Carotid intima-media thickness and cognitive decline: what does it mean for prevention of dementia?

Risk of dementia in the elderly with non-alcoholic fatty liver disease: A nested case-control study in the Republic of Korea

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) is known to be associated with metabolic syndrome of which diabetes is an important component. Although diabetes is a known risk factor for dementia, studies on the association between NAFLD and dementia still produce conflicting results. This study aimed to determine whether NAFLD would be a risk factor for the development of dementia in an elderly population.

METHOD

This study included 107,369 subjects aged ≥60 years in the Korean National Health Insurance Service-Senior cohort, entered in 2009 and followed up until 2015. NAFLD was diagnosed by calculating fatty liver index (FLI). Subjects were screened for dementia at baseline using a Korean Dementia Screening Questionnaire, and dementia was diagnosed using ICD-10 codes. Controls were randomly selected at a ratio of 1:5 from individuals who were at risk of becoming the case subjects at the time of selection.

RESULTS

From 107,369 subjects, 65,690 stroke- and dementia-free subjects without chronic hepatitis B or C or excessive alcohol drinking were selected for evaluation. Having NAFLD, determined by FLI, was associated with increased risk of dementia development (adjusted odds ratio [AOR] 1.493; 95% confidence interval [CI] 1.214-1.836). The increased risk of dementia in NAFLD subjects was independent of type 2 diabetes (AOR 1.421; 95% CI 1.013-1.994, in subjects with diabetes: AOR 1.540; 95% CI 1.179- 2.010, in subjects without diabetes).

CONCLUSION

In this population-based nested case-control study, having NAFLD increased the risk of dementia in elderly individuals, independent of accompanying diabetes.

Non-alcoholic fatty liver disease and cognitive function in middle-aged adults: the CARDIA study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is associated with cardiovascular disease (CVD) risk factors that have been linked to cognitive decline. Whether NAFLD is associated with cognitive performance in midlife remains uncertain.

METHODS

Coronary Artery Risk Development in Young Adults study participants with CT examination and cognitive assessment at Y25 (2010-2011; n = 2809) were included. Cognitive function was reassessed at Y30. NAFLD was defined according to liver attenuation and treated both continuously and categorically (using ≤ 40 and ≤ 51 Hounsfield units to define severity) after exclusion for other causes of liver fat. Cognitive tests including the Digit Symbol Substitution (processing speed), Rey Auditory Verbal Learning (verbal memory), and Stroop (executive function) were analyzed with standardized z-scores. Linear models were constructed to (a) examine the cross-sectional associations of NAFLD with cognitive scores and (b) evaluate its predictive role in 5-year change in cognitive performance.

RESULTS

Participants' mean age (Y25) was 50.1 (SD 3.6) years (57% female; 48% black), with 392 (14%) having mild NAFLD and 281 (10%) having severe NAFLD. NAFLD was positively associated with CVD risk factors and inversely associated with cognitive scores. However, after adjustment for CVD risk factors, no associations were shown between NAFLD and cognitive scores (all βs ≈ 0). Similarly, no associations were observed with 5-year cognitive decline. CVD history, hypertension, smoking, diabetes and hypertriglyceridemia showed stronger associations with baseline cognitive scores and were predictive of subsequent cognitive decline (all P ≤ .05).

CONCLUSION

Among middle-aged adults, inverse associations between NAFLD and cognitive scores were attenuated after adjustment for CVD risk factors, with the latter predictive of poorer cognitive performance both at baseline and follow-up.

Significance of increased CIMT with coexisting carotid plaques in cerebral white matter lesions in elders

It is very common that increased carotid intima media thickness (CIMT) and carotid plaque coexist in a single subject in elderly patients with white matter lesions (WMLs). In this study we investigated whether the coexistence of increased CIMT and carotid plaque is more strongly associated with the presence and extent of WMLs than either alone. All patients were classified into 1 of the following 4 groups: without either increased CIMT (I) or carotid plaque (P): I(-)P(-); with only increased CIMT: I(+)P(-); with only carotid plaque: I(-)P(+); and with both increased CIMT and carotid plaque: I(+)P(+). The presence and severity of periventricular WMLs (PWMLs) and deep WMLs (DWMLs) were assessed and the prevalence of MRI findings by the Cochran-Armitage trend test was calculated. The characteristics of subjects showed that the percentages of patients with increased CIMT and carotid plaque in the DWMLs group and the PWMLs group were significantly higher than those without WMLs group. Both DWMLs and PWMLs were strongly associated with age, carotid plaque and CIMT. Furthermore, the Cochran-Armitage trend test indicated that the prevalence of MRI findings of PWMLs and DWMLs increased in the order of I(-)P(-)< I(+)P(-)< I(-)P(+)< I(+)P(+) (P<0.0001). For the patients with DWMLs, the grades of both I(+)P(-) and I(+)P(+) were increased significantly compared to I(-)P(-) (P<0.0025, P<0.05, respectively) without such a difference found in patients with PWMLs. Our results suggested that the coexistence of increased CIMT and carotid plaque is most closely associated with WMLs, and that increased CIMT is associated with the severity of DWMLs, whereas carotid plaque is related to the presence of WMLs.

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.

Is dementia preventable? Focus on Alzheimer's disease

The prevention of dementia, and particularly of Alzheimer's disease, is a major challenge for researchers and clinicians. In this article, the mixture of evidence, observations and hypotheses in the current literature is categorized into four avenues for possible preventive interventions, as suggested by the NIH State-of-the-Science Conference. The main categories are: antihypertensive medications; nutrition; cognitive engagement; and physical activity. There is, as yet, no conclusive evidence, but each category may hold promise for the prevention of dementia. The robust findings are as follows: cognitive engagement and regular physical activity may reduce the risk of Alzheimer's disease; the Mediterranean diet and consumption of omega-3 fatty acids deserves further elucidation; and the meticulous management of risk factors, and especially hypertension, is the infrastructure of Alzheimer's disease prevention.

Subclinical atherosclerosis is related to lower neuronal viability in middle-aged adults: a 1H MRS study

BACKGROUND

Increased carotid artery intima-media thickness (IMT) is a noninvasive marker of systemic arterial disease, associated with atherosclerosis, abnormal arterial mechanics, myocardial infarction, and stroke. In the elderly, clinically elevated IMT is related to diminished attention-executive function. In this context, previous work involving paper-and-pencil measures of cognition has demonstrated that a threshold of pathology (i.e., IMT>or=0.9 mm) is needed before IMT consistently relates to poor neuropsychological test performance. Given the critical role of arterial health in the development of cognitive dysfunction, the goal of this study was to investigate early markers of brain vulnerability by examining subclinical levels of IMT in relation to a sensitive marker of neuronal integrity, cerebral N-acetyl-aspartate/creatine (NAA/Cr) ratio, in midlife.

METHODS

A total of 40 participants aged 50+/-6 years, underwent neuropsychological assessment, proton magnetic resonance spectroscopy ((1)H MRS) examination of occipitoparietal grey matter and B-mode ultrasound of the common carotid artery. IMT was defined as the distance between the luminal-endothelial interface and the junction between the media and the adventitia. The relation between IMT and cerebral metabolite ratios was modeled using a single multivariate multiple regression analysis adjusted for age and current systolic blood pressure.

RESULTS

Increased IMT was associated with significantly lower NAA/Cr ratios (IMT beta=-0.62, p=0.001), independent of age and systolic blood pressure (F(3,36)=4.928, p=0.006).

CONCLUSIONS

Our study extends previous findings by demonstrating a significant relationship between IMT and NAA concentration, suggesting compromised neuronal viability even at IMT levels below thresholds for clinical end-organ damage.

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

OBJECTIVE

Several vascular risk factors have been linked to cognitive decline. However, little is known about the association between the atherosclerotic process and cognitive impairment. We investigated whether carotid intima-media thickness (IMT) predicts the risk of cognitive impairment and whether the putative impairment is specific for some cognitive domains.

METHODS

A 12-year population-based follow-up study was performed for a total of 91 women, aged 60-70 years at baseline. Ultrasonographically assessed carotid artery IMT and the Mini-Mental State Examination test were performed at baseline and 12-year follow-up. A detailed cognitive evaluation for memory and cognitive speed was performed in 2003. The mean of left and right carotid bifurcation IMT was used in the analyses for association with the risk for poor cognitive speed and memory.

RESULTS

Increased IMT at baseline was an independent predictor for poor memory (beta = -5.004, 95% confidence interval = -7.74 to -2.27; p = 0.001) and cognitive speed (beta = 2.562, 95% confidence interval = 1.19-4.94; p = 0.035) at 12-year follow-up after adjustment for age, education, depression, plasma LDL cholesterol, systolic blood pressure, cardiovascular disease, hormone replacement therapy, smoking, alcohol consumption and physical activity. The risk for poor memory (p = 0.023 for linear trend) and cognitive speed (p = 0.070 for linear trend) increased with increasing IMT tertiles.

CONCLUSIONS

Carotid IMT predicts an increased risk for cognitive impairment, particularly poor memory and cognitive speed, in elderly women.

Atherosclerosis and risk for dementia

OBJECTIVE

Atherosclerosis has been implicated in the development of dementia and its major subtypes, Alzheimer's disease and vascular dementia. However, support for this association mainly comes from cross-sectional studies. We investigated the association of atherosclerosis with dementia and subtypes of dementia during long follow-up, with various noninvasive measures of atherosclerosis.

METHODS

This study was based on 6,647 participants in the Rotterdam Study, a population-based prospective cohort study among 7,983 elderly subjects. At baseline (1990-1993) and at the third survey (1997-1999), common carotid intima media thickness, carotid plaques, and peripheral arterial disease (measured as ankle-brachial index) were measured. During follow-up (mean, 9.0 years), 678 subjects developed dementia. We estimated the associations of different measures of atherosclerosis with risk for dementia and subtypes of dementia by means of Cox proportional hazard models. Analyses were repeated and stratified on duration of follow-up. To evaluate competing risk for mortality, we examined the association between measures of atherosclerosis and risk for dementia or mortality by combining the two in a single outcome measure.

RESULTS

We found that atherosclerosis, predominantly carotid atherosclerosis, was associated with an increased risk for dementia during short follow-up. This association attenuated with longer follow-up, likely because of the strong association between atherosclerosis and mortality. The associations did not differ across apolipoprotein E genotypes.

INTERPRETATION

Our findings suggest that atherosclerosis is associated with an increased risk for dementia. Stronger associations between atherosclerosis and mortality may attenuate the association between atherosclerosis and dementia in prospective cohort studies with long follow-up periods.

Common Carotid Artery Intima-Media Thickness, Carotid Plaques, and Walking Speed

Background and Purpose— Gait dysfunction is an important cause of disability among the elderly and may be, in part, of vascular origin. We studied the association between carotid ultrasound parameters and measures of gait and balance in subjects 65 to 85 years of age who participated in the baseline phase of the Three-City Study in the Dijon center.

Methods— The study population comprised 2572 noninstitutionalized individuals. Carotid plaques and common carotid artery intima-media thickness (CCA-IMT) were measured using ultrasonography. Gait and balance measures included walking speed and a modified version of the Tinetti scale.

Results— Mean maximum walking speed (MWS) decreased with increasing CCA-IMT and number of plaques ( P <10 −4 ). Compared with subjects in the lowest CCA-IMT quintile, the odds ratio (95% CI) for being in the lowest MWS quartile was 1.1 (0.8 to 1.6) in the second, 1.3 (0.9 to 1.8) in the third, 1.7 (1.2 to 2.4) in the fourth, and 2.2 (1.6 to 3.1) in the higher CCA-IMT quintile ( P <10 −4 ). Mean (SD) CCA-IMT was 0.716 (0.118) mm in subjects with a modified Tinetti score <16 (25th percentile) and 0.685 (0.109) mm in subjects with a score of ≥16 ( P =0.006). The proportion of subjects in the lowest MWS quartile ( P =0.006) or with a modified Tinetti score <16 ( P =0.05) increased with the number of plaques. These relations were attenuated after adjustment for vascular risk factors.

Conclusions— Carotid plaques and higher CCA-IMT values are associated with worse performances on gait and balance tests. Our results suggest that vascular factors may play an important and under-recognized role in motor function.