Carotid Intima-Media Thickness and Cognitive Function in Elderly Women: A Population-Based Study

Carotid Intima-Media Thickness (cIMT) and Cognitive Performance: A Population-Based Cross-Sectional Study From North India

INTRODUCTION

Atherosclerosis has been shown to impact cognitive impairment, with most of the evidence originating from European, African, or East Asian populations that have employed carotid intima-media thickness (cIMT) as a biomarker for atherosclerosis. Vascular disease is related to dementia/cognitive decline. There is no community-based study from India that has looked at the association of cIMT with cognitive performance.

METHODS

In this cross-sectional study between December 2014 and 2019, we recruited 7505 persons [(mean age 64.6 (9.2) y) and 50.9% women] from a community-dwelling population in New Delhi. These persons underwent carotid ultrasound to quantify cIMT and a cognitive test battery that tapped into memory, processing speed, and executive function. We also computed the general cognitive factor (g-factor), which was identified as the first unrotated component of the principal component analysis and explained 37.4% of all variances in the cognitive tests. We constructed multivariate linear regression models adjusted for age, sex, education, and cardiovascular risk factors. Additional adjustment was made for depression, anxiety, and psychosocial support in the final model.

RESULTS

We found a significant association of higher cIMT with worse performance in general cognition (β=-0. 01(95% CI: -0.01; -0.01); P<0.001), processing speed (β=-0.20; 95% CI: -0.34; -0.07); P=0.003), memory (β=-0.29; 95% CI: -0.53; -0.05); P=0.016), and executive function (β=-0.54; 95% CI: -0.75; -0.33); P=<0.001). There was no statistically significant association of cIMT with Mini-Mental Status Examination score (β=0.02; 95% CI: -0.34; 0.40; 0.89).

CONCLUSION

The cross-sectional study found significant associations of increased cIMT with worse performance in global cognition, information processing, memory, and executive function.

Is carotid artery atherosclerosis associated with poor cognitive function assessed using the Mini-Mental State Examination? A systematic review and meta-analysis

OBJECTIVES

To determine associations between carotid atherosclerosis assessed by ultrasound and the Mini-Mental State Examination (MMSE), a measure of global cognitive function.

DESIGN

Systematic review and meta-analysis.

METHODS

MEDLINE and EMBASE databases were searched up to 1 May 2020 to identify studies assessed the associations between asymptomatic carotid atherosclerosis and the MMSE. Studies reporting OR for associations between carotid plaque or intima-media thickness (cIMT) and dichotomised MMSE were meta-analysed. Publication bias of included studies was assessed.

RESULTS

A total of 31 of 378 reviewed articles met the inclusion criteria; together they included 27 738 participants (age 35-95 years). Fifteen studies reported some evidence of a positive association between measures of atherosclerosis and poorer cognitive performance in either cross-sectional or longitudinal studies. The remaining 16 studies found no evidence of an association. Seven cross-sectional studies provided data suitable for meta-analysis. Meta-analysis of three studies that assessed carotid plaque (n=3549) showed an association between the presence of plaque and impaired MMSE with pooled estimate for the OR (95% CI) being 2.72 (0.85 to 4.59). An association between cIMT and impaired MMSE was reported in six studies (n=4443) with a pooled estimate for the OR (95% CI) being 1.13 (1.04 to 1.22). Heterogeneity across studies was moderate to small (carotid plaque with MMSE, I2=40.9%; cIMT with MMSE, I2=4.9%). There was evidence of publication bias for carotid plaque studies (p=0.02), but not cIMT studies (p=0.2).

CONCLUSIONS

There is some, limited cross-sectional evidence indicating an association between cIMT and poorer global cognitive function assessed with MMSE. Estimates of the association between plaques and poor cognition are too imprecise to draw firm conclusions and evidence from studies of longitudinal associations between carotid atherosclerosis and MMSE is limited.

PROSPERO REGISTRATION NUMBER

CRD42021240077.

Intima Media Thickness and Cognitive Function Among Adults: Meta-Analysis of Observational and Longitudinal Studies

Background

Carotid structural changes measured by intima media thickness (IMT) have been related to cognitive complaints during aging. Therefore, the aims of this meta‐analysis were (1) to elucidate the relationship between vascular status, measured as IMT, and cognitive domains distinguishing between global cognition, executive functions, memory and attention; and (2) to explore whether demographic (ie, age and sex), clinical (ie, body mass index and IMT baseline values), and procedure characteristics influence this association.

Methods and Results

We performed a systematic review of MEDLINE (via PubMed), Scopus, and Web of Science databases from their inception to June 2021. Studies meeting the following inclusion criteria were included: (1) the participants were adults; (2) the exposure was carotid IMT; (3) the outcome was cognitive function, including global cognition, executive function, memory, and attention measured using standardized tests; and (4) the study design was cross‐sectional or longitudinal including unadjusted and adjusted analyses. A total of 19 cross‐sectional and 15 longitudinal studies were included and demographic (age and sex), clinical (body mass index and baseline IMT values), and procedure characteristics were analyzed as potential mediator or moderators of the association.

Conclusions

Our data support negative associations between IMT and cognitive function in cross‐sectional studies. The association between IMT and cognition lost significance in longitudinal studies and when controlling for covariates in cross‐sectional studies. Finally, the strength of these associations seems not to be modified by age, sex, body mass index, and baseline IMT values. This systematic review and meta‐analysis adds to the evidence supporting the use of IMT as a measure for identifying patients at risk of cognitive decline.

Carotid intima-media thickness and risk of mild cognitive impairment: A systematic review and meta-analysis

Mild cognitive impairment (MCI) is an early phase of cognitive decline signalling the beginning of severe neurological diseases. Carotid intima-media thickness (cIMT) has shown some correlation with MCI development. This study was conducted to investigate the impact of elevated cIMT on the risk of MCI in adults. A literature search was conducted in PubMed, EMBASE, Cochrane Library, Scopus, Google Scholar and CINAHL databases till 30 July 2021, with keywords: ('Carotid Intima-Media Thickness' OR 'cIMT' OR 'IMT' AND 'Cognitive Impairment' OR 'Cognition' OR 'Cognitive Decline' AND 'Mild Cognitive Impairment' OR 'MCI'). Pooled standardized mean difference (SMD)/odds ratio (OR) and 95% confidence interval (CI) were determined for factor-disease association using either fixed (when I² <50%) or random effect (when I² >50%) models. Eight studies involving 1,585 MCI cases and 6,700 normal subjects were included in our meta-analysis which showed no significant association of increased cIMT with the risk of MCI [SMD 1.17, 95% CI -0.09 to 2.42]. However, sensitivity analysis revealed an outlier study significantly affecting the effect size. On omitting the outlier study, the re-evaluated meta-analysis revealed a significant association of cIMT with the risk of MCI [SMD 0.52, 95% CI 0.26 to 0.78]. This significant association was also observed during subgroup analysis in Caucasian population [SMD 0.65, 95% CI 0.13 to 1.18] but not in Asian population [SMD 0.39, 95% CI -0.01 to 0.79]. Elevated cIMT poses a potential risk for MCI. However, more population-based studies are required to corroborate these findings.

Pleiotropic effects between cardiovascular disease risk factors and measures of cognitive and physical function in long-lived adults

Cardiovacular disease (CVD) is the leading cause of death among older adults and is often accompanied by functional decline. It is unclear what is driving this co-occurrence, but it may be behavioral, environmental and/or genetic. We used a family-based study to estimate the phenotypic and shared genetic correlation between CVD risk factors and physical and cognitive functional measures. Participants (n = 1,881) were from the Long Life Family Study, which enrolled families based on their exceptional longevity (sample mean age = 69.4 years, 44% female). Cardiovascular disease risk factors included carotid vessel measures [intima-media thickness and inter-adventitial diameter], obesity [body mass index (BMI) and waist circumference], and hypertension [systolic and diastolic blood pressures]. Function was measured in the physical [gait speed, grip strength, chair stand] and cognitive [digital symbol substitution test, retained and working memory, semantic fluency, and trail making tests] domains. We used SOLAR to estimate the genetic, environmental, and phenotypic correlation between each pair adjusting for age, age², sex, field center, smoking, height, and weight. There were significant phenotypic correlations (range |0.05–0.22|) between CVD risk factors and physical and cognitive function (all P < 0.05). Most significant genetic correlations (range |0.21–0.62|) were between CVD risk factorsand cognitive function, although BMI and waist circumference had significant genetic correlation with gait speed and chair stand time (range |0.29–0.53|; all P < 0.05). These results suggest that CVD risk factors may share a common genetic-and thus, biologic-basis with both cognitive and physical function. This is particularly informative for research into the genetic determinants of chronic disease.

Subclinical Carotid Artery Atherosclerosis and Cognitive Function: A Mini-Review

Carotid artery atherosclerosis, the result of a multitude of vascular risk factors, is a promising marker for use in risk stratification. Recent evidence suggests that carotid artery atherosclerosis affects cognitive function and is an independent risk factor for the development of cognitive impairment. Both atherosclerosis and cognitive impairment develop over a prolonged period (years), and due to the aging population, markers to identify persons at risk are needed. Carotid artery atherosclerosis can easily be visualized using non-invasive ultrasound, potentially enabling early and intensified risk factor management to preserve cognitive function or delay further decline. However, the burden of atherosclerosis and temporal exposure required to pose a risk of cognitive impairment is unclear. This mini-review aims to explore the available evidence on the association between carotid atherosclerosis and cognition, and furthermore identify the remaining gaps in knowledge.

Risk factors for delayed-onset dementia after stroke or transient ischemic attack-A five-year longitudinal cohort study

BACKGROUND

Stroke not only substantially increases the risk of incident dementia early after stroke but also the risk remains elevated years after.

AIM

We aimed to determine the risk factors of dementia onset more than three to six months after stroke or transient ischemic attack.

METHODS

This is a single-center prospective cohort study. We recruited consecutive subjects with stroke/transient ischemic attack without early-onset dementia. We conducted an annual neuropsychological assessment for five years. We investigated the association between baseline demographic, clinical, genetic (APOEɛ4 allele), and radiological factors as well as incident recurrent stroke with delayed-onset dementia using Cox proportional hazards models.

RESULTS

In total, 1007 patients were recruited, of which 88 with early-onset dementia and 162 who lost to follow-ups were excluded. Forty-nine (6.5%) out of 757 patients have incident delayed-onset dementia. The presence of ≥3 lacunes, history of ischemic heart disease, history of ischemic stroke, and a lower baseline Hong Kong version of the Montreal Cognitive Assessment (MoCA) score were significantly associated with delayed-onset dementia. APOEɛ4 allele, medial temporal lobe atrophy, and recurrent stroke were not predictive.

CONCLUSION

The presence of ≥3 lacunes, history of ischemic heart disease, history of ischemic stroke, and a lower baseline MoCA score are associated with delayed-onset dementia after stroke/transient ischemic attack.

Cerebrovascular Pathology and Responsiveness to Treatment in Alzheimer's Disease: A Systematic Review

INTRODUCTION

Responsiveness to treatment with cholinesterase inhibitors (ChEIs) is difficult to predict in Alzheimer's disease (AD). In the current review, vascular burden is considered as a potential moderator of treatment responsiveness. Cerebrovascular burden co-occurs in at least 30% of AD brains, although it is debated if vascular pathology plays a causal or synergistic role in AD pathogenesis. Vascular burden, therefore, could potentially limit response to treatment due to limited brain reserve or foster treatment efficacy as those with vascular pathology may represent a subgroup with comparable clinical expression but less progressed AD neurodegeneration.

METHODS

A systematic search of Web of Science, Pubmed, Scopus and EthoS identified 32 papers which met the criteria for inclusion. Association of treatment response and vascular burden across five broad markers are discussed: cerebral hypoperfusion, intima-media thickness, white matter changes, cerebral microbleeds and co-existing diagnosis of cerebrovascular disease.

RESULTS

Analysis of frontal regional cerebral blood flow and intima-media thickness may have predictive ability to distinguish those with AD who may respond optimally to short-term treatment with ChEIs. The impact of white matter changes is less consistent; the majority of studies demonstrates no association with treatment response and those that do implicate changes in executive functioning. There is preliminary evidence that deep cerebral microbleeds limit treatment response in subcortical cognitive domains, but this finding requires replication. The use of diagnosis of co-occurring cerebrovascular disease yields no robust variability in response to ChEIs in AD.

CONCLUSION

There is limited evidence that markers of cerebral hypoperfusion, intima-media thickness and cerebral microbleeds moderate response to ChEIs. Findings for other markers of vascular burden are less consistent and do not support any moderating effect.

Double-task exercise programmes to strengthen cognitive and vascular health in older adults at risk of cognitive decline: protocol for a randomised clinical trial

INTRODUCTION

Cognitive and physical declines are frequent causes of disability among older adults (OAs) in Mexico that imposes significant burden on the health system and OAs' families. Programmes to prevent or delay OAs' cognitive and physical decline are scarce.

METHODS AND ANALYSIS

A double-blind randomised clinical trial will be conducted. The study will aim to evaluate two 24-week double-task (aerobic and cognitive) square-stepping exercise programmes for OAs at risk of cognitive decline-one programme with and another without caregiver participation-and to compare these with an aerobic-balance-stretching exercise programme (control group). 300 OAs (100 per group) affiliated with the Mexican Institute of Social Security (IMSS) between 60 and 65 years of age with self-reported cognitive concerns will participate. They will be stratified by education level and randomly allocated to the groups. The intervention will last 24 weeks, and the effect of each programme will be evaluated 12, 24 and 52 weeks after the intervention. Participants' demographic and clinical characteristics will be collected at baseline. The outcomes will include: (1) general cognitive function; (2) specific cognitive functions; (3) dual-task gait; (4) blood pressure; (5) carotid intima-media thickness; (6) OAs' health-related quality of life; and (7) caregiver burden. The effects of the interventions on each outcome variable will be examined using a repeated-measures analysis of variance (ANOVA), with study groups as the between-subjects variable and time as the within-subject variable.

ETHICS AND DISSEMINATION

The study was approved by the IMSS Ethics and Research Committees (registration number: 2018-785-095). All participants will sign a consent form prior to their participation. The study results will be disseminated to the IMSS authorities, healthcare providers and the research community.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT04068376).

Healthy Lifestyle During the Midlife Is Prospectively Associated With Less Subclinical Carotid Atherosclerosis: The Study of Women's Health Across the Nation

Background

Measures of subclinical atherosclerosis are predictors of future cardiovascular outcomes as well as of physical and cognitive functioning. The menopausal transition is associated with accelerated progression of atherosclerosis in women. The prospective association between a healthy lifestyle during the midlife and subclinical atherosclerosis is unclear.

Methods and Results

Self‐reported data on smoking, diet, and physical activity from 1143 women in the Study of Women's Health Across the Nation were used to construct a 10‐year average Healthy Lifestyle Score (HLS) during the midlife. Markers of subclinical atherosclerosis were measured 14 years after baseline and included common carotid artery intima‐media thickness (CCA‐IMT), adventitial diameter (CCA‐AD), and carotid plaque. The associations of average HLS with CCA‐IMT and CCA‐AD were estimated using linear models; the association of average HLS with carotid plaque was estimated using cumulative logit models. Average HLS was associated with smaller CCA‐IMT and CCA‐AD in the fully adjusted models (P=0.0031 and <0.001, respectively). Compared with participants in the lowest HLS level, those in the highest level had 0.024 mm smaller CCA‐IMT (95% confidence interval: −0.048, 0.000), which equals 17% of the SD of CCA‐IMT, and 0.16 mm smaller CCA‐AD (95% confidence interval: −0.27, −0.04), which equals 24% of the SD of CCA‐AD. Among the 3 components of the HLS, abstinence from smoking had the strongest association with subclinical atherosclerosis.

Conclusions

Healthy lifestyle during the menopausal transition is associated with less subclinical atherosclerosis, highlighting the growing recognition that the midlife is a critical window for cardiovascular prevention in women.

Carotid artery plaque detected on ultrasound is associated with impaired cognitive state in the elderly: A population-based study in Wakiso district, Uganda

Carotid artery disease which includes carotid artery stenosis, plaques, clots and increased intima media thickness, have been reported by many studies to be associated with dementia. Dementia is an end stage of usually asymptomatic cognitive impairment. Risk factors of carotid artery disease include; age, atherosclerosis, arteriosclerosis, shorter years in school, history of hypertension, diabetes mellitus, stroke and depression. This study set out to determine the prevalence of abnormal carotid ultrasound findings and their association with cognitive function among the adults ≥60 years in Wakiso district, Uganda in 2018. A total of 210 participants were included. Carotid artery stenosis, presence of plaque, stenosis and intima-media thickness were assessed by ultrasound. Cognitive status was assessed using a Mini Mental State Exam (MMSE) test. The prevalence of plaque was 21.4%. Variables which included; presence of plaque, age, education, gender, marital status, whether participant stayed alone or with someone else, care for self, occupation status, division of staying and history of smoking. The presence of plaque was associated with an abnormal cognitive function at both univariate and multivariate analysis with respective OR = 3.8 (95% CI = 1.90-7.54, p-value = 0.0001) and OR = 3.4 (95% CI = 1.38-8.15, p-value = 0.007). The cognitive function distribution was 43.8%, 19%, 34.3% and 2.9% within the normal, mild, moderate, and severe cognitive function status respectively. This study showed that prevalence of carotid artery plaque was high in this elderly population in Wakiso district Uganda. Also, carotid artery plaque was associated with abnormal cognitive function.

Carotid Flow Velocities and Blood Pressures Are Independently Associated With Cognitive Function

BACKGROUND

Few studies simultaneously addressed associations between carotid flow velocities, blood pressure (BP), and cognitive function.

MATERIALS AND METHODS

Subject without dementia (N = 1,684) underwent measurements of BP and biochemical markers. Mini-Mental State Examination (MMSE) and comprehensive neuropsychological tests were used to evaluate cognitive function. Peak systolic velocity (PSV) and end-diastolic velocity (EDV) were measured in common and internal carotid artery. Subjects with MMSE score of ≤24 (25th percentile) was defined as low MMSE. Multivariable linear and logistic regression were used to evaluate the relationship of cognitive function with carotid flow velocities and BP.

RESULTS

Carotid flow velocities (PSV: standardized β = 0.067, P = 0.0009; and EDV: standardized β = 0.067, P = 0.0021) and systolic blood pressure (standardized β = -0.061, P = 0.005) were positively and negatively associated with MMSE, respectively, in the model with adjustments for age, sex, educational attainment, nutritional status, and smoking. Similar trends were noted for the associations between flow velocities and different neuropsychological tests. By multivariable logistic regression, the group with the lowest quartile (<25th percentile) of flow velocities had increased probability of low MMSE (odds ratio: 1.538; 95% confidence intervals: 1.142 to 2.071, P = 0.0046 for PSV; and odds ratio: 1.699; 95% confidence intervals: 1.233 to 2.341; P = 0.0012 for EDV), compared to those with the highest quartile (≥75th) flow velocities.

CONCLUSION

Both low carotid flow velocity and high BP were independently and comparably associated with cognitive dysfunction.

Associations of Common Genetic Variants on IL-17 Genes and Carotid Intima-Media Thickness

AIM

Atherosclerosis is a chronic inflammatory process of the arterial wall and carotid intima-media thickness (cIMT) is regarded as its early marker. Several members of the IL-17 family are involved in pro-inflammatory functions. The specific aim of the study was to explore the relationships of common genetic variants on IL-17 genes with cIMT thickening.

METHODS

In the discovery stage, 146 SNPs on 11 IL-17 genes were screened for their relationships with cIMT by a case-control study that enrolled 284 and 464 subjects who had thicker and normal cIMT, respectively. Findings were replicated by an independent case-control study that enrolled 282 subjects who had thicker cIMT and 282 age-sex-matched subjects who had normal cIMT.

RESULTS

Among 134 eligible SNPs in the discovery study, only IL-17RC rs279545 was significantly correlated with cIMT (p=6.9×10^-5). The rs279545 and 2 nearby linked SNPs rs55847610 and rs3846167 were included in the validation study. We found that the rs279545^＊G, rs55847610^＊G, and rs3846167^＊C were correlated with significantly higher likelihoods of having thicker cIMT. The corresponding multivariate-adjusted ORs were 1.462 (95% CI: 1.055-2.027), 1.481 (95% CI:1.090-2.013), and 1.589 (95% CI: 1.147-2.200), respectively. Analyses of rs279545-rs55847610 haplotypes showed that the multivariate-adjusted OR for A-A haplotype was significantly decreased (OR=0.665, 95% CI: 0.487-0.908) and for G-G haplotype was significantly increased (OR=1.539, 95% CI: 1.097-2.161).

CONCLUSIONS

We first correlated cIMT, a preclinical clinical cardiovascular marker, with IL-17RC, the key molecule in the IL-17 signaling pathway. Our results indicated that IL-17RC may play critical role in the development of atherosclerotic diseases.

Carotid circumferential wall stress is not associated with cognitive performance among individuals in late middle age: The Maastricht Study

BACKGROUND AND AIMS

Arterial remodelling aims at normalising circumferential wall stress (CWS). Greater CWS in the carotid artery has previously been associated with the prevalence and severity of cerebral small vessel disease, a major cause of ageing-related cognitive decline. Here we test the hypothesis that greater carotid CWS is associated with poorer cognitive performance.

METHODS

We studied 722 individuals (60 ± 8 years, 55% men, 42.5% highly educated, blood pressure 137 ± 19/77 ± 11 mmHg, n = 197 with type 2 diabetes) who completed a neuropsychological assessment and underwent vascular ultrasound to measure the intima-media thickness (IMT) and interadventitial diameter (IAD) of the left common carotid artery at a plaque-free site. From IMT and IAD, lumen diameter (LD) was calculated. These structural measures were then combined with local carotid pulse pressure and brachial mean arterial pressure to obtain a measure of pulsatile (CWS_pulsatile) and average (CWS_mean) mechanical load on the vessel wall. Cognitive domains assessed were memory, executive function and attention, and processing speed.

RESULTS

After adjustment for age, sex, and education, regression analyses showed that neither CWS_pulsatile nor CWS_mean were associated with measures of cognitive performance (p-values ≥0.31). This null association did not differ by age or educational level, and was observed in both individuals with and without carotid plaque, diabetes and/or hypertension. In addition, none of the individual measures of carotid structure (i.e. IMT, IAD, and LD) was related to cognitive performance.

CONCLUSIONS

The present cross-sectional study shows that carotid CWS is not associated with cognitive performance, at least not among relatively highly educated individuals in late middle age with adequately controlled cardiovascular risk factors.

Carotid atherosclerosis promotes the progression of Alzheimer's disease: A three-year prospective study

Although cerebrovascular diseases have been considered as risk factors for cognitive decline and dementia, the associations between atherosclerosis and Alzheimer's disease (AD) have not been fully examined and remain controversial. The aim of this three-year prospective study was to investigate whether arotid artery atherosclerosis accelerates cognitive impairment in AD patients. The association of carotid intimal medial thickness (IMT) with prospective trajectories of cognitive function was assessed among 521 patients with light to moderate AD, and 437 AD patients were followed up annually for 3 years. Participants underwent initial carotid ultrasonography and repeated neuropsychological testing every year. Mixed-effects regression analyses were adjusted to estimate the effect of carotid IMT and other adjusting variables. The results of the present study indicated that carotid IMT was significantly associated with various measures of cognitive function. Furthermore, AD patients with higher carotid IMT values had a faster decline in cognitive scores in a variety of neuropsychological tests, particularly in verbal and non-verbal memory, semantic fluency and executive function. The present prospective study showed that carotid atherosclerosis is a predictive factor regarding the progression of cognitive impairment in AD patients, suggesting that early detection and treatment of vascular risk factors may prevent or at least postpone the evolution of the disease.

Association between Carotid Plaque and Cognitive Impairment in Chinese Stroke Population: The SOS-Stroke Study

We aimed to investigate the association between carotid plaques and cognitive impairment among patients with acute ischemic stroke, and to assess key clinical implications. In the Acute Ischemic Stroke Study, patients who received a cognitive testing and underwent complete carotid artery ultrasound scans were included. Cognitive function was measured by the mini-mental state examination. The cross-sectional relationships between cognitive impairment and carotid plaques were evaluated using multivariate logistic regression analysis. Of the 3116 patients included in this study, 826 (26.51%) patients were diagnosed with cognitive impairment. After adjusting for potential confounders, patients with ≥2 carotid plaques (odds ratio [OR] = 1.47; 95% confidence interval [CI]: 1.19–1.82), patients with ≥2 number of carotid arteries with plaque (OR = 1.48; 95% CI: 1.19–1.84) and patients with hypoechoic plaque (OR = 2.05; 95% CI: 1.24–3.38) are more likely to have cognitive impairment. In this acute ischemic stroke population, the number of carotid plaques, the number of carotid arteries with plaque and plaque stability are all associated with cognitive impairment.

Total atherosclerotic burden measured by magnetic resonance imaging is related to five-year decline in cognitive function

OBJECTIVE

The aim of this study was to explore whether total atherosclerotic burden is related to future decline in performance on cognitive tests.

METHODS

The total atherosclerotic burden (TAS) was assessed by whole-body magnetic resonance angiography (WBMRA) in 305 subjects at age 70 in the study Prospective Investigation of Vasculature in Uppsala Seniors (PIVUS). The mini-mental state examination (MMSE) and trail making tests (TMT) A and B were evaluated at ages 75 and 80 in 190 of those subjects. No subject with a diagnosis of dementia was included in the sample.

RESULTS

MMSE did not change during the 5 years of follow-up, while TMT A and B increased by 4 and 7 s, respectively. TAS at age 70 was significantly related to the individual change in TMT B (P<0·0001) between age 75 and 80, when adjusted for sex, education level, TMT B at age 75 and Framingham score at age 70. No such relationship was seen for the change in TMT A (P = 0·10). The relationship between TAS and the change in MMSE was of borderline significance (P = 0·025).

CONCLUSION

A relationship was found between the total atherosclerotic burden and future decline in performance on TMT B, highlighting a role of global atherosclerosis in the cognitive decline seen during ageing.

Thresholds of impaired cerebral hemodynamics that predict short-term cognitive decline in asymptomatic carotid stenosis

Subjects with asymptomatic carotid stenosis (ACS) may be at risk of cognitive impairment due to cerebral hypoperfusion. In this study, we aimed to detect a threshold of cerebral hemodynamics which is able to identify subjects at risk of cognitive deterioration. In subjects with ACS, cerebral vasomotor reactivity (CVR) was assessed with the breath-holding index (BHI) transcranial Doppler-based method. Cognitive deterioration was defined as a decrease in the MMSE score by ≥2 points after one year. In order to define the threshold of impaired BHI, a ROC curve analysis was performed adopting the binary difference of MMSE score as the outcome and continuous BHI as the testing variable. A total of 548 subjects completed the follow-up. Cognitive deterioration was observed in 119 patients (21.7%). The BHI value ipsilateral to the stenosis was the strongest predictor of cognitive deterioration among the variables tested. The best cut-point to discriminate between normal and abnormal BHI resulted ≤0.89. The post-test probability of cognitive deterioration for an abnormal BHI was 44%, while a normal BHI showed a post-test probability of 9% for the same outcome. The present investigation provides a threshold of reduced CVR that can be useful to identify subjects with ACS at risk of cognitive deterioration.

Association between subclinical carotid atherosclerosis, hyperhomocysteinaemia and mild cognitive impairment

OBJECTIVE

Evidence suggests that intima-media thickness (IMT) and plasma homocysteine (Hcy) levels are associated with one another, and both appear to be related to cognitive dysfunction. However, no connection between both factors taken together and mild cognitive impairment (MCI) has been established. This study analysed potential relationships between IMT, Hcy and MCI.

METHODS

We included 105 patients with MCI and 76 controls with no history of vascular disease. All participants underwent laboratory analyses, a carotid ultrasound, and clinical and neuropsychological assessment. We used the Mantel-Haenszel test (MHT), ANCOVA and multiple linear regression models (MLRM) to examine any associations between IMT, Hcy and cognitive state.

RESULTS

The MHT revealed a significant association between IMT and risk of MCI (z = 4.285, P < 0.0001). The OR for the upper quartile vs the lower quartile was 5.12 (95% CI: 2.12-12.36). MHT also showed a clear association between Hcy levels and risk of MCI (z = 3.01, P = 0.003). OR for the upper vs the lower quartile was 3.39 (95% CI: 1.41-8.12). Additionally, we found a correlation between IMT and Hcy (r = 0.162, P = 0.032).

CONCLUSIONS

Our results suggest that there is a connection between IMT, Hcy levels and presence of amnestic MCI in a population with no history of clinically manifest atherosclerosis. Furthermore, there is also a connection between the IMT and Hcy levels themselves.

Ankle-Brachial Index but Neither Intima Media Thickness Nor Coronary Artery Calcification is Associated With Mild Cognitive Impairment

BACKGROUND

Several studies have reported an association of atherosclerosis with mild cognitive impairment (MCI) and dementia independent of cardiovascular risk factors.

OBJECTIVE

To compare the cross-sectional association of the ankle-brachial index (ABI), intima media thickness (IMT), and coronary artery calcification (CAC) with MCI and its subtypes, amnestic MCI (aMCI) and non-amnestic MCI (naMCI) in the population-based Heinz Nixdorf Recall cohort study.

METHODS

4,086 participants performed a validated brief cognitive assessment at the first follow-up examination (2006-2008). MCI was diagnosed according to previously published criteria. Prevalence ratio (PR) regression models adjusted for age, gender, education, cardiovascular risk factors, and APOE genotype were used to compare the association of the ABI, the CAC-Agatston score and the IMT with MCI and its subtypes.

RESULTS

We identified 490 participants with MCI (mean age 66.1 ± 7.8, 46.9 % male, aMCI n = 249, naMCI n = 241) and 1,242 cognitively normal participants. A decreasing ABI (per 0.1) was significantly associated with a higher MCI prevalence in fully adjusted models (PR 1.06; 95% confidence interval (CI) 1.01-1.11), whereas an increasing CAC (log(CAC+1)) or IMT (per 0.1 mm) were not associated after adjustment. A decreasing ABI was also significantly associated with naMCI in fully adjusted models (PR 1.12; CI 1.03-1.21) but not with aMCI.

CONCLUSIONS

Our data show that the degree of generalized atherosclerosis as measured by the ABI is associated with MCI and with naMCI in a population-based cohort.

Endocrine Risk Factors for Cognitive Impairment

Cognitive impairment, including Alzheimer's disease and other kinds of dementia, is a major health problem in older adults worldwide. Although numerous investigators have attempted to develop effective treatment modalities or drugs, there is no reasonably efficacious strategy for preventing or recovering from cognitive impairment. Therefore, modifiable risk factors for cognitive impairment have received attention, and the growing literature of metabolic risk factors for cognitive impairment has expanded from epidemiology to molecular pathogenesis and therapeutic management. This review focuses on the epidemiological evidence for the association between cognitive impairment and several endocrine risk factors, including insulin resistance, dyslipidemia, thyroid dysfunction, vitamin D deficiency, and subclinical atherosclerosis. Researches suggesting possible mechanisms for this association are reviewed. The research investigating modifiable endocrine risk factors for cognitive impairment provides clues for understanding the pathogenesis of cognitive impairment and developing novel treatment modalities. However, so far, interventional studies investigating the beneficial effect of the "modification" of these "modifiable risk factors" on cognitive impairment have reported variable results. Therefore, well-designed, randomized prospective interventional studies are needed.

Vascular cognitive impairment and dementia

Vascular contributions to cognitive impairment are receiving heightened attention as potentially modifiable factors for dementias of later life. These factors have now been linked not only to vascular cognitive disorders but also Alzheimer's disease. In this chapter we review 3 related topics that address vascular contributions to cognitive impairment: 1. vascular pathogenesis and mechanisms; 2. neuropsychological and neuroimaging phenotypic manifestations of cerebrovascular disease; and 3. prospects for prevention of cognitive impairment of later life based on cardiovascular and stroke risk modification. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock.

Association between Carotid Artery Stenosis and Cognitive Impairment in Stroke Patients: A Cross-Sectional Study

To investigate potential associations between carotid artery stenosis and cognitive impairment among patients with acute ischemic stroke and to provide important clinical implications. We measured the degree of carotid artery stenosis and recorded the Mini-Mental State Examination score (MMSE) at admission in 3116 acute ischemic stroke patients. The association between carotid stenosis and cognitive impairment assessed by MMSE was tested using multivariate regression analysis. Other clinical variables of interest were also studied. After adjusting for age, gender, education level, marriage, alcohol use, tobacco use, physical activity, hypertension, diabetes, hypercholesterolemia, atrial fibrillation, myocardial infarction and NIHSS (National Institutes of Health Stroke Scale) score, we found that participants with high-grade stenosis of the carotid artery had a higher likelihood of cognitive impairment compared to those without carotid artery stenosis (OR = 1.49, 95%CI: 1.05–2.11, p<0.001). Left common carotid artery stenosis was associated with cognitive impairment in the univariate analysis, although this effect did not persist after adjustment for the NIHSS score. Cognitive impairment was associated with high-grade stenosis of the right carotid artery.

Evaluation and follow-up of cognitive functions in patients with minor stroke and transient ischemic attack

BACKGROUND AND PURPOSE

We aimed to examine the incidence of cognitive impairment among patients with stroke, the associated risk factors, progression of the cognitive impairment, and the association between the localization of the lesion(s) as detected by magnetic resonance imaging and the affected areas of cognitive function.

METHODS

A total of 40 patients over 18 years of age enduring a transient ischemic stroke or minor stroke within the past 3 months who had a minimum life expectancy of 1 year were included in this study. Same number, age-, and sex-matched individuals were included as controls. Patients were inquired on the presence of risk factors for stroke. A series of neuropsychological test batteries were administered in patient and control subjects for assessing cognitive functions. These tests were readministered at 6 and 12 months of follow-up to assess the progression of cognitive functions.

RESULTS

In this study among the patients with stroke, a significant impairment was seen in multiple cognitive functional tests following ischemic stroke as compared to control groups. The most common risk factors for stroke included hypertension (72.5%), hyperlipidemia, and cigarette smoking. The number of cognitive domains with an impairment was highest (in four cognitive tests) among those with coronary artery disease and atrial fibrillation, followed by those who had a >50% stenosis in Doppler (three cognitive tests). These findings suggest that the frequency of risk factors associated with stroke does not correlate with the frequency of risk factors associated with cognitive dysfunction. The stroke localizations were classified among the patients with stroke and reviewed in accordance with cognitive impairment.

CONCLUSION

Neuropsychological tests, clinical findings, and imaging studies should be used to document the poststroke cognitive dysfunction.

Intima-Media Thickness and Cognitive Function in Stroke-Free Middle-Aged Adults: Findings From the Coronary Artery Risk Development in Young Adults Study

BACKGROUND AND PURPOSE

The relationship between carotid artery intima-media thickness (IMT) and cognitive function in midlife remains relatively unexplored. We examined the association between IMT and cognitive function in a middle-aged epidemiological cohort of 2618 stroke-free participants.

METHODS

At the year 20 visit (our study baseline), participants from the Coronary Artery Risk Development in Young Adults study had IMT measured by ultrasound at the common carotid artery. Five years later, participants completed a cognitive battery consisting of the Rey Auditory-Verbal Learning Test of verbal memory, the Digit Symbol Substitution Test of processing speed, and the Stroop test of executive function. We transformed cognitive scores into standardized z scores, with negative values indicating worse performance.

RESULTS

Mean age at baseline was 45.3 years (SD, 3.6). Greater IMT (per 1 SD difference of 0.12 mm) was significantly associated with worse performance on all cognitive tests (z scores) in unadjusted linear regression models (verbal memory, -0.16; 95% confidence interval [CI], -0.20 to -0.13; processing speed, -0.23; 95% CI, -0.27 to -0.19; and executive function, -0.17; 95% CI, -0.20 to -0.13). In models adjusted for sociodemographics and vascular risk factors that lie earlier in the causal pathway, greater IMT remained negatively associated with processing speed (-0.06; 95% CI, -0.09 to -0.02; P, 0.003) and borderline associated with executive function (-0.03; 95% CI, -0.07 to 0.00; P, 0.07) but not with verbal memory.

CONCLUSIONS

We observed an association between greater IMT and worse processing speed-a key component of cognitive functioning-at middle age above and beyond traditional vascular risk factors. Efforts targeted at preventing early stages of atherosclerosis may modify the course of cognitive aging.

Carotid intima-media thickness is associated with the progression of cognitive impairment in older adults

BACKGROUND AND PURPOSE

We investigated the association between cardiovascular risk factors, including carotid intima-media thickness (CIMT), and future risk of mild cognitive impairment (MCI) and dementia in elderly subjects.

METHODS

We conducted a population-based prospective study as a part of the Korean Longitudinal Study on Health and Aging. Our study included 348 participants who were nondemented at the baseline (mean age, 71.7±6.3 years) and underwent cognitive evaluation at the 5-year follow-up. Baseline cardiovascular risk factors were compared according to the development of MCI or dementia during the study period.

RESULTS

At the baseline evaluation, 278 subjects were cognitively normal and 70 subjects had MCI. Diagnoses of cognitive function either remained unchanged or improved during the study period in 292 subjects (nonprogression group), whereas 56 subjects showed progression of cognitive impairment to MCI or dementia (progression group). The progression group exhibited a higher prevalence of hypertension and greater CIMT compared with the nonprogression group. Other baseline cardiovascular risk factors, including sex, body mass index, diabetes mellitus, insulin resistance, total cholesterol, waist-to-hip ratio, visceral fat, pulse wave velocity, and ankle-brachial index, were not significantly different between 2 groups. The association between greater baseline CIMT and the progression of cognitive impairment was maintained after adjustment for conventional baseline risk factors of cognitive impairment. Greater baseline CIMT was also independently associated with the development of MCI in the subjects whose baseline cognitive function was normal.

CONCLUSIONS

Greater baseline CIMT was independently associated with the risk of cognitive impairment, such as MCI and dementia in elderly subjects.

The role of carotid intima-media thickness in predicting longitudinal cognitive function in an older adult cohort

BACKGROUND AND PURPOSE

Carotid atherosclerosis is a risk factor for cerebrovascular disease in older adults. Although age-related cognitive decline has been associated with cerebrovascular disease, not much is known about the consequences of carotid atherosclerosis on longitudinal cognitive function. This study examines the longitudinal relationship between atherosclerosis and cognition in a sample of non-demented older subjects using baseline measurements of carotid intima media thickness (CIMT) and annual cognitive measures of executive function (EXEC) and verbal memory (MEM).

METHODS

Baseline measurements included CIMT derived from B-mode carotid artery ultrasound, structural T1-weighted images of white matter hypointensities (WMH), white matter lesions (WML), and cerebral infarct. Hypertension, low-density lipoprotein (LDL), diabetes, and waist to hip ratios (WHR) were included as covariates in our models to control for cerebrovascular risks and central adiposity. Annual composite scores of EXEC and MEM functions were derived from item response theory. Linear mixed models were used to model longitudinal cognitive change.

RESULTS

A significant inverse relationship was found between baseline CIMT and annual EXEC score, but not annual MEM score. Subjects included in the highest 4th quartile of CIMT showed a rate of annual decline in EXEC score that was significant relative to subjects in lower quartile groups (p<0.01). The relationship between the 4th quartile of CIMT and annual EXEC score remained significant after independently adjusting for imaging measures of white matter injury and cerebral infarct.

CONCLUSIONS

Older adult subjects with the highest index of CIMT showed an annual decline in EXEC scores that was significant relative to subjects with lower quartile measurements of CIMT, independent of our measures of white matter injury and cerebral infarct. Our findings suggest that elevated measures of CIMT may mark an atherosclerotic state, resulting in a decline in executive function and not memory in non-demented older adults.

Subclinical atherosclerotic calcification and cognitive functioning in middle-aged adults: the CARDIA study

OBJECTIVE

Cardiovascular risk factors in middle-age are associated with cognitive impairment and dementia in older age. Less is known about the burden of calcified subclinical atherosclerosis and cognition, especially in midlife. We examined the association of coronary artery and abdominal aortic calcified plaque (CAC and AAC, respectively) with cognitive functioning in middle-aged adults.

METHODS

This cross-sectional study included 2510 black and white adults (age: 43-55 years) without heart disease or stroke who completed a year 25 follow-up exam (2010-11) as part of the Coronary Artery Risk Development in Young Adults Study. CAC and AAC were measured with non-contrast computed tomography. Cognition was assessed with the Digit Symbol Substitution Test (DSST) (psychomotor speed), Stroop Test (executive function), and Rey Auditory Verbal Learning Test (RAVLT) (verbal memory).

RESULTS

A greater amount of CAC and AAC was associated with worse performance on each test of cognitive function after adjustment for age, sex, race, education, and study center. Associations were attenuated, but remained significant for the DSST and RAVLT following additional adjustment for vascular risk factors, including adiposity, smoking, alcohol use, dyslipidemia, hypertension, and diabetes. Compared to participants without CAC or AAC, those with both CAC and AAC, but not CAC or AAC alone was associated with lower DSST scores (p < 0.05).

CONCLUSIONS

In this community-based sample, greater subclinical atherosclerotic calcification was associated with worse psychomotor speed and memory in midlife. These findings underscore the importance of a life course approach to the study of cognitive impairment with aging.

Impact of metabolic syndrome on cognition and brain: a selected review of the literature

Metabolic syndrome (MetS), a clustering of risk factors for type 2 diabetes mellitus and cardiovascular disease, has been associated with cognitive dysfunction and brain abnormalities. This review describes the literature on the impact of MetS on brain and cognition and suggests directions for future research. A literature search for reports of MetS and cognition and brain imaging was conducted for both nonelderly adults and adolescents. No studies were found describing MetS and brain or cognition among adolescents; therefore, we also included studies investigating individual components of MetS in this age group. Most studies found associations between MetS and cognitive dysfunction. Multiple cognitive domains were affected by MetS in adults. In adolescents, the majority of findings were in executive functioning. Brain imaging literature in adults implicated MetS in ischemic stroke, white matter alterations, and altered brain metabolism. For adolescents, individual MetS factors were linked to volume losses in the hippocampus and frontal lobes. MetS negatively impacts cognitive performance and brain structure. Potential explanatory models include impaired vascular reactivity, neuroinflammation, oxidative stress, and abnormal brain lipid metabolism. We posit that insulin resistance-associated impairment in cerebrovascular reactivity is an important mechanism underlying brain deficits seen in MetS.

Vascular risk factors in Alzheimer's disease - preliminary report

BACKGROUND

The vascular risk factors are associated with an increased risk for vascular cognitive decline (VCD), but also with Alzheimer disease (AD).

OBJECTIVE

To investigate vascular risk factors in relation to AD and VCD, with a non-invasive neurosonological methods in a clinical settings.

RESULTS

A total of 296 patients with AD and 237 patients with VCD were included in the study. Hypertension, hyperlipidemia, diabetes mellitus, stroke, and white matter changes (p<0.001) were significantly more prevalent in VCD, although they were also present in AD patients. No statistically significant differences were obtained between groups regarding coronary disease, atrial fibrillation, average degree of carotid artery stenosis and carotid intima-media thickness (cITM). However, the patients with AD had carotid artery stenosis ">50%" (p=0.007) and present plaques (p<0.001) more frequently compared to vascular group. The significant associations between robust cognitive measure and vascular factors, diabetes mellitus, carotid stenosis, cITM, and type of plaques were identified only in VCD, but not in AD group.

CONCLUSIONS

The vascular risk factors were more prevalent in VCD group, although they were also present in AD. With few treatment options available in AD, it may be important not to neglect the vascular risk factors.

Carotid atherosclerosis and 10-year changes in cognitive function

BACKGROUND

Carotid atherosclerosis has been suggested to be involved in cognitive decline.

METHODS

The Epidemiology of Hearing Loss Study is a longitudinal study of aging among Beaver Dam residents, WI. In 1998-2000, carotid intima-media thickness (IMT) and plaque were measured by ultrasound; cognitive function was measured by the Mini-Mental State Examination (MMSE). Follow-up examinations were conducted in 2003-2005 and 2009-2010. Incidence of cognitive impairment was defined as an MMSE score <24 or reported physician-diagnosed dementia during the follow-up. In the last examination, five additional cognitive tests were added. The associations of carotid atherosclerosis with incident cognitive impairment and cognitive test performance ten years later were evaluated.

RESULTS

A total of 1651 participants (mean age 66.8 years, 41% men) without cognitive impairment at baseline were included in the incidence analysis. IMT was associated with incidence of cognitive impairment after multiple adjustments (hazard ratio: 1.09, p = 0.02 for each 0.1 mm increase in IMT). A total of 1311 participants with atherosclerosis data at baseline had the additional cognitive tests 10 years later. Larger IMT was associated with longer time to complete the Trail-Making Test-part B after multiple adjustments (0.1 mm IMT: 2.3 s longer, p = 0.02). Plaque was not associated with incident cognitive impairment or cognitive test performance 10 years later.

CONCLUSIONS

In this population-based longitudinal study, carotid IMT was associated with a higher risk of developing cognitive impairment during the 10-year follow-up, and was associated with poorer performance in a test of executive function 10 years later.

Atherosclerotic calcification relates to cognitive function and to brain changes on magnetic resonance imaging

BACKGROUND

Increasing evidence suggests a role of atherosclerosis in the pathogenesis of cognitive impairment and dementia. Calcification volume measured with computed tomography (CT) is a valid marker of atherosclerosis. This study investigates associations of atherosclerosis (measured using CT) at four locations with cognition and brain changes on magnetic resonance imaging (MRI).

METHODS

To quantify calcification volume, 2414 nondemented people from the Rotterdam Study underwent CT of the coronary arteries, aortic arch, extracranial carotid arteries, and intracranial carotid arteries. To assess global cognition and performance on memory, executive function, information processing speed, and motor speed, they also underwent neuropsychological tests. In a random subgroup of 844 participants, brain MRI was performed. Automated segmentation and quantification of brain MRI scans yielded brain tissue volumes in milliliters. Diffusion tensor imaging was used to measure the microstructural integrity of the white matter. Relationships of atherosclerotic calcification with cognition, brain tissue volumes, and diffusion tensor imaging measures were assessed with linear regression models and adjusted for relevant confounders.

RESULTS

With larger calcification volumes, lower cognitive scores were observed. When calcification volumes were larger, total brain volumes were also smaller. Specifically, larger coronary artery calcification volumes related to smaller gray matter volumes, and extracranial and intracranial carotid calcification volumes related to smaller white matter volumes. Larger calcification volume in all vessel beds was accompanied by worse microstructural integrity of the white matter.

CONCLUSIONS

Larger calcification volume is associated with worse cognitive performance. It also relates to smaller brain tissue volumes and worse white matter microstructural integrity, revealing possible mechanisms through which atherosclerosis may lead to poorer cognition.

Advanced asymptomatic carotid disease and cognitive impairment: an understated link?

Advanced carotid disease is known to be associated with symptomatic cerebrovascular diseases, such as stroke or transient ischemic attack (TIA), as well as with poststroke cognitive impairment. However, cognitive decline often occurs in patients with advanced carotid stenosis without clinically evident stroke or TIA, so it is also suspected to be an independent risk factor for dementia. Neurosonological methods enable simple and noninvasive assessment of carotid stenosis in patients at risk of advanced atherosclerosis. Cognitive status in patients diagnosed with advanced carotid stenosis is routinely not taken into consideration, although if cognitive impairment is present, such patients should probably be called symptomatic. In this paper, we discuss results of some most important studies that investigated cognitive status of patients with asymptomatic advanced carotid disease and possible mechanisms involved in the causal relationship between asymptomatic advanced carotid disease and cognitive decline.

Vascular contributions to cognitive impairment and dementia: a statement for healthcare professionals from the american heart association/american stroke association

BACKGROUND AND PURPOSE

This scientific statement provides an overview of the evidence on vascular contributions to cognitive impairment and dementia. Vascular contributions to cognitive impairment and dementia of later life are common. Definitions of vascular cognitive impairment (VCI), neuropathology, basic science and pathophysiological aspects, role of neuroimaging and vascular and other associated risk factors, and potential opportunities for prevention and treatment are reviewed. This statement serves as an overall guide for practitioners to gain a better understanding of VCI and dementia, prevention, and treatment.

METHODS

Writing group members were nominated by the writing group co-chairs on the basis of their previous work in relevant topic areas and were approved by the American Heart Association Stroke Council Scientific Statement Oversight Committee, the Council on Epidemiology and Prevention, and the Manuscript Oversight Committee. The writing group used systematic literature reviews (primarily covering publications from 1990 to May 1, 2010), previously published guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and, when appropriate, formulate recommendations using standard American Heart Association criteria. All members of the writing group had the opportunity to comment on the recommendations and approved the final version of this document. After peer review by the American Heart Association, as well as review by the Stroke Council leadership, Council on Epidemiology and Prevention Council, and Scientific Statements Oversight Committee, the statement was approved by the American Heart Association Science Advisory and Coordinating Committee.

RESULTS

The construct of VCI has been introduced to capture the entire spectrum of cognitive disorders associated with all forms of cerebral vascular brain injury-not solely stroke-ranging from mild cognitive impairment through fully developed dementia. Dysfunction of the neurovascular unit and mechanisms regulating cerebral blood flow are likely to be important components of the pathophysiological processes underlying VCI. Cerebral amyloid angiopathy is emerging as an important marker of risk for Alzheimer disease, microinfarction, microhemorrhage and macrohemorrhage of the brain, and VCI. The neuropathology of cognitive impairment in later life is often a mixture of Alzheimer disease and microvascular brain damage, which may overlap and synergize to heighten the risk of cognitive impairment. In this regard, magnetic resonance imaging and other neuroimaging techniques play an important role in the definition and detection of VCI and provide evidence that subcortical forms of VCI with white matter hyperintensities and small deep infarcts are common. In many cases, risk markers for VCI are the same as traditional risk factors for stroke. These risks may include but are not limited to atrial fibrillation, hypertension, diabetes mellitus, and hypercholesterolemia. Furthermore, these same vascular risk factors may be risk markers for Alzheimer disease. Carotid intimal-medial thickness and arterial stiffness are emerging as markers of arterial aging and may serve as risk markers for VCI. Currently, no specific treatments for VCI have been approved by the US Food and Drug Administration. However, detection and control of the traditional risk factors for stroke and cardiovascular disease may be effective in the prevention of VCI, even in older people.

CONCLUSIONS

Vascular contributions to cognitive impairment and dementia are important. Understanding of VCI has evolved substantially in recent years, based on preclinical, neuropathologic, neuroimaging, physiological, and epidemiological studies. Transdisciplinary, translational, and transactional approaches are recommended to further our understanding of this entity and to better characterize its neuropsychological profile. There is a need for prospective, quantitative, clinical-pathological-neuroimaging studies to improve knowledge of the pathological basis of neuroimaging change and the complex interplay between vascular and Alzheimer disease pathologies in the evolution of clinical VCI and Alzheimer disease. Long-term vascular risk marker interventional studies beginning as early as midlife may be required to prevent or postpone the onset of VCI and Alzheimer disease. Studies of intensive reduction of vascular risk factors in high-risk groups are another important avenue of research.

Carotid Atherosclerotic Disease and Cognitive Function: Mechanisms Identifying New Therapeutic Targets

The treatment of carotid atherosclerotic disease lies primarily in decreasing the risk of stroke. Many investigations have suggested carotid atherosclerotic disease as being independently associated with cognitive dysfunction, also supporting the notion that in sub-clinical stages, carotid atherosclerotic disease may not be truly silent. An improvement in cognitive function following revascularization approaches may be expected from the reduced embolism and the improved hemodynamics achieved. However, there are no strong data indicating a cognitive change after carotid angioplasty and stenting or carotid endarterectomy in patients who do not experience stroke complications and there is no evidence to support the performance of prophylactic revascularization procedures with the aim of preventing a cognitive decline in otherwise asymptomatic patients. Given the burden of dementia and its tragic implications for individuals and societies, the identification and treatment of such a preventable condition as carotid atherosclerotic disease should be considered. Therefore, it would be desirable in the design of future comparative studies of treatment strategies for carotid atherosclerotic disease to consider cognitive outcome as an endpoint.

Traffic-related air pollution and cognitive function in a cohort of older men

BACKGROUND

Traffic-related particles induce oxidative stress and may exert adverse effects on central nervous system function, which could manifest as cognitive impairment.

OBJECTIVE

We assessed the association between black carbon (BC), a marker of traffic-related air pollution, and cognition in older men.

METHODS

A total of 680 men (mean ± SD, 71 ± 7 years of age) from the U.S. Department of Veterans Affairs Normative Aging Study completed a battery of seven cognitive tests at least once between 1996 and 2007. We assessed long-term exposure to traffic-related air pollution using a validated spatiotemporal land-use regression model for BC.

RESULTS

The association between BC and cognition was nonlinear, and we log-transformed BC estimates for all analyses [ln(BC)]. In a multivariable-adjusted model, for each doubling in BC on the natural scale, the odds of having a Mini-Mental State Examination (MMSE) score ≤ 25 was 1.3 times higher [95% confidence interval (CI), 1.1 to 1.6]. In a multivariable-adjusted model for global cognitive function, which combined scores from the remaining six tests, a doubling of BC was associated with a 0.054 SD lower test score (95% CI, -0.103 to -0.006), an effect size similar to that observed with a difference in age of 1.9 years in our data. We found no evidence of heterogeneity by cognitive test. In sensitivity analyses adjusting for past lead exposure, the association with MMSE scores was similar (odds ratio = 1.3; 95% CI, 1.1 to 1.7), but the association with global cognition was somewhat attenuated (-0.038 per doubling in BC; 95% CI, -0.089 to 0.012).

CONCLUSIONS

Ambient traffic-related air pollution was associated with decreased cognitive function in older men.

Association of vascular health and neurocognitive performance in overweight adults with high blood pressure

The relationship between vascular health--including flow-mediated dilation (FMD) and intima medial thickness (IMT)--and neurocognitive performance was examined in a sample of 124 sedentary, middle-aged adults with high blood pressure (systolic blood pressure, SBP, 130-159 mmHg or diastolic blood pressure, DBP, 85-99 mmHg) who were overweight or obese (body mass index 25.0-39.99 kg/m²). Patients completed a neuropsychological test battery, including measures of executive function and psychomotor speed, and measures of IMT and FMD were obtained. Hierarchical multiple regression analyses were used to investigate the association between vascular measures and neurocognitive performance after controlling for demographic factors and cerebrovascular risk factors. Higher levels of FMD predicted better executive function (b = 0.90, p = .045). Greater IMT tended to be associated with slower psychomotor speed (b = -0.82, p = .084), with the effect attenuated after controlling for FMD. Impaired FMD is associated with worse neurocognitive functioning among overweight adults with high blood pressure.

Vascular risk factor detection and control may prevent Alzheimer's disease

The vascular hypothesis of Alzheimer disease (AD), first proposed by us in 1993, provides substantial evidence that suggests vascular risk factors (VRF) play a critical role in the development of cognitive decline and AD during aging. Cardiovascular and carotid artery disease, two major risk factors to AD, can conspire or independently induce chronic brain hypoperfusion (CBH) decades before any symptoms of cognitive impairment are expressed. The pathologic construct linking CBH to cognitive impairment and AD remains unclear but evidence shows that it may provide an opportunity to intervene in the prevention or delay of dementia onset. A preliminary randomized clinical study in cognitively healthy middle age individuals to undergo screening using carotid Doppler ultrasound, echocardiography and ankle-brachial index is proposed. These office tools are non-invasive, cost-effective, easily applied in one session and relatively accurate procedures with no inherent harmful effects. More importantly, ultrasound can help identify asymptomatic patients most likely to develop progressive cognitive decline due to persistent CBH secondary to progressive cardiovascular or carotid artery pathology. When these VRF are detected within the heart or carotid arteries, optimal medical treatment or management may be indicated to prevent or slow down further disease progression that fosters cognitive deterioration generated from such conditions. Secondary screening tools such as neuroimaging, neurocognitive testing and CSF markers may be used to confirm ultrasound findings. Prevention-by-detection of VRF and target treatment, if found effective, could significantly promote healthier mental and physical aging and lessen the socio-economic calamity anticipated from the growing prevalence of dementia.

Coronary artery calcium, brain function and structure: the AGES-Reykjavik Study

BACKGROUND AND PURPOSE

Several cardiovascular risk factors are associated with cognitive disorders in older persons. Little is known about the association of the burden of coronary atherosclerosis with brain structure and function.

METHODS

This is a cross-sectional analysis of data from the Age, Gene, Environment Susceptibility (AGES)-Reykjavik Study cohort of men and women born 1907 to 1935. Coronary artery calcification (CAC), a marker of atherosclerotic burden, was measured with CT. Memory, speed of processing, and executive function composites were calculated from a cognitive test battery. Dementia was assessed in a multistep procedure and diagnosed according to international guidelines. Quantitative data on total intracranial and tissue volumes (total, gray matter volume, white matter volume, and white matter lesion volume), cerebral infarcts, and cerebral microbleeds were obtained with brain MRI. The association of CAC with dementia (n=165 cases) and cognitive function in nondemented subjects (n=4085), and separately with MRI outcomes, was examined in multivariate models adjusting for demographic and vascular risk factors. Analyses tested whether brain structure mediated the associations of CAC to cognitive function.

RESULTS

Subjects with higher CAC were more likely to have dementia and lower cognitive scores, more likely to have lower white matter volume, gray matter volume, and total brain tissue, and to have more cerebral infarcts, cerebral microbleeds, and white matter lesions. The relations of cognitive performance and dementia to CAC were significantly attenuated when the models were adjusted for brain lesions and volumes.

CONCLUSIONS

In a population-based sample, increasing atherosclerotic load assessed by CAC is associated with poorer cognitive performance and dementia, and these relations are mediated by evidence of brain pathology.

Carotid- intima media thickness is independently associated with cognitive decline. The INVADE study

OBJECTIVES

Increased carotid intima-media thickness (C-IMT) is a non-invasive marker of atherosclerosis and predicts vascular events. Moreover, increasing evidence suggests an association between carotid atherosclerosis and cognitive decline. The purpose of this study is to investigate the relationship between C-IMT and the development of cognitive impairment in a large population-based sample.

METHODS

This study was based on the data of the participants of the INVADE (Intervention project on cerebrovascular diseases and dementia in the district of Ebersberg, Bavaria) project. Vascular risk factors, Geriatric depression scale (GDS) and "6 Item Cognitive Impairment Test" (6CIT) were evaluated at baseline and after 2 years. The relationship between C-IMT and cognitive impairment was analysed using multivariate logistic regression.

RESULTS

Complete baseline data were available in 3386 subjects (mean age 67.7 [95% confidence interval (CI): 67.5, 68.0] years, 41% male). During follow-up, 174 subjects developed a new cognitive impairment. In the subgroup without cognitive impairment at baseline a significant association between cognitive decline after 2 years and elevated C-IMT at baseline could be detected with a significantly higher baseline C-IMT in those with cognitive decline (0.87 mm vs. 0.78 mm; p < 0.0001). After adjustment for various risk factors only age, GDS baseline 6CIT and C-IMT were independently associated with the development of a new cognitive impairment.

CONCLUSIONS

Our data indicate that an increased carotid intima-media thickness predicts a cognitive decline in an elderly population without prevalent cognitive impairment.

Intima-media thickness and regional cerebral blood flow in older adults

BACKGROUND AND PURPOSE

The relationship between the thickness of the carotid intima (IMT) and brain function remains unclear in those without clinical manifestations of cerebrovascular disease. Understanding the neural correlates of this vascular measure is important in view of emerging evidence linking poorer cognitive performance with increased IMT in individuals without clinical cerebrovascular disease.

METHODS

Seventy-three participants in the Baltimore Longitudinal Study of Aging (70.9 years; SD, 7.3) were evaluated with carotid artery ultrasound and resting [(15)O]H(2)O positron emission tomography.

RESULTS

After adjusting for age, gender, and gray and white matter volumes in the regions where IMT is related to regional cerebral blood flow (rCBF), we found that higher IMT was associated with lower rCBF in lingual, inferior occipital, and superior temporal regions. Higher IMT was also associated with higher rCBF in medial frontal gyrus, putamen, and hippocampal-uncal regions (P=0.001). Whereas women had lower IMT (P=0.01) and mean arterial pressure (P=0.05) than men, they showed more robust associations between IMT and rCBF. The relationship between IMT and rCBF was only minimally affected by additional adjustment for mean arterial pressure.

CONCLUSIONS

IMT is related to patterns of resting rCBF in older adults without clinical manifestations of cerebrovascular disease, suggesting that there are regional differences in CBF that are associated with subclinical vascular disease.

Relationship between inflammatory markers, endothelial activation markers, and carotid intima-media thickness in HIV-infected patients receiving antiretroviral therapy

BACKGROUND

Human immunodeficiency virus (HIV)-infected patients are at increased risk of cardiovascular disease, which may be related to chronic inflammation and endothelial dysfunction despite virological control with antiretroviral therapy. The relationship between carotid intima-media thickness (IMT), a surrogate marker for cardiovascular disease, proinflammatory cytokines, and endothelial activation markers has not been fully explored in HIV-infected patients who are receiving antiretroviral therapy.

METHODS

We conducted a prospective, cross-sectional, observational study of treated HIV-infected patients and healthy control subjects to evaluate the relationship between carotid IMT, proinflammatory cytokines, endothelial activation biomarkers, and metabolic parameters in treated HIV-infected patients, compared with healthy control subjects.

RESULTS

We enrolled 73 HIV-infected patients and 21 control subjects. Common carotid artery and internal carotid artery IMT measurements, as well as tumor necrosis factor-alpha, high-sensitivity C-reactive protein, interleukin-6, myeloperoxidase, and soluble vascular cell adhesion molecule-1 levels were higher in the HIV-infected group. High-sensitivity C-reactive protein was the only biomarker that was positively correlated with carotid IMT in both groups. In the HIV-infected group, soluble vascular cell adhesion molecule-1 was positively correlated with all inflammatory cytokine levels. In multiple regression analysis, soluble vascular cell adhesion molecule-1, myeloperoxidase, and tumor necrosis factor-alpha levels were all associated with internal carotid artery IMT in the HIV-infected group, whereas age was associated with both common carotid artery and internal carotid artery IMT.

CONCLUSIONS

Enhanced endothelial activation, inflammation, and increased carotid IMT occur in HIV-infected patients despite antiretroviral therapy. Inflammatory markers are associated with endothelial activation, and both are associated with internal carotid artery IMT, supporting a potential role of inflammation in endothelial activation and cardiovascular disease in HIV infection.