Effect of vascular burden as measured by vascular indexes upon vascular dementia: a matched case-control study

Polyvascular atherosclerosis and renal dysfunction increase the odds of cognitive impairment in vascular disease: findings of the LipidCardio study

INTRODUCTION

Growing evidence suggests a causal role for atherosclerotic vascular disease in cognitive impairment and dementia. Atherosclerosis may present as monovascular disease (monoVD) or as widespread polyvascular atherosclerotic disease (polyVD). Evidence on the relationship between monoVD or polyVD and cognitive impairment is limited.

METHODS

We conducted a cross-sectional analysis of baseline data from the LipidCardio Study. The main outcome measure was the presence of cognitive impairment, defined as a Mini-Mental State Examination (MMSE) score < 26.

RESULTS

The mean age was 71.5 years, 30.3% were female, 17.3% had no evidence of large-vessel atherosclerosis, 71.1% had monoVD, and 11.7% had polyVD, defined as the presence of atherosclerosis in ≥ 2 vascular territories (coronary, cerebral, aortic, or lower extremity). A total of 21.6% had cognitive impairment according to the prespecified cutoff (MMSE < 26). Overall, the odds of cognitive impairment increased for each additional vascular territory affected by atherosclerosis [adjusted odds ratio 1.76, 95% confidence interval (CI) 1.21-2.57, p = 0.003]. Furthermore, there was evidence for an interaction between vascular disease and chronic kidney disease (CKD). The odds of cognitive impairment were not greater in the monoVD subgroup compared to those without any atherosclerosis, if CKD was absent (OR 0.98, 95% CI 0.48-2.10; p = 0.095), while the odds ratio (OR) of cognitive impairment with polyVD compared to no atherosclerosis was 2.71 (95% CI 1.10-6.92; p = 0.031). In contrast, in patients with CKD, both monoVD and polyVD were associated with significantly higher odds of cognitive impairment than no atherosclerosis.

CONCLUSIONS

PolyVD is associated with increased odds of cognitive impairment. MonoVD is associated with cognitive impairment only in the presence of CKD.

Acute Myocardial Infarction and Risk of Cognitive Impairment and Dementia: A Review

Cognitive impairment (CI) shares common cardiovascular risk factors with acute myocardial infarction (AMI), and is increasingly prevalent in our ageing population. Whilst AMI is associated with increased rates of CI, CI remains underreported and infrequently identified in patients with AMI. In this review, we discuss the evidence surrounding AMI and its links to dementia and CI, including pathophysiology, risk factors, management and interventions. Vascular dysregulation plays a major role in CI, with atherosclerosis, platelet activation, microinfarcts and perivascular inflammation resulting in neurovascular unit dysfunction, disordered homeostasis and a dysfunctional neurohormonal response. This subsequently affects perfusion pressure, resulting in enlarged periventricular spaces and hippocampal sclerosis. The increased platelet activation seen in coronary artery disease (CAD) can also result in inflammation and amyloid-β protein deposition which is associated with Alzheimer's Dementia. Post-AMI, reduced blood pressure and reduced left ventricular ejection fraction can cause chronic cerebral hypoperfusion, cerebral infarction and failure of normal circulatory autoregulatory mechanisms. Patients who undergo coronary revascularization (percutaneous coronary intervention or bypass surgery) are at increased risk for post-procedure cognitive impairment, though whether this is related to the intervention itself or underlying cardiovascular risk factors is debated. Mortality rates are higher in dementia patients with AMI, and post-AMI CI is more prevalent in the elderly and in patients with post-AMI heart failure. Medical management (antiplatelet, statin, renin-angiotensin system inhibitors, cardiac rehabilitation) can reduce the risk of post-AMI CI; however, beta-blockers may be associated with functional decline in patients with existing CI. The early identification of those with dementia or CI who present with AMI is important, as subsequent tailoring of management strategies can potentially improve outcomes as well as guide prognosis.

Data-driven physical actigraphy patterns relate to cognitive and vascular health in older adults

Health benefits of physical activity (PA) are well known; however, specific PA patterns that relate most strongly to cognitive aging outcomes are poorly understood. We characterized latent profiles of PA among older adults and examined associations with cognition and vascular burden. 124 functionally normal older adults wore a Fitbit™ for 30 days. Daily average step count, sedentary time (0 steps/min), and high-intensity time (≥120 steps/min) were calculated. Participants completed neurocognitive testing assessing cognitive domains of executive functioning and memory; medical history, from which vascular burden (i.e., a count of cardiovascular conditions) was calculated; and brain MRI (n = 44). Subgroups with similar PA patterns were identified via latent profile analysis. Three latent PA classes emerged: Class 1Low PA (n = 49), Class 2Average PA (n = 59), and Class 3High-intensity PA (n = 16). PA class related to executive functioning and vascular burden, driven by better outcomes in Class 3 than Class 1. Sex-stratified analyses revealed these associations were strongest in males. Post hoc analyses showed a positive association between high-intensity PA and white matter integrity among males. High-intensity PA related to better cognitive and vascular health, particularly among males. Findings inform physical activity-specific and person-specific recommendations for optimal cognitive aging.

Roles of physical activity and diet in cognitive aging: is more better?

Objective: To determine the synergistic effects of nutrition, specifically adherence to the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet, and physical activity on cognition and brain outcomes in a cross-sectional healthy aging cohort. Methods: A total of 132 adults (age range 52-91; Clinical Dementia Rating = 0) from the UCSF Brain Aging Project completed a 15-item MIND diet food frequency questionnaire and an 11-item self-report measure of weekly physical activity (Physical Activity Scale [PASE]). Cognitive outcomes included executive functioning, episodic memory, and language. Neuroimaging outcomes consisted of total grey matter volume and total white matter volume, adjusted for total intracranial volumes. All regression interaction models adjusted for age, sex, education, and a composite vascular burden score. Results: There was a significant interaction between PASE and MIND on executive functioning and total grey matter volume. Low levels of both related to disproportionately poorer cognitive and brain structural outcomes. Increasing levels of either, but not both, PASE or MIND related to better executive functioning and gray matter outcomes. For memory, language, and total white matter volume, the interaction between PASE and MIND showed the same directionality but did not reach statistical significance. Conclusions: Higher levels of physical activity associated with better executive functioning and gray matter volume, particularly when diet was poor. Similarly, higher levels of MIND diet adherence were associated with better brain and cognitive outcomes when physical activity was low. However, highest levels of physical activity and MIND diet together did not necessarily lead to disproportionately better cognitive and brain volume outcomes.

Statistical Approaches for the Analysis of Combined Health-Related Factors in Association with Adult Cognitive Outcomes: A Scoping Review

BACKGROUND

Dementia prevention is a global health priority, and there is emerging evidence to support associations between individual modifiable health behaviors and cognitive function and dementia risk. However, a key property of these behaviors is they often co-occur or cluster, highlighting the importance of examining them in combination.

OBJECTIVE

To identify and characterize the statistical approaches used to aggregate multiple health-related behaviors/modifiable risk factors and assess associations with cognitive outcomes in adults.

METHODS

Eight electronic databases were searched to identify observational studies exploring the association between two or more aggregated health-related behaviors and cognitive outcomes in adults.

RESULTS

Sixty-two articles were included in this review. Fifty articles employed co-occurrence approaches alone to aggregate health behaviors/other modifiable risk factors, eight studies used solely clustering-based approaches, and four studies used a combination of both. Co-occurrence methods include additive index-based approaches and presenting specific health combinations, and whilst simple to construct and interpret, do not consider the underlying associations between co-occurring behaviors/risk factors. Clustering-based approaches do focus on underlying associations, and further work in this area may aid in identifying at-risk subgroups and understanding specific combinations of health-related behaviors/risk factors of particular importance in the scope of cognitive function and neurocognitive decline.

CONCLUSION

A co-occurrence approach to aggregating health-related behaviors/risk factors and exploring associations with adult cognitive outcomes has been the predominant statistical approach used to date, with a lack of research employing more advanced statistical methods to explore clustering-based approaches.

Bacterial pneumonia and subsequent dementia risk: A nationwide cohort study

BACKGROUND

Bacterial pneumonia is associated with an increased risk of dementia. However, the association between different pathogens of bacterial pneumonia and the risk of dementia remains unclear.

METHODS

Using the Taiwan National Health Insurance Research Database, we recruited 11,712 patients with bacterial pneumonia and 11,120 controls between 1997 and 2012 and followed them up until the end of 2013. A diagnosis of dementia, Alzheimer's disease (AD), vascular dementia (VaD), and unspecified dementia were identified during the follow-up period. Cox regression analyses were performed with adjustments for confounders. Sensitivity analysis was conducted to exclude patients with prodromal dementia.

RESULTS

Patients with bacterial pneumonia were more likely to develop dementia (hazard ratio [HR]: 2.83, 95% confidence interval [CI]: 2.53-3.18), AD (HR: 2.44, 95% CI: 1.65-3.61), VaD (HR: 4.15, 95% CI: 3.20-5.38), and unspecified dementia (HR: 2.62, 95% CI: 2.29-3.00) compared with controls after adjusting for potential confounders. Subgroup pathogen analyses showed that the HR of AD was 3.85 (1.66-8.96) for Hemophilus, and the HR of VaD was 5.40 for Staphylococcus. The risks of dementia and VaD were associated with repeated hospitalization due to bacterial pneumonia in a dose-dependent manner. Sensitivity analyses after exclusion of the first three years or first five years of observation and after exclusion case enrollment before 2010 or 2008 showed consistent findings.

CONCLUSION

Different pathogens are associated with different risks of AD, VaD, and unspecified dementia. Further studies are necessary to investigate the underlying mechanisms of bacterial pneumonia and dementia.

The Relationship of Coronary Artery Calcium and Clinical Coronary Artery Disease with Cognitive Function: A Systematic Review and Meta-Analysis

AIM

Coronary artery disease (CAD) and cognitive impairment are common in the elderly, with evidence for shared risk factors and pathophysiological processes. The coronary artery calcium (CAC) score is a marker of subclinical CAD, which may allow early detection of individuals prone to cognitive decline. Prior studies on associations of CAC and clinical CAD with cognitive impairment had discrepant results. This systematic review aims to evaluate the association of (sub)clinical CAD with cognitive function, cognitive decline, and diagnosis of mild cognitive impairment (MCI) or dementia.

METHODS

A systematic search was conducted in MEDLINE, Embase, and Web of Science until February 2019, supplemented with citations tracking. Two reviewers independently screened studies and extracted information including odds ratios (ORs) and hazard ratios (HRs).

RESULTS

Forty-six studies, 10 on CAC and 36 on clinical CAD, comprising 1,248,908 participants were included in the systematic review. Studies about associations of (sub)clinical CAD with cognitive function and cognitive decline had heterogeneous methodology and inconsistent findings. Two population-based studies investigated the association between CAC and risk of dementia over 6-12.2 years using different CAC scoring methods. Both found a tendency toward higher risk of dementia as CAC severity increased. Meta-analysis in 15 studies (663,250 individuals) showed an association between CAD and MCI/dementia (pooled OR 1.32, 95%CI 1.17-1.48) with substantial heterogeneity (I²=87.0%, p＜0.001). Pooled HR of CAD for incident MCI/dementia over 3.2-25.5 years in six longitudinal studies (70,060 individuals) was 1.51 (95%CI 1.24-1.85), with low heterogeneity (I²=14.1%, p=0.32). Sensitivity analysis did not detect any study that was of particular influence on the pooled OR or HR.

CONCLUSIONS

Limited evidence suggests the CAC score is associated with risk of dementia. In clinical CAD, risk of MCI and dementia is increased by 50%, as supported by stronger evidence.

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.

Coronary heart disease and risk for cognitive impairment or dementia: Systematic review and meta-analysis

AIMS/HYPOTHESIS

Accumulating evidence suggests an association between coronary heart disease and risk for cognitive impairment or dementia, but no study has systematically reviewed this association. Therefore, we summarized the available evidence on the association between coronary heart disease and risk for cognitive impairment or dementia.

METHODS

Medline, Embase, PsycINFO, and CINAHL were searched for all publications until 8th January 2016. Articles were included if they fulfilled the inclusion criteria: (1) myocardial infarction, angina pectoris or coronary heart disease (combination of both) as predictor variable; (2) cognition, cognitive impairment or dementia as outcome; (3) population-based study; (4) prospective (≥1 year follow-up), cross-sectional or case-control study design; (5) ≥100 participants; and (6) aged ≥45 years. Reference lists of publications and secondary literature were hand-searched for possible missing articles. Two reviewers independently screened all abstracts and extracted information from potential relevant full-text articles using a standardized data collection form. Study quality was assessed with the Newcastle-Ottawa Scale. We pooled estimates from the most fully adjusted model using random-effects meta-analysis.

RESULTS

We identified 6,132 abstracts, of which 24 studies were included. A meta-analysis of 10 prospective cohort studies showed that coronary heart disease was associated with increased risk of cognitive impairment or dementia (OR = 1.45, 95%CI = 1.21-1.74, p<0.001). Between-study heterogeneity was low (I2 = 25.7%, 95%CI = 0-64, p = 0.207). Similar significant associations were found in separate meta-analyses of prospective cohort studies for the individual predictors (myocardial infarction, angina pectoris). In contrast, meta-analyses of cross-sectional and case-control studies were inconclusive.

CONCLUSION/INTERPRETATION

This meta-analysis suggests that coronary heart disease is prospectively associated with increased odds of developing cognitive impairment or dementia. Given the projected worldwide increase in the number of people affected by coronary heart disease and dementia, insight into causal mechanisms or common pathways underlying the heart-brain connection is needed.