Ankle-brachial index, cognitive impairment and cerebrovascular disease in a Chinese population

Correlation between ankle-brachial index and subtle cognitive decline

BACKGROUND

Subtle cognitive decline (SCD) is considered the early stage of Alzheimer's disease (AD) and is of great clinical significance for the prevention and treatment of AD. The ankle-brachial index (ABI) has been reported to be associated with cognitive impairment; however, there are few studies on the relationship between ABI and SCD.

METHODS

From August 2019 to April 2021, subjects were recruited to participate in a cognitive function test at the Shanghai Sixth People's Hospital. Based on the test results, 217 patients with SCD were selected as the experimental group and 259 patients with normal cognitive function were selected as the control group. The data of the two groups were compared, and the correlation between the ABI and cognitive decline was analyzed.

RESULTS

There were significant differences in age, sex, smoking status, hypertension, diabetes, triglycerides, serum creatinine, and ABI (p < .05)between the two groups. Logistic regression analysis showed that age, hypertension, diabetes, and ABI influenced cognitive decline(p < .05). After correcting for other factors, ABI was independently related to cognitive decline. Pearson's correlation analysis showed that a low ABI (<0.9) had a significant effect on memory and visual space of the cognitive domain (p < . 05).

CONCLUSIONS

ABI is significantly associated with SCD and may be a critical tool to predict early cognitive decline.

The Association between Ankle-Brachial Index/Pulse Wave Velocity and Cerebral Large and Small Vessel Diseases in Stroke Patients

(1) Background: The study investigated whether the ankle-brachial index (ABI) and pulse wave velocity (baPWV) could reflect the severity of small vessel disease (SVD) and large artery atherosclerosis (LAA). (2) Methods: A total of 956 consecutive patients diagnosed with ischemic stroke were prospectively enrolled from July 2016 to December 2017. SVD severity and LAA stenosis grades were evaluated via magnetic resonance imaging and carotid duplex ultrasonography. Correlation coefficients were calculated between the ABI/baPWV and measurement values. Multinomial logistic regression analysis was performed to determine predictive potential. (3) Results: Among the 820 patients included in the final analysis, the stenosis grade of extracranial and intracranial vessels was inversely correlated with the ABI (p < 0.001, respectively) and positively correlated with the baPWV (p < 0.001 and p = 0.004, respectively). Abnormal ABI, not baPWV, independently predicted the presence of moderate (adjusted odds ratio, aOR: 2.18, 95% CI: 1.31-3.63) to severe (aOR: 5.59, 95% CI: 2.21-14.13) extracranial vessel stenosis and intracranial vessel stenosis (aOR: 1.89, 95% CI: 1.15-3.11). Neither the ABI nor baPWV was independently associated with SVD severity. (4) Conclusions: ABI is better than baPWV in screening for and identifying the existence of cerebral large vessel disease, but neither test is a good predictor of cerebral SVD severity.

White matter network damage mediates association between cerebrovascular disease and cognition

To determine whether white matter network disruption mediates the association between MRI markers of cerebrovascular disease (CeVD) and cognitive impairment. Participants (n = 253, aged ≥60 years) from the Epidemiology of Dementia in Singapore study underwent neuropsychological assessments and MRI. CeVD markers were defined as lacunes, white matter hyperintensities (WMH), microbleeds, cortical microinfarcts, cortical infarcts and intracranial stenosis (ICS). White matter microstructure damage was measured as fractional anisotropy and mean diffusivity by tract based spatial statistics from diffusion tensor imaging. Cognitive function was summarized as domain-specific Z-scores.Lacunar counts, WMH volume and ICS were associated with worse performance in executive function, attention, language, verbal and visual memory. These three CeVD markers were also associated with white matter microstructural damage in the projection, commissural, association, and limbic fibers. Path analyses showed that lacunar counts, higher WMH volume and ICS were associated with executive and verbal memory impairment via white matter disruption in commissural fibers whereas impairment in the attention, visual memory and language were mediated through projection fibers.Our study shows that the abnormalities in white matter connectivity may underlie the relationship between CeVD and cognition. Further longitudinal studies are needed to understand the cause-effect relationship between CeVD, white matter damage and cognition.

Long-term neurobehavioral correlates of brain cortical microinfarcts in a memory clinic cohort in Singapore

BACKGROUND

Cortical cerebral microinfarcts are a small vessel disease biomarker underlying cognitive impairment and dementia. However, it is unknown whether cortical cerebral microinfarcts are associated with neuropsychiatric disturbances, and whether its effects are independent of conventional small vessel disease markers.

AIMS

We investigated the associations of cortical cerebral microinfarcts burden with incidence and progression of neuropsychiatric subsyndromes in a memory clinic cohort of elderly in Singapore.

METHODS

In this prospective cohort, 496 subjects underwent detailed neuropsychological and clinical assessments, 3T brain MRI, and Neuropsychiatric Inventory assessment at baseline and two years later. Cortical cerebral microinfarcts and other small vessel disease markers, including white matter hyperintensities, lacunes, and microbleeds, were graded according to established criteria. Neuropsychiatric symptoms (NPS) were clustered into subsyndromes of hyperactivity, psychosis, affective, and apathy following prior findings. Functional decline was determined using the clinical dementia rating (CDR) scale.

RESULTS

The presence of multiple cortical cerebral microinfarcts (≥2) was associated with higher total NPS scores (β = 4.19, 95% CI = 2.81-5.58, p < 0.001), particularly hyperactivity (β = 2.01, 95% CI = 1.30-2.71, p < 0.01) and apathy (β = 1.42, 95% CI = 0.65-2.18, p < 0.01) at baseline. Between baseline and year-2, multiple cortical cerebral microinfarcts were associated with accelerated progression in total NPS scores (β = 0.29, 95% CI = 0.06-0.53, p = 0.015), driven by hyperactivity (β = 0.45, 95% CI = 0.17-0.72, p < 0.01). Subjects with multiple cortical cerebral microinfarcts also had a faster functional decline, as measured with the CDR-sum-of-boxes scores, when accompanied with progression (β = 0.31, 95% CI = 0.11-0.51, p < 0.01) or hyperactivity in total NPS (β = 0.34, 95% CI = 0.13-0.56, p < 0.01).

CONCLUSION

Cortical cerebral microinfarcts are associated with incidence and progression of geriatric neurobehavioral disturbances, independent of conventional small vessel disease markers. The impact of incident cortical cerebral microinfarcts on neurocognitive and neuropsychiatric trajectories warrants further investigations.

Association between Ankle Brachial Index, Brachial-Ankle Pulse Wave Velocity, and Mild Cognitive Impairment in Patients with Acute Lacunar Infarction

BACKGROUND

The link between arterial stiffness and mild cognitive impairment (MCI) is receiving increasing attention, and the goal of this study was to explore the relationship among the ankle brachial index (ABI), brachial-ankle pulse wave velocity (Ba-PWV), and MCI in patients with acute lacunar infarction (ALI).

METHODS

A total of 103 hospitalized patients with ALI were divided into a non-MCI group (n = 41) and an MCI group (n = 62) according to their Montreal Cognitive Assessment (MoCA) scores. A binary logistic regression model was used to assess the association among ABI, Ba-PWV, and MCI after adjusting for confounding factors. Spearman correlation was utilized to analyse the correlations between ABI, Ba-PWV, and MoCA total scores and sub-scores in ALI patients.

RESULTS

Participants with cognitive impairment had significantly higher Ba-PWV and lower ABI than those with normal cognition. Correlation analysis suggested that Ba-PWV (r = -0.854, p < 0.05) and ABI (r = 0.734, p < 0.05) were correlated with MoCA total scores; of all MoCA sub-scores, visuospatial/executive function was the most strongly correlated with the vascular variables. In the binary logistic regression analysis, Ba-PWV (odds ratio [OR] = 4.507, 95% confidence interval [CI] = 2.152-9.441) and ABI (OR = 1.124, 95% CI = 1.015-1.254) were significantly associated with MCI, even after adjusting for lipoprotein (a) and systolic and diastolic blood pressure.

CONCLUSION

The present study suggested that a higher Ba-PWV and a lower ABI were independent risk factors for MCI in patients with ALI.

Cortical cerebral microinfarcts predict cognitive decline in memory clinic patients

Cortical cerebral microinfarcts (CMIs) - a novel MRI marker of cerebral vascular pathology have been linked with dementia and impaired cognition in cross-sectional studies. However, it is unknown if cortical CMIs are an indicator of further cognitive decline. We sought to examine whether baseline cortical CMIs predict cognitive decline in a prospective memory-clinic setting. A total of 313 patients with baseline 3T MRI scans and at least two neuropsychological assessments obtained a minimum of one year apart were recruited. Cortical CMIs were graded on baseline MRI according to a validated protocol. The Montreal Cognitive Assessment (MoCA) and a detailed neuropsychological battery were used to assess cognition. Patients with increased cortical CMIs showed greater decline in MoCA and global cognition per year. Patients with > 2 cortical CMIs decline on average by 2 scores on MoCA and 0.5 on global cognition at year two which corresponds to 109.8% and 184.5% greater decline when compared to those without CMIs. Furthermore, cortical CMIs at baseline were associated with accelerated decline in memory and language domains. Similar associations were observed when analysis was restricted to demented patients. Cortical CMIs together with other cerebrovascular disease markers can be used to design clinical trials in vascular cognitive impairment.

A Low Ankle-Brachial Index and High Brachial-Ankle Pulse Wave Velocity Are Associated with Poor Cognitive Function in Patients Undergoing Hemodialysis

Patients with end-stage renal disease (ESRD) have an increased risk of both impaired cognitive function and peripheral artery disease (PAD) than the general population. The association between PAD and dementia is recognized, but there are limited studies in patients with ESRD. The aim of this study was to evaluate the relationship between ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV) and cognitive impairment in patients receiving hemodialysis (HD). We enrolled 136 prevalent HD patients (mean age 59.3 ± 10.5 years, 55.9% male). Cognitive performance was measured using the Montreal Cognitive Assessment (MoCA) and Cognitive Abilities Screening Instrument (CASI) by trained psychiatrists. Associations between the cognitive function and ABI and baPWV were assessed using multiple linear regression analysis. Compared with HD patients with ABI ≥ 0.9, patients with ABI < 0.9 had lower MoCA score (p = 0.027) and lower CASI score but did not achieve significant level (p = 0.056). In the multivariate stepwise linear regression analysis, ABI (per 0.1) was independently positively associated with the MoCA score (β coefficient = 0.62, p = 0.011) and the CASI score (β coefficient = 1.43, p = 0.026). There is a negative association between baPWV (per 100 cm/s) and CASI (β coefficient = −0.70, p = 0.009). In conclusion, a low ABI or high baPWV was associated with a lower cognitive function in HD patients.

[The relationship of pathological ankle-brachial index and cognitive decline in patients after ischemic stroke]

AIM

To identify associations between cognitive impairment and values of ankle-brachial index (ABI) in patients after ischemic stroke at discharge from the hospital and over one-year follow-up.

MATERIAL AND METHODS

The study included 375 patients with normal (n=192) and elevated (n=153) ABI who underwent ischemic stroke (IS). Neurological examination was performed using NIHSS, the Rankin scale, Barthel index, Rivermead Mobility Index at discharge from the hospital and over one-year follow-up.

RESULTS AND CONCLUSION

Patients with elevated ABI had marked cognitive impairment and more severe neurological deficit compared to patients with normal ABI. Evaluation of ABI can help in predicting the development of post-stroke cognitive impairment in patients with IS.

Ankle brachial index and cognitive function among Hispanics/Latinos: Results from the Hispanic Community Health Study/Study of Latinos

BACKGROUND AND AIMS

The Ankle-Brachial index (ABI) is a well-accepted measure of peripheral artery disease (arterial stenosis and stiffness) and has been shown to be associated with cognitive function and disorders; however, these associations have not been examined in Hispanics/Latinos. Therefore, we sought to examine relationships between ABI and cognitive function among diverse middle-age and older Hispanics/Latinos.

METHODS

We used cross-sectional data on n = 7991 participants aged 45-74 years, without stroke or coronary heart disease, from the Hispanic Community Health Study/Study of Latinos. Our primary outcome, global cognition (GC), was a continuous composite score of four cognitive domains (verbal learning and memory, verbal fluency, executive function, and mental status). Secondary outcomes were the individual tests representing these domains. The ABI was analyzed continuously and categorically with standard clinical cut-points. We tested associations using generalized survey regression models incrementally adjusting for confounding factors. Age, sex, hypertension, diabetes, and dyslipidemia moderations were examined through interactions with the primary exposure.

RESULTS

In age, sex, and education adjusted models, continuous ABI had an inverse u-shape association with worse GC. We found similar associations with measures of verbal learning and memory, verbal fluency, executive function, but not with low mental status. The associations were attenuated, but not completely explained, by accounting for the confounders and not modified by age, sex, education, and vascular disease risks.

CONCLUSIONS

In addition to being a robust indicator of arterial compromise, our study suggests that abnormal ABI readings may also be useful for early signaling of subtle cognitive deficits.

Ankle brachial index, MRI markers and cognition: The Epidemiology of Dementia in Singapore study

BACKGROUND AND AIMS

Previous studies showed an independent association of low ankle-brachial index (ABI) with cognitive impairment. However, the association between low ABI and cognition in the presence of both cerebrovascular disease (CeVD) and neurodegeneration is lacking. We aimed at investigating a) the association of low ABI with markers of CeVD and cortical thickness, and b) whether the association of low ABI with cognition is influenced by these markers.

METHODS

Data was drawn from the Epidemiology of Dementia In Singapore (EDIS) study where all participants (n = 832) underwent neuropsychological tests and 3T brain magnetic resonance imaging (MRI) to assess CeVD markers as well as cortical thicknesses. Cognitive function was expressed as a global composite z-score and domain-specific z-scores of a comprehensive neuropsychological battery.

RESULTS

Multivariate analyses showed low ABI to be independently associated with intracranial stenosis [odds ratios (OR): 1.51; 95% confidence interval (CI):1.23-1.87] and lacunar infarcts [OR: 1.29; 95% CI: 1.06-1.57]. A low ABI was also independently associated with smaller cortical thickness globally [β: 0.09; 95% CI: 0.27-0.16] as well as with the limbic [β: 0.10; 95% CI: 0.03-0.17], temporal [β: 0.09; 95% CI: 0.02-0.15], parietal [β: 0.08; 95% CI: 0.02-0.15], and occipital [β: 0.09; 95% CI: 0.03-0.16] lobes. Low ABI was associated with worse performance in verbal memory [β: 0.06; 95% CI: 0.01-0.12], which became attenuated in the presence of MRI markers.

CONCLUSIONS

A low ABI is associated with MRI markers, and affects cognition in the presence of CeVD and neurodegeneration. Atherosclerosis should be targeted as a potentially modifiable risk factor to prevent cognitive disorders.

Arterial stiffness and cognitive impairment

BACKGROUND

Arterial stiffness is one of the earliest indicators of changes in vascular wall structure and function and may be assessed using various indicators, such as pulse-wave velocity (PWV), the cardio-ankle vascular index (CAVI), the ankle-brachial index (ABI), pulse pressure (PP), the augmentation index (AI), flow-mediated dilation (FMD), carotid intima media thickness (IMT) and arterial stiffness index-β. Arterial stiffness is generally considered an independent predictor of cardiovascular and cerebrovascular diseases. To date, a significant number of studies have focused on the relationship between arterial stiffness and cognitive impairment.

OBJECTIVES AND METHODS

To investigate the relationships between specific arterial stiffness parameters and cognitive impairment, elucidate the pathophysiological mechanisms underlying the relationship between arterial stiffness and cognitive impairment and determine how to interfere with arterial stiffness to prevent cognitive impairment, we searched PUBMED for studies regarding the relationship between arterial stiffness and cognitive impairment that were published from 2000 to 2017. We used the following key words in our search: "arterial stiffness and cognitive impairment" and "arterial stiffness and cognitive impairment mechanism". Studies involving human subjects older than 30years were included in the review, while irrelevant studies (i.e., studies involving subjects with comorbid kidney disease, diabetes and cardiac disease) were excluded from the review.

RESULTS

We determined that arterial stiffness severity was positively correlated with cognitive impairment. Of the markers used to assess arterial stiffness, a higher PWV, CAVI, AI, IMT and index-β and a lower ABI and FMD were related to cognitive impairment. However, the relationship between PP and cognitive impairment remained controversial. The potential mechanisms linking arterial stiffness and cognitive impairment may be associated with arterial pulsatility, as greater arterial pulsatility damages the cerebral microcirculation, which causes various phenomena associated with cerebral small vessel diseases (CSVDs), such as white matter hyperintensities (WMHs), cerebral microbleeds (CMBs), and lacunar infarctions (LIs). The mechanisms underlying the relationship between arterial stiffness and cognitive impairment may also be associated with reductions in white matter and gray matter integrity, medial temporal lobe atrophy and Aβ protein deposition. Engaging in more frequent physical exercise; increasing flavonoid and long-chain n-3 polyunsaturated fatty acid consumption; increasing tea, nitrite, dietary calcium and vitamin D intake; losing weight and taking medications intended to improve insulin sensitivity; quitting smoking; and using antihypertensive drugs and statins are early interventions and lifestyle changes that may be effective in preventing arterial stiffness and thus preventing cognitive impairment.

CONCLUSION

Arterial stiffness is a sensitive predictor of cognitive impairment, and arterial stiffness severity has the potential to serve as an indicator used to facilitate treatments designed to prevent or delay the onset and progression of dementia in elderly individuals. Early treatment of arterial stiffness is beneficial and recommended.

Association Between Subclinical Cardiac Biomarkers and Clinically Manifest Cardiac Diseases With Cortical Cerebral Microinfarcts

Importance

Subclinical and clinical cardiac diseases have been previously linked to magnetic resonance imaging (MRI) manifestations of cerebrovascular disease, such as lacunes and white matter hyperintensities, as well as dementia. Cortical cerebral microinfarcts (CMIs), a novel MRI marker of cerebral vascular disease, have not been studied, to date, in relation to subclinical and clinical cardiac diseases.

Objective

To examine the association of blood biomarkers of subclinical cardiac disease and clinically manifest cardiac diseases with CMIs graded on 3-T MRI in a memory clinic population.

Design, Setting, and Participants

This baseline cross-sectional analysis of a cohort study performed from August 12, 2010, to July 28, 2015, included 464 memory clinic participants. All participants underwent collection of blood samples, neuropsychological assessment, and 3-T MRI.

Exposures

N-terminal pro-brain natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) concentrations were measured by electrochemiluminescence immunoassays. Cardiac disease was defined as a history of atrial fibrillation, ischemic heart diseases, or congestive heart failure.

Main Outcomes and Measures

The CMIs were graded according to a previously validated protocol.

Results

Of 464 participants, 124 had insufficient blood plasma samples and 97 had no CMI grading (none, incomplete, or ungradable MRI), leaving a sample size of 243 for final analysis (mean [SD] age, 72.8 [9.1] years; 116 men [42.9%]). Seventy participants (28.8%) had cortical CMIs (median, 1; range, 0-43). Compared with participants with no CMIs, those with CMIs had a significantly higher prevalence of atrial fibrillation (rate ratio [RR], 1.62; 95% CI, 1.20-21.8), ischemic heart disease (RR, 4.31; 95% CI, 3.38-5.49), and congestive heart failure (RR, 2.05; 95% CI, 1.29-3.25). Significantly higher levels of NT-proBNP (RR, 3.16; 95% CI, 2.33-4.27) and hs-cTnT (RR, 2.17; 95% CI, 1.00-4.74) were found in participants with CMIs. In multivariate models adjusted for demographics and vascular risk factors, higher levels of NT-proBNP (RR, 3.19; 95% CI, 2.62-3.90) and hs-cTnT (RR, 4.86; 95% CI, 3.03-7.08) were associated with CMIs. These associations persisted even after excluding patients with clinically manifest cardiac disease.

Conclusions and Relevance

This study found that biomarkers of subclinical cardiac disease and clinically manifest cardiac diseases were associated with CMIs on 3-T MRI in patients attending a memory clinic, suggesting that cardiac disease may contribute to the development of CMIs. Hence, cardiac dysfunction should be targeted as a potentially modifiable factor to prevent CMI-related brain injury.

Subcortical Atrophy in Cognitive Impairment and Dementia

BACKGROUND

Cortical atrophy is a key neuroimaging feature of dementia. However, the role of subcortical gray matter reduction in cognitive impairment has not been explored extensively.

OBJECTIVES

We examined the risk factors of subcortical structures on neuroimaging and their association with cognitive impairment and dementia.

METHODS

Data from two studies were used: a subsample from the Epidemiology of Dementia in Singapore (EDIS) study of non-demented community-dwelling subjects (n = 550) and a case-control study. Subjects underwent similar neuropsychological tests and brain MRI. Subcortical volumes of accumbens, amygdala, caudate, pallidum, putamen, thalamus, hippocampus, and brainstem were measured. Cognitive impairment no dementia (CIND), dementia and its subtypes, vascular cognitive impairment (VCI), were defined using accepted criteria. Cognitive function was also expressed as both composite and domain-specific Z-scores.

RESULTS

In the EDIS study, age, female gender, Malay ethnicity, diabetes, lacunar-infarcts, and white matter lesions were the most important risk factors for subcortical atrophy. Moreover, smaller volumes of accumbens, amygdala, caudate, thalamus, and brainstem were significantly associated with lower cognitive composite Z-scores. With respect to clinical outcomes in the case-control study, structures such as the accumbens, caudate, putamen, and hippocampus were associated with both CIND and dementia. Smaller caudate and pallidum volumes were related to VCI whereas amygdalar atrophy was only associated with non-VCI. Furthermore, subcortical atrophy was related to both VCI and non-VCI.

CONCLUSION

Subcortical gray matter atrophy is not only observed in dementia, but also in the preclinical stages of cognitive impairment. Furthermore, besides VCI, subcortical structures were also related to non-VCI.

A combined measure of vascular risk for white matter lesions

BACKGROUND

Though hypertension is a commonly studied risk factor for white matter lesions (WMLs), measures of blood pressure may fluctuate depending on external conditions resulting in measurement error. Indicators of arterial stiffening and reduced elasticity may be more sensitive indicators of risk for WMLs in aging; however the interdependent nature of vascular indicators creates statistical complications.

OBJECTIVE

The purpose of the study was to determine whether a factor score comprised of multiple vascular indicators would be a stronger predictor of WMLs than traditional measures of blood pressure.

METHODS

In a sample of well-characterized nondemented older adults, we used a factor analytic approach to account for variance common across multiple vascular measures while reducing measurement error. The result was a single factor score reflecting arterial stiffness and reduced elasticity. We used this factor score to predict white matter lesion volumes acquired via fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging.

RESULTS

The combined vascular factor score was a stronger predictor of deep WML (β = 0.42, p < 0.001) and periventricular WML volumes (β = 0.49, p < 0.001). After accounting for the vascular factor, systolic and diastolic blood pressure measurements were not significant predictors.

CONCLUSIONS

This suggests that a combined measure of arterial elasticity and stiffening may be a stronger predictor of WMLs than systolic and diastolic blood pressure accounting for the multicollinearity associated with a variety of interrelated vascular measures.

Prevalence of Brain Microbleeds in Alzheimer Disease: A Systematic Review and Meta-Analysis on the Influence of Neuroimaging Techniques

BACKGROUND AND PURPOSE

The literature on the prevalence of Alzheimer disease-associated cerebral microbleeds assessed with MR imaging shows considerable heterogeneity in terms of imaging techniques and parameters. Our aim was to perform a meta-analysis of the role of imaging techniques, including image acquisition, field strength and scanner type, and clinical and demographic factors on the reported prevalence of microbleeds in Alzheimer disease.

MATERIALS AND METHODS

The prevalence of microbleeds was examined with respect to a priori-selected moderating variables via meta-analytic tools of literature reports.

RESULTS

Fourteen unique studies providing 15 microbleed prevalence rates met the selection criteria for inclusion. The aggregate prevalence of microbleeds was 24% (95% CI, 19%-28%). Scan (SWI = 40%, gradient echo = 18%, EPI = 19%) and field strength (slope = 0.39; standard error = 15, P < .01) influenced the prevalence of microbleeds. The associations between microbleeds and age, sex, and global cognitive status were not significant. After updating the literature, the aggregate prevalence remained in the 95% CI range.

CONCLUSIONS

Imaging technique and field strength are strongly associated with the prevalence of microbleeds over the global aggregate. Standardized imaging protocols for identification of microbleeds are recommended to minimize confounds.

Ankle-brachial index and inter-artery blood pressure differences as predictors of cognitive function in overweight and obese older adults with diabetes: results from the Action for Health in Diabetes movement and memory study

OBJECTIVE

Ankle-brachial index (ABI) and interartery systolic blood pressure differences, as markers of vascular disease, are plausible risk factors for deficits in cognitive function among overweight and obese adults with type 2 diabetes.

METHODS

The ABI and maximum interartery differences (MIAD) in systolic blood pressures were assessed annually for five years among 479 participants assigned to the control condition in a randomized clinical trial of a behavioral weight loss intervention. A battery of standardized cognitive function tests was administered 4 to 5 years later. Analyses of covariance were used to assess relationships that ABI, MIAD, and progression of ABI and MIAD had with cognitive function.

RESULTS

There was a curvilinear relationship between ABI and a composite index of cognitive function (p = 0.03), with lower ABI being associated with poorer function. In graded fashions, both greater MIAD and increases in MIAD over time also had modest relationships with poorer verbal memory (both p ≤ 0.05), processing speed (both p ≤ 0.05), and composite cognitive function (both p < 0.04). These relationships were independent of each other and remained evident after extensive covariate adjustment.

CONCLUSIONS

In overweight and obese adults with type 2 diabetes, lower ABI and larger interartery systolic blood pressure differences have modest, independent, graded relationships with poorer cognitive function 4-5 years later.

Risk Factors and Consequences of Cortical Thickness in an Asian Population

Cortical thickness has been suggested to be one of the most important markers of cortical atrophy. In this study, we examined potential risk factors of cortical thickness and its association with cognition in an elderly Asian population from Singapore. This is a cross-sectional study among 572 Chinese and Malay patients from the ongoing Epidemiology of Dementia in Singapore (EDIS) Study, who underwent comprehensive examinations including neuropsychological testing and brain magnetic resonance imaging (MRI). Cortical thickness (in micrometers) was measured using a model-based automated procedure. Cognitive function was expressed as composite and domain-specific Z-scores. Cognitive impairment was categorized into cognitive impairment no dementia (CIND)-mild, CIND-moderate, and dementia in accordance with accepted criteria. Linear regression models were used to examine the association between various risk factors and cortical thickness. With respect to cognition as outcome, both linear (for Z-scores) and logistic (for CIND/dementia) regression models were constructed. Initial adjustments were made for age, sex, and education, and subsequently for other cardiovascular risk factors and MRI markers. Out of 572 included patients, 171 (29.9%) were diagnosed with CIND-mild, 197 (34.4%) with CIND-moderate, and 28 (4.9%) with dementia. Risk factors related to a smaller cortical thickness were increased age, male sex, Malay ethnicity, higher blood glucose, and body mass index levels and presence of lacunar infarcts on MRI. Smaller cortical thickness was associated with CIND moderate/dementia [odds ratio (OR) per standard deviation (SD) decrease: 1.70; 95% confidence interval (CI): 1.19-2.44, P = 0.004] and with composite Z-score reflecting global cognitive functioning [mean difference per SD decrease: -0.094; 95% CI: -0.159; -0.030, P = 0.004]. In particular, smaller cortical thicknesses in the occipital and temporal lobes were related to cognitive impairment. Finally, in terms of specific cognitive domains, the most significant associations were found for executive function, visuoconstruction, and visual memory. Smaller cortical thickness is significantly associated with cognitive impairment, suggesting a contribution of diffuse cortical atrophy beyond the medial temporal lobe to cognitive function. These findings suggest that cortical thinning is a biomarker of neurodegenerative changes in the brain not only in dementia, but also in its preclinical stages.

Associations Between Ankle-Brachial Index and Cognitive Function: Results From the Lifestyle Interventions and Independence for Elders Trial

OBJECTIVE

The objective of this study was to evaluate cross-sectional and longitudinal associations between ankle-brachial index (ABI) and indicators of cognitive function.

DESIGN

Randomized clinical trial (Lifestyle Interventions and Independence for Elders Trial).

SETTING

Eight US academic centers.

PARTICIPANTS

A total of 1601 adults ages 70-89 years, sedentary, without dementia, and with functional limitations.

MEASUREMENTS

Baseline ABI and interviewer- and computer-administered cognitive function assessments were obtained. These assessments were used to compare a physical activity intervention with a health education control. Cognitive function was reassessed 24 months later (interviewer-administered) and 18 or 30 months later (computer-administered) and central adjudication was used to classify individuals as having mild cognitive impairment, probable dementia, or neither.

RESULTS

Lower ABI had a modest independent association with poorer cognitive functioning at baseline (partial r = 0.09; P < .001). Although lower baseline ABI was not associated with overall changes in cognitive function test scores, it was associated with higher odds for 2-year progression to a composite of either mild cognitive impairment or probable dementia (odds ratio 2.60 per unit lower ABI; 95% confidence interval 1.06-6.37). Across 2 years, changes in ABI were not associated with changes in cognitive function.

CONCLUSION

In an older cohort sedentary individuals with dementia and with functional limitations, lower baseline ABI was independently correlated with cognitive function and associated with greater 2-year risk for progression to mild cognitive impairment or probable dementia.