point (PROBE) trial with 18 months intervention. Recruitment of 2600 older people (≥65 years) at increased risk of cardiovascular disease will take place in the Netherlands, Finland and France. Participants randomised to the intervention condition will have access to an interactive internet platform, stimulating self-management of vascular risk factors, with remote support by a coach. Participants in the control group will have access to a static internet platform with basic health information.The primary outcome is a composite score based on the average z-score of the difference between baseline and 18 months follow-up values of systolic blood pressure, low-density-lipoprotein and body mass index. Main secondary outcomes include the effect on the individual components of the primary outcome, the effect on lifestyle-related risk factors, incident cardiovascular disease, mortality, cognitive functioning, mood and cost-effectiveness.

ETHICS AND DISSEMINATION

The study was approved by the medical ethics committee of the Academic Medical Center in Amsterdam, the Comité de Protection des Personnes Sud Ouest et Outre Mer in France and the Northern Savo Hospital District Research Ethics Committee in Finland.We expect that data from this study will result in a manuscript published in a peer-reviewed clinical open access journal.

TRIAL REGISTRATION NUMBER

ISRCTN48151589.

Diabetes and ageing-induced vascular inflammation

Diabetes and the ageing process independently increase the risk for cardiovascular disease (CVD). Since incidence of diabetes increases as people get older, the diabetic older adults represent the largest population of diabetic subjects. This group of patients would potentially be threatened by the development of CVD related to both ageing and diabetes. The relationship between CVD, ageing and diabetes is explained by the negative impact of these conditions on vascular function. Functional and clinical evidence supports the role of vascular inflammation induced by the ageing process and by diabetes in vascular impairment and CVD. Inflammatory mechanisms in both aged and diabetic vasculature include pro-inflammatory cytokines, vascular hyperactivation of nuclear factor-кB, increased expression of cyclooxygenase and inducible nitric oxide synthase, imbalanced expression of pro/anti-inflammatory microRNAs, and dysfunctional stress-response systems (sirtuins, Nrf2). In contrast, there are scarce data regarding the interaction of these mechanisms when ageing and diabetes co-exist and its impact on vascular function. Older diabetic animals and humans display higher vascular impairment and CVD risk than those either aged or diabetic, suggesting that chronic low-grade inflammation in ageing creates a vascular environment favouring the mechanisms of vascular damage driven by diabetes. Further research is needed to determine the specific inflammatory mechanisms responsible for exacerbated vascular impairment in older diabetic subjects in order to design effective therapeutic interventions to minimize the impact of vascular inflammation. This would help to prevent or delay CVD and the specific clinical manifestations (cognitive decline, frailty and disability) promoted by diabetes-induced vascular impairment in the elderly.

Mild cognitive decline. A position statement of the Cognitive Decline Group of the European Innovation Partnership for Active and Healthy Ageing (EIPAHA)

INTRODUCTION

Mild cognitive impairment (MCI) is a term used to describe a level of decline in cognition which is seen as an intermediate stage between normal ageing and dementia, and which many consider to be a prodromal stage of neurodegeneration that may become dementia. That is, it is perceived as a high risk level of cognitive change. The increasing burden of dementia in our society, but also our increasing understanding of its risk factors and potential interventions, require diligent management of MCI in order to find strategies that produce effective prevention of dementia.

AIM

To update knowledge regarding mild cognitive impairment, and to bring together and appraise evidence about the main features of clinical interest: definitions, prevalence and stability, risk factors, screening, and management and intervention.

METHODS

Literature review and consensus of expert opinion.

RESULTS AND CONCLUSION

MCI describes a level of impairment in which deteriorating cognitive functions still allow for reasonable independent living, including some compensatory strategies. While there is evidence for some early risk factors, there is still a need to more precisely delineate and distinguish early manifestations of frank dementia from cognitive impairment that is less likely to progress to dementia, and furthermore to develop improved prospective evidence for positive response to intervention. An important limitation derives from the scarcity of studies that take MCI as an endpoint. Strategies for effective management suffer from the same limitation, since most studies have focused on dementia. Behavioural changes may represent the most cost-effective approach.

Stroke risk interacts with Alzheimer's disease biomarkers on brain aging outcomes

Alzheimer's disease (AD) biomarkers and stroke risk factors independently predict cognitive impairment, likely through independent disease pathways. However, limited work has sought to describe the dynamic interplay between these important risk factors. This article evaluated the interaction between stroke risk and AD biomarkers on hippocampal volume and cognitive performance. We first evaluated the interaction between stroke risk factors and AD biomarkers using data from the Alzheimer's Disease Neuroimaging Initiative (ADNI, n = 1202). We then extended our findings to an independent autopsy data set from the National Alzheimer's Coordinating Center (NACC, n = 1122) using measures of AD pathology. Stroke risk was quantified using the Framingham Stroke Risk Profile. In ADNI, stroke risk interacted with tau and amyloid levels in relation to baseline and longitudinal cognitive performance. Similarly, in NACC, stroke risk interacted with amyloid and tau positivity on cognitive performance. The effect of stroke risk factors on cognition was strongest in the absence of AD biomarkers or neuropathology, providing additional evidence that AD biomarkers and stroke risk factors relate to cognition through independent pathways.