Metabolic syndrome and cognitive decline in elderly Latinos: findings from the Sacramento Area Latino Study of Aging study

Association Between Late-Life Blood Pressure and the Incidence of Cognitive Impairment: A Community-Based Prospective Cohort Study

OBJECTIVES

To investigate the association between late-life blood pressure and the incidence of cognitive impairment in older adults.

DESIGN

Prospective cohort study.

SETTING

Community-living older adults from 22 provinces in China.

PARTICIPANTS

We included 12,281 cognitively normal [Mini-Mental State Examination (MMSE) ≥ 24] older adults (median age: 81 years) from the Chinese Longitudinal Healthy Longevity Survey. Eligible participants must have baseline blood pressure data and have 1 or more follow-up cognitive assessments.

MEASUREMENTS

Baseline systolic (SBP) and diastolic blood pressure (DBP) were measured by trained internists. Cognitive function was evaluated by MMSE. We considered mild/moderate/severe cognitive impairment (MMSE <24, and MMSE decline ≥3) as the primary outcome.

RESULTS

The participants with hypertension had a significantly higher risk of mild/moderate/severe cognitive impairment (hazard ratio [HR] 1.17, 95% confidence interval [CI] 1.10-1.24). Overall, the associations with cognitive impairment seem to be hockey stick-shaped for SBP and linear for DBP, though the estimated effects for low SBP/DBP were less precise. High SBP was associated with a gradual increase in the risk of mild/moderate/severe cognitive impairment (P trend < .001). Compared with SBP 120 to 129 mmHg, the adjusted HR was 1.17 (95% CI 1.07-1.29) for SBP 130 to 139 mmHg, increased to 1.54 (95% CI 1.35-1.75) for SBP ≥180 mmHg. Analyses for high DBP showed the same increasing pattern, with an adjusted HR of 1.09 (95% CI 1.01-1.18) for DBP 90 to 99 mmHg and 1.19 (95% CI 1.02-1.38) for DBP ≥110 mmHg, as compared with DBP 70 to 79 mmHg.

CONCLUSION

Late-life high blood pressure was independently associated with cognitive impairment in cognitively normal Chinese older adults. Prevention and management of high blood pressure may have substantial benefits for cognition among older adults in view of the high prevalence of hypertension in this rapidly growing population.

Metabolic Syndrome and Neurocognition Among Diverse Middle-Aged and Older Hispanics/Latinos: HCHS/SOL Results

OBJECTIVE

Hispanics/Latinos have the highest risks for metabolic syndrome (MetS) in the U.S. and are also at increased risk for Alzheimer disease. In this study, we examined associations among neurocognitive function, MetS, and inflammation among diverse middle-aged and older Hispanics/Latinos.

RESEARCH DESIGN AND METHODS

Cross-sectional data (2008-2011) from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) were analyzed to examine associations between neurocognition and MetS among diverse Hispanics/Latinos (N = 9,136; aged 45-74 years).

RESULTS

MetS status was associated with lower global neurocognition, mental status, verbal learning and memory, verbal fluency, and executive function. Age significantly modified the associations between MetS and learning and memory measures. Significant associations between MetS and neurocognition were observed among middle-aged Hispanics/Latinos, and all associations remained robust to additional covariates adjustment.

CONCLUSIONS

We found that MetS was associated with lower neurocognitive function, particularly in midlife. Our findings support and extend current hypotheses that midlife may be a particularly vulnerable developmental period for unhealthy neurocognitive aging.

The role of metabolic syndrome factors on cognition using latent variable modeling: The neurocognitive study on aging

OBJECTIVE

Although metabolic syndrome (MetS) has been shown to increase the risk of cognitive decline, it still remains unclear whether the risk is related to MetS as a whole or its individual factors. The aim of the present study was to explore whether MetS or its individual factors are associated with a lower cognitive function in older adults in a Mediterranean population using latent variable modeling.

METHOD

Neurocognitive data from 640 Greek-Cypriot community dwellers (female 59.1%), aged ≥55 years, in good general health, were analyzed. Assessments of anthropometric, blood pressure, fasting blood glucose, total cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, and triglyceride concentrations were carried out to investigate the relationship between MetS factors and cognitive-linguistic outcomes of language, executive function, and verbal episodic memory.

RESULTS

When the MetS factors were modeled as a single latent variable, they had small negative effects on language and executive functions. Significance was not retained after age and education were controlled for. When individual MetS factors along with age and education were modeled as predictors, there were moderate negative age effects, whereas education yielded strong positive effects on all three cognitive outcomes. Weak significant negative coefficients of body mass index (BMI) and blood glucose were found for executive functions, and a weak significant positive effect of BMI was found for memory. Separate analysis by sex resulted in minor but significant differences.

CONCLUSION

BMI and blood glucose predicted cognitive performance after controlling for age and education, and thus their proper management should be taken into account for maintaining cognitive health in aging. Findings also demonstrate the importance of education and age in studies investigating cardiometabolic risk factors and cognitive function, as well as the need for further research on the effects of sex.

Helping Hispanic Dementia Caregivers Cope with Stress Using Technology-based Resources

OBJECTIVES

The objectives of this study were to develop and evaluate a culturally appropriate intervention for Hispanic/Latino caregivers of individuals with dementia, using a structured online program without professional involvement to improve well-being, decrease stress, and reduce depression.

METHODS

The Webnovela Mirela, an online Spanish-language telenovela, was designed specifically to teach caregivers how to cope with dementia caregiving. A prototype of Webnovela Mirela was tested in a pilot study with 25 Hispanic/Latino dementia caregivers, 19 of whom completed the study.

RESULTS

Data were analyzed using paired-samples t-tests. Results indicated a significant decrease from pre- to post-treatment in levels of stress and symptoms of depression (p = .045).

CONCLUSIONS

The pilot study indicated high potential of the Webnovela Mirela to help the target population and demonstrated that the telenovela format is acceptable and helpful for Hispanic dementia caregivers.

CLINICAL IMPLICATIONS

Study outcomes suggested that self-paced approaches with culturally relevant content in an appealing format for the target population have the potential to implement effective interventions. Furthermore, technology enables support programs to reach a broader audience in a cost-effective manner. Of note is the fact that minimal professional and/or personal assistance was required for caregivers to complete this intervention.

Blood Pressure and Hispanic/Latino Cognitive Function: Hispanic Community Health Study/Study of Latinos Results

BACKGROUND

Hispanics/Latinos are at increased risk for cardiovascular disease and cognitive decline and dementias. High blood pressure (BP) has been implicated in both stroke and dementias. Associations between BP and cognition among diverse Latinos are still unpublished.

OBJECTIVE

We examined associations between cognition and four BP based measures among diverse Hispanics/Latinos. We hypothesized that higher BP, particularly systolic pressure, and increased arterial stiffness (i.e., pulse pressure), would be associated with lower cognitive function.

METHODS

We used baseline (2008-2011) Hispanic Community Health Study/Study of Latinos (HCHS/SOL; n = 9,019; ages 45-74 years) data to examine cognition in relation to BP measures.

RESULTS

In age, sex, and education adjusted models, systolic, pulse, and mean arterial pressure were consistently negatively associated with executive function, psychomotor speed and sustained attention, verbal episodic learning and memory, speech fluency, and mental status measures. These associations were attenuated but remained statistically significant in fully adjusted models.

CONCLUSION

Among middle-aged and older diverse Hispanics/Latinos, we found modest but consistent associations between indicators of arterial stiffness, and compromised blood flow and lower cognitive function. Clinical management and public health interventions to raise awareness and enhance BP management beginning in midlife could reduce disparities and improve population health by reducing cognitive decline burdens.

Metabolic Syndrome and cognitive decline in the elderly: A systematic review

Background

Metabolic Syndrome (MetS) refers to a cluster of metabolic disturbances which is associated with increased risk for vascular and degenerative conditions in general population. Although the relationship between vascular risk factors and dementia is undisputable, additional hazard for cognitive decline in older population with concurrent metabolic disorders still waits to be demonstrated. The present review aims to analyze data on MetS and risk for cognitive decline in elderly persons.

Methods

Database searches were performed in Medline, ISI and PsycINFO for articles assessing cognitive performances of older subjects with MetS.

Results

Of a total of 505 studies, 25 were selected for the review. Risk of selection biases was identified in all the studies. Although all articles followed recognized diagnostic recommendations for MetS, minor criteria modifications were detected in most of them. Hyperglycemia was consistently associated with impaired cognitive performances in older individuals, but the role of MetS for cognitive decline and for the onset of dementia showed heterogeneous results.

Discussion

Current available data in the literature concerning the impact of MetS on the cognition of older population is inconclusive and based on inconsistent evidence. Differential effects of individual MetS components and factors associated with the age of the sample may have accounted for divergent findings among articles, but larger and higher quality studies in this field are still needed.

Associations of dyslipidaemia and lipid-lowering treatment with risk of postoperative cognitive dysfunction: a systematic review and meta-analysis

BACKGROUND

Lipid imbalance is linked to age-related cognitive impairment, but its role in postoperative cognitive dysfunction (POCD) is unknown. Here, we present a systematic review and meta-analysis on dyslipidaemia, lipid-lowering treatment and POCD risk.

METHODS

PubMed, Ovid SP and Cochrane databases were searched for longitudinal studies that reported on associations of any measure of dyslipidaemia and/or lipid-lowering treatment with POCD as relative risks (RRs) or ORs. Fixed-effects inverse variance models were used to combine effects.

RESULTS

Of 205 articles identified in the search, 17 studies on 2725 patients (grand mean age 67 years; mean age range 61-71 years) with follow-up periods of 1 day to 4 years (median 7 days; IQR 1-68 days) were included. Studies focused almost exclusively on hypercholesterolaemia as a measure of dyslipidaemia and on statins as lipid-lowering treatment. Across 12 studies on hypercholesterolaemia, we found no association with POCD risk (RR 0.93; 95% CI 0.80 to 1.08; P=0.34). Statin use before surgery was associated with a reduced POCD risk across eight studies (RR 0.81; 95% CI 0.67 to 0.98; P=0.03), but data on treatment duration were lacking.

CONCLUSION

Statin users appear to be at reduced risk of POCD although hypercholesterolaemia per se may not be associated with POCD risk. Trial studies are needed to evaluate the usefulness of statins in POCD prevention.

Education, bilingualism, and cognitive trajectories: Sacramento Area Latino Aging Study (SALSA)

OBJECTIVE

This study examined the influence of education, country where education occurred, and monolingual-bilingual (English/Spanish) language usage on late life cognitive trajectories in the Sacramento Area Latino Study on Aging (SALSA), an epidemiological study of health and cognition in Hispanics, mostly of Mexican origin, age 60 and over (N = 1,499).

METHOD

SALSA followed a large cohort of older Latinos for up to 7 assessment waves from 1998 to 2007. Global cognition was assessed by using the Modified Mini Mental State Examination, and the Spanish English Verbal Learning Test was used to measure episodic memory. Education, country of origin, and language usage patterns were collected at the baseline assessment and used as predictors of longitudinal trajectories of cognition. Parallel process mixed effects models were used to examine effects of education and language variables on baseline cognition and rate of cognitive decline.

RESULTS

Mixed effects longitudinal models showed that education had strong effects on baseline global cognition and verbal memory but was not related to decline over up to 9 years of longitudinal follow-up. Differences in education effects between subgroups educated in Mexico and in the United States were minor. Monolingual-bilingual language usage was not related to cognitive decline, and bilinguals did not significantly differ from monolingual English speakers on baseline cognitive scores.

CONCLUSIONS

Hypotheses that higher education and bilingualism protect against late life cognitive decline were not supported and education effects on late-life cognitive trajectories did not substantially differ across U.S.- and Mexico-educated groups. (PsycINFO Database Record

The Association Between Weight Status, Weight History, Physical Activity, and Cognitive Task Performance

PURPOSE

Physical activity has been shown to attenuate the association between overweight/obesity and deleterious cardiovascular health-related outcomes, with emerging work also taking the duration of overweight/obesity into consideration. No previous work, however, has explored the interrelationships between physical activity, obesity, and obesity duration in the context of cognitive task performance, which was the purpose of this study.

METHOD

Data from the 1999-2002 National Health and Nutrition Examination Survey were used (N = 2322 adults 60-85 yrs). Physical activity was assessed via self-report, with body mass index (BMI) directly measured. Participants were classified into one of eight mutually exclusive groups: (0) normal weight now and 10 years ago and active now (n = 195), (1) normal weight and 10 years ago and inactive now (n = 265), (2) normal weight now but not 10 years ago and active now (n = 46), (3) normal weight now but not 10 years ago and inactive now (n = 123), (4) overweight/obese now but not 10 years ago and active now (n = 117), (5) overweight/obese now but not 10 years ago and inactive now (n = 168), (6) overweight/obese now and 10 years ago and active now (n = 435), and (7) overweight/obese now and 10 years ago and inactive now (n = 973). The digit symbol substitution test (DSST) was employed to assess cognitive task performance.

RESULTS

After adjustments, only individuals who were inactive (groups 1, 3, 5, and 7) had significantly lower cognitive task performance.

CONCLUSION

Being inactive, regardless of weight classification and duration of overweight/obesity, was inversely associated with cognitive task performance in this national sample of older adults.

Glycemia but not the Metabolic Syndrome is Associated with Cognitive Decline: Findings from the European Male Ageing Study

OBJECTIVE

Previous research has indicated that components of the metabolic syndrome (MetS), such as hyperglycemia and hypertension, are negatively associated with cognition. However, evidence that MetS itself is related to cognitive performance has been inconsistent. This longitudinal study investigates whether MetS or its components affect cognitive decline in aging men and whether any interaction with inflammation exists.

METHODS

Over a mean of 4.4 years (SD ± 0.3), men aged 40-79 years from the multicenter European Male Ageing Study were recruited. Cognitive functioning was assessed using the Rey-Osterrieth Complex Figure (ROCF), the Camden Topographical Recognition Memory (CTRM) task, and the Digit Symbol Substitution Test (DSST). High-sensitivity C-reactive protein (hs-CRP) levels were measured using a chemiluminescent immunometric assay.

RESULTS

Overall, 1,913 participants contributed data to the ROCF analyses and 1,965 subjects contributed to the CTRM and DSST analyses. In multiple regression models the presence of baseline MetS was not associated with cognitive decline over time (p > 0.05). However, logistic ordinal regressions indicated that high glucose levels were related to a greater risk of decline on the ROCF Copy (β = -0.42, p < 0.05) and the DSST (β = -0.39, p < 0.001). There was neither a main effect of hs-CRP levels nor an interaction effect of hs-CRP and MetS at baseline on cognitive decline.

CONCLUSION

No evidence was found for a relationship between MetS or inflammation and cognitive decline in this sample of aging men. However, glycemia was negatively associated with visuoconstructional abilities and processing speed.

Nutrition for the ageing brain: Towards evidence for an optimal diet

As people age they become increasingly susceptible to chronic and extremely debilitating brain diseases. The precise cause of the neuronal degeneration underlying these disorders, and indeed normal brain ageing remains however elusive. Considering the limits of existing preventive methods, there is a desire to develop effective and safe strategies. Growing preclinical and clinical research in healthy individuals or at the early stage of cognitive decline has demonstrated the beneficial impact of nutrition on cognitive functions. The present review is the most recent in a series produced by the Nutrition and Mental Performance Task Force under the auspice of the International Life Sciences Institute Europe (ILSI Europe). The latest scientific advances specific to how dietary nutrients and non-nutrient may affect cognitive ageing are presented. Furthermore, several key points related to mechanisms contributing to brain ageing, pathological conditions affecting brain function, and brain biomarkers are also discussed. Overall, findings are inconsistent and fragmented and more research is warranted to determine the underlying mechanisms and to establish dose-response relationships for optimal brain maintenance in different population subgroups. Such approaches are likely to provide the necessary evidence to develop research portfolios that will inform about new dietary recommendations on how to prevent cognitive decline.

Metabolic Syndrome as a Risk Factor for Alzheimer's Disease: Is Aβ a Crucial Factor in Both Pathologies?

SIGNIFICANCE

Recently, chronic degenerative diseases have become one of the main health problems worldwide. That is the case of Alzheimer's disease (AD) and metabolic syndrome (MetS), whose expression can be influenced by different risk factors. Recent Advances: In recent decades, it has been widely described that MetS increases the risk of cognitive impairment and dementia. MetS pathogenesis involves several vascular risk factors such as diabetes, dyslipidemia, hypertension, and insulin resistance (I/R).

CRITICAL ISSUES

Reported evidence shows that vascular risk factors are associated with AD, particularly in the development of protein aggregation, inflammation, oxidative stress, neuronal dysfunction, and disturbances in signaling pathways, with insulin receptor signaling being a common alteration between MetS and AD.

FUTURE DIRECTIONS

Insulin signaling has been involved in tau phosphorylation and amyloid β (Aβ) metabolism. However, it has also been demonstrated that Aβ oligomers can bind to insulin receptors, triggering their internalization, decreasing neuron responsiveness to insulin, and promoting insulin I/R. Thus, it could be argued that Aβ could be a convergent factor in the development of both pathologies. Antioxid. Redox Signal. 26, 542-560.

Chronic condition as a mediator between metabolic syndrome and cognition among community-dwelling older adults: The moderating role of sex

AIM

Metabolic syndrome and chronic conditions are significant predictors of cognition; however, few studies have examined how they work together in predicting cognition in old age. Therefore, the present study examines whether a chronic condition mediates the association between metabolic syndrome and cognition. In addition, it discusses the moderating role of sex in the relationships between metabolic syndrome, chronic conditions and cognition.

METHODS

Secondary analysis was carried out of data from the Malaysian national survey that involved 2322 community residents aged 60 years or older in Peninsular Malaysia. Cognition was measured by the digit symbol substitution test. Metabolic syndrome was assessed by five biomarkers: triglyceride, fasting blood sugar, systolic blood pressure, cholesterol ratio and body mass index. Chronic conditions were assessed by self-reported medical history. The structural equation modeling technique was used to analyze the mediation and moderation tests.

RESULTS

The number of chronic conditions partially mediated the association between metabolic syndrome and cognition. Men and women did not differ in the relationship between metabolic syndrome and cognition; however, the number of chronic conditions was found to be negatively associated with cognition in older women, but not in men.

CONCLUSIONS

Metabolic syndrome might increase the likelihood of older adults to suffer from more chronic conditions; these responses might reduce their cognition. To prevent cognitive decline in old age, specific intervention to minimize the number of chronic conditions by reducing their vascular risk factors is warranted, especially among older women. Geriatr Gerontol Int 2017; 17: 1914-1920.

Metabolic syndrome, hypertension, and nervous system injury: Epidemiological correlates

Metabolic syndrome (MetS) is a common and complex disorder combining hypertension, obesity, dyslipidemia, and insulin resistance. MetS represents a risk factor for changes in cognitive functions in older age, and several studies have suggested that MetS may be linked to dementia. This article reviews the main evidences about the relationship between MetS and neurodegenerative disease. Starting from an epidemiological point of view, the article analyzes medico-social aspects related to MetS, considering the reduction of work capacity and the condition of disability that it involves. Some authors affirm that on the basis of current Italian legislation, it is possible to consider the syndrome as a disability. This is because all the diseases that make up MetS are high-risk clinical pathological conditions. For these reasons, a joint action is required to contain the incidence of MetS, the high social costs, and the loss of productivity related to the syndrome. In conclusion, healthcare initiatives could be adopted in order to increase the understanding of the pathogenic contributions of each element on MetS and how they can be modified. These actions will be useful to reduce healthcare costs and can lead to more effective prevention of metabolic disease, thus promoting good health.

ABBREVIATIONS

MetS: Metabolic syndrome; WHO: World Health Organization; CVD: cerebrovascular diseases; AD: Alzheimer's Disease; VaD: Vascular Dementia; IDF: International Diabetes Federation; T2DM: type 2 diabetes mellitus; CAD: coronary artery disease; MCI: mild cognitive impairment; NCDs: Non Communicable Diseases; BMI: Body Mass Index; ICIDH: International classification of impairments, disabilities and handicaps.

The metabolic syndrome and 10-year cognitive and functional decline in very old men. A population-based study

OBJECTIVES

To describe longitudinal relationships of metabolic syndrome (MetS) to cognitive decline and functional disability in a sample of older non-institutionalized men.

METHODS

data from 1991 to 2000 of the Italian cohorts of the Finland, Italy, the Netherlands, Elderly (FINE) study, were used. Global cognitive function and functional disability, defined as limitations in mobility, basic (ADLs) and instrumental activities of daily living (IADLs) were screened in 1991 and 2000. MetS was defined according to the NCEP ATP-III criteria.

RESULTS

The study sample consisted of 195 men, baseline age 76.1±3.1years. Baseline MetS was prospectively associated with greater 10-year cognitive and functional decline in ADLs and IADLs. After multiple adjustment including age, education, marital status, ApoE ε4 allele, cerebrovascular disease and initial cognitive and depressive status, MetS predicted cognitive decline (B=-1.684, 95%CI=-2.202 to -1.167, p<0.001) and risk of IADLs (OR=1.09, 95% CI=1.01-1.20, p=0.048) and ADLs disability (OR=1.35, 95%CI=1.12-1.62, p<0.001). Interestingly, such associations were not attributable to individual altered components of MetS nor to their sum. Incident disability in ADLs and IADLs were not explained by parallel decline in cognitive function.

CONCLUSIONS

MetS as an entity was associated with accelerated cognitive and functional decline in a population-based sample of very old men.

Metabolic Syndrome and Mild Cognitive Impairment: A Case-Control Study among Elderly in a Shanghai Suburb

BACKGROUND

Metabolic syndrome (MetS) maybe associated with mild cognitive impairment (MCI).

OBJECTIVE

To investigate the relationship between MetS, with its individual or combined components, and MCI among elderly.

METHODS

A case-control study was conducted among the elderly aged 65 years and over in a community located in the southwestern suburb of Shanghai, China. The Chinese version of the Mini-Mental Status Examination (C-MMSE) was used to screen subjects with MCI. Associations of MetS with its individual or combined components and MCI were analyzed using conditional regression analyses with or without adjustment for gender, education, current smoking, current drinking, and physical activities.

RESULTS

There were 379 subjects with MCI and 379 gender- and age-matched healthy controls in the study. Compared with healthy controls in univariate analyses, subjects with MCI were more likely to have less time spent on physical activity, lower C-MMSE score, heavier weight, larger waistline and hipline, higher diastolic blood pressure, higher body mass index, higher abdominal obesity index, higher serum glycated hemoglobin, higher serum triglycerides, higher serum cholesterol, higher serum uric acid, and higher serum alanine aminotransferase. After multivariable adjustment, MetS was significantly associated with an increased risk of MCI (OR = 2.277; 95% CI: 1.086-4.773). Among MetS components, abdominal obesity (OR = 2.101; 95% CI: 1.224-3.608) and hypertension (OR = 2.075; 95% CI: 1.170-3.678) showed a significant association with MCI, respectively; while these two components were combined, the association was stronger (OR = 2.459; 95% CI: 1.360-4.447).

CONCLUSION

MetS and its components, particularly abdominal obesity and hypertension, were found to be significantly associated with the risk of MCI.

Impact of Hypertension on Cognitive Function: A Scientific Statement From the American Heart Association

BACKGROUND

Age-related dementia, most commonly caused by Alzheimer disease or cerebrovascular factors (vascular dementia), is a major public health threat. Chronic arterial hypertension is a well-established risk factor for both types of dementia, but the link between hypertension and its treatment and cognition remains poorly understood. In this scientific statement, a multidisciplinary team of experts examines the impact of hypertension on cognition to assess the state of the knowledge, to identify gaps, and to provide future directions.

METHODS

Authors with relevant expertise were selected to contribute to this statement in accordance with the American Heart Association conflict-of-interest management policy. Panel members were assigned topics relevant to their areas of expertise, reviewed the literature, and summarized the available data.

RESULTS

Hypertension disrupts the structure and function of cerebral blood vessels, leads to ischemic damage of white matter regions critical for cognitive function, and may promote Alzheimer pathology. There is strong evidence of a deleterious influence of midlife hypertension on late-life cognitive function, but the cognitive impact of late-life hypertension is less clear. Observational studies demonstrated a cumulative effect of hypertension on cerebrovascular damage, but evidence from clinical trials that antihypertensive treatment improves cognition is not conclusive.

CONCLUSIONS

After carefully reviewing the literature, the group concluded that there were insufficient data to make evidence-based recommendations. However, judicious treatment of hypertension, taking into account goals of care and individual characteristics (eg, age and comorbidities), seems justified to safeguard vascular health and, as a consequence, brain health.

Cognitive disorders in diabetic patients

This chapter gives an overview of the literature on cognitive dysfunction in adults with type 1 or type 2 diabetes. First, methods to evaluate cognitive functioning and the pattern and severity of cognitive dysfunction in relation to diabetes will be discussed. The reader will note that diabetes is associated with worse cognitive functioning and an increased dementia risk. Next, diabetes-associated abnormalities on brain MRI, including reductions in brain volume - i.e., cerebral atrophy - and vascular lesions, will be addressed. At the group level there are clear relations between these imaging abnormalities and cognitive dysfunction, but at the level of the individual patient these relations are often less clear. Subsequently, risk factors for cognitive performance will be discussed. Evidently, these risk factors are related to diabetes type and the age of the patients involved. For type 1 diabetes, an early age at diabetes onset is the most consistent risk factor, whereas in type 2 diabetes, vascular risk factors and vascular comorbidities are consistent indicators of increased risk. The final section of the chapter addresses possible preventive and treatment measures and implications for daily care.

Insulin resistance and carotid intima-media thickness mediate the association between resting-state heart rate variability and executive function: A path modelling study

BACKGROUND

Research has linked high-frequency heart rate variability (HF-HRV) to cognitive function. The present study adopts a modern path modelling approach to understand potential causal pathways that may underpin this relationship.

METHODS

Here we examine the association between resting-state HF-HRV and executive function in a large sample of civil servants from Brazil (N=8114) recruited for the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). HF-HRV was calculated from 10-min resting-state electrocardiograms. Executive function was assessed using the trail-making test (version B).

RESULTS AND CONCLUSIONS

Insulin resistance (a marker of type 2 diabetes mellitus) and carotid intima-media thickness (subclinical atherosclerosis) mediated the relationship between HRV and executive function in seriatim. A limitation of the present study is its cross-sectional design; therefore, conclusions must be confirmed in longitudinal study. Nevertheless, findings support that possibility that HRV provides a 'spark' that initiates a cascade of adverse downstream effects that subsequently leads to cognitive impairment.

Association between upper leg length and metabolic syndrome among US elderly participants-results from the NHANES (2009-2010)

OBJECTIVE

To examine the relationship between upper leg length (ULL) and metabolic syndrome (MetS) in older adults.

METHODS

Data was collected from National Health and Nutritional Examination Survey (NHANES, 2009-2010). 786 individuals (385 males and 401 females) who were 60 years of age or older were included in this analysis. MetS was defined as having at least three of following conditions, i.e., central obesity, dyslipidemia, insulin resistance, and hypertension based on National Cholesterol Education Program guidelines. ULL was grouped into gender-specific tertiles.

RESULTS

328 (41.7%) of participants were categorized as having MetS (38.7% in men and 49.1% in women, P = 0.002). Compared to individuals in the 1(st) tertile (T1) of ULL, those in the 3(rd) tertile (T3) had lower levels of triglycerides (120.8 vs. 153.1 mg/dL, P = 0.045), waist circumference (100.7 vs. 104.2 cm, P = 0.049), and systolic blood pressure (126.7 vs. 131.4 mmHg, P = 0.005), but higher levels of high-density-lipoprotein cholesterol (58.1 vs. 52.4 mg/dL, P = 0.024). The odds ratios (95% CI) of MetS from multivariate logistic regression were 0.57 (0.32-1.03) for individuals in the T2 of ULL and 0.39 (0.24-0.64) for individuals in the T3 of ULL, respectively (P-value for the trend 0.022).

CONCLUSIONS

ULL was negatively associated with MetS in older adults. Further research is needed to identify potential mechanisms.

Effectiveness of a fotonovela for reducing depression and stress in Latino dementia family caregivers

The clinical need to address stress and depression in Latino dementia caregivers (CGs) combined with low health literacy and less accurate knowledge of dementia motivated the development of a pictorial tool [called a fotonovela (FN)] to teach (a) coping skills for caregiver (CG) stress; (b) self-assessment of depression; and (c) encourage improved utilization of available resources. To test the effectiveness of the FN, 110 of 147 Latino CGs, who were randomly assigned to the Fotonovela Condition (FNC) or the Usual Information Condition (UIC), were included in the final analyses. Self-report measures were given at baseline and post intervention. Results showed that FNC CGs demonstrated significantly greater reductions in level of depressive symptoms than UIC CGs. A significant decrease in level of stress due to memory and behavioral problems exhibited by their loved ones was similar in both groups. The FNC CGs reported that the FN was more helpful and that they referred to it more often than the UIC CGs did with regard to the informational materials they were provided about dementia. In conclusion, a culturally tailored FN can be an effective tool for Latino CGs given their high unmet needs for assistance and various barriers in accessing resources.

Impact of Nutrition on Cerebral Circulation and Cognition in the Metabolic Syndrome

The increasing prevalence of Metabolic Syndrome (MetS), defined as the clustering of abdominal obesity, dyslipidemia, hypertension, and hyperglycemia, appears to be driving the global epidemics cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM). Nutrition has a major impact on MetS and plays an important role in the prevention, development, and treatment of its features. Structural and functional alterations in the vasculature, associated with MetS, might form the link between MetS and the increased risk of developing CVD and T2DM. Not only does the peripheral vasculature seem to be affected, but the syndrome has a profound impact on the cerebral circulation and thence brain structure as well. Furthermore, strong associations are shown with stroke, cognitive impairment, and dementia. In this review the impact of nutrition on the individual components of MetS, the effects of MetS on peripheral and cerebral vasculature, and its consequences for brain structure and function will be discussed.

Glycemic control, inflammation, and cognitive function in older patients with type 2 diabetes

OBJECTIVE

Glycated hemoglobin (HbA1c) and C-reactive protein (CRP) have been associated with cognitive impairment independently. However, it is unclear if their combination exacerbates poor cognitive function. We assessed whether long-term glycemic level and glycemic variability modulate the association of systemic inflammation with cognitive function, in a sample of cognitively normal older people with type 2 diabetes.

METHODS

A retrospective cohort study of 777 randomly selected participants from ~11,000 patients in the Maccabi Healthcare Services Diabetes Registry, as part of the Israel Diabetes and Cognitive Decline study. Subjects averaged 18 (±9.4) HbA1c measures in the Maccabi Healthcare Services Registry, which were used to calculate long-term glycemic level (HbA1c-mean) and glycemic variability (HbA1c-standard deviation (SD)). Linear regression models assessed the interactions of CRP, a marker of systemic inflammation, with HbA1c-mean and HbA1c-SD on subjects' performance in tests of Memory, Executive Functions, Attention, and Semantic Categorization.

RESULTS

Quadratic interactions of CRP with HbA1c-SD approached significance for executive functions and overall cognition. However, after Bonferroni adjustment, none of the interactions of CRP with HbA1c were statistically significant. In partial correlations according to HbA1c-SD tertiles, CRP was weakly correlated in the middle tertile with decreased performance in the domains of semantic categorization (r = -0.166, p = 0.011), executive functions (r = -0.136, p = 0.038), and overall cognition (r = -0.157, p = 0.016).

CONCLUSIONS

Glycated hemoglobin does not substantially modulate the association of CRP with cognition in a sample of cognitively normal, community dwelling older people with relatively well-managed type 2 diabetes.

Hot Topics in Research: Preventive Neuroradiology in Brain Aging and Cognitive Decline

Preventive neuroradiology is a new concept supported by growing literature. The main rationale of preventive neuroradiology is the application of multimodal brain imaging toward early and subclinical detection of brain disease and subsequent preventive actions through identification of modifiable risk factors. An insightful example of this is in the area of age-related cognitive decline, mild cognitive impairment, and dementia with potentially modifiable risk factors such as obesity, diet, sleep, hypertension, diabetes, depression, supplementation, smoking, and physical activity. In studying this link between lifestyle and cognitive decline, brain imaging markers may be instrumental as quantitative measures or even indicators of early disease. The purpose of this article is to provide an overview of the major studies reflecting how lifestyle factors affect the brain and cognition aging. In this hot topics review, we will specifically focus on obesity and physical activity.

Evidence of a cumulative effect of cardiometabolic disorders at midlife and subsequent cognitive function

BACKGROUND

longitudinal data as regards the link between the cumulative effect of cardiometabolic disorders and cognition are relatively scant and heterogeneous.

OBJECTIVE

we examined the cross-time associations of MetS status with cognitive performance in ageing adults.

DESIGN AND METHODS

using data from the French SU.VI.MAX cohort, we studied 2,788 adults. The presence of abdominal obesity, hyperglycaemia, dyslipidaemia and elevated blood pressure was clinically evaluated in 1994-96. Cognitive performance was assessed after a mean of 13 years via a battery of six validated instruments. The standardised individual test scores were summed up to provide a composite cognitive performance measure; principal component analysis was performed to define performance scores on verbal memory and executive functioning. Associations between MetS and subsequent cognitive performance were examined via ANCOVA, providing estimates of mean difference and corresponding 95% confidence intervals (CI).

RESULTS

MetS status at midlife was not associated with subsequent cognitive function. However, a 1-unit increase in the number of cardiometabolic disorders present was associated with a decrease in the composite cognitive score (mean difference = -0.36; 95% CI: -0.68, -0.05). Significant associations were also found with several cardiometabolic disorders (hyperglycaemia, central obesity and dyslipidaemia) and specific cognitive domains.

CONCLUSION

this study supports the existence of a cross-time, cumulative effect of cardiometabolic disorders present at midlife and subsequent cognitive performance. Given the worldwide population ageing and the increase in MetS prevalence, there is an urgent need for recommendations as regards cognitive ageing.

Vascular contributions to cognitive impairment

Unlike many neurodegenerative causes of cognitive impairment and dementia, vascular damage is preventable. Despite the heterogeneity of vascular cognitive impairment (VCI) and the complexity of its clinical presentations, the potential for limiting progression and changing the trajectory of damage makes it all the more important for physicians to be educated about the syndrome and to remain vigilant when taking care of patients. In this review, we outline an approach to patients with possible VCI, summarize current treatment and prevention guidelines, and provide an overview with case examples.

Depressive symptoms, cognitive impairment, and metabolic syndrome in community-dwelling elderly in Southern Taiwan

OBJECTIVE

Metabolic syndrome and depression are both thought to be associated with cognitive impairment in the elderly. Metabolic syndrome is also correlated with depression. We examined their possible pathways in a population-based sample.

METHODS

We recruited 300 older community participants from Southern Taiwan. Demographics, medical history, severity of depressive symptoms, cognitive function, apolipoprotein genotyping, and lipid profile were collected. The presence of metabolic syndrome was confirmed with the Third Report of the National Cholesterol Education Program's Adult Treatment Panel. Possible relationships between metabolic syndrome, depressive symptoms, and cognitive dysfunction were explored using logistic regression and structured equation modelling.

RESULTS

When gender, age, education, marital status, and apolipoprotein genotype were adjusted for logistic regression, metabolic syndrome and depressive symptoms were independent and significant predictors of cognitive dysfunction for community-dwelling elderly. In structural equation modelling, metabolic syndrome and depressive symptoms were correlated to each other, and both contributed to the presence of cognitive dysfunction.

CONCLUSIONS

Depressive symptoms and metabolic syndrome are independently associated with cognitive impairment among community-dwelling elderly.

Is there an association between metabolic syndrome and cognitive function in very old adults? The Newcastle 85+ Study

OBJECTIVES

To determine, using data from the Newcastle 85+ Study, whether there is an association between modern diagnostic criteria for metabolic syndrome (MetS) and cognitive function in very old adults (≥85) and whether inflammation, physical activity, or diabetes mellitus status affects this association.

DESIGN

Longitudinal, population-based cohort study.

SETTING

Newcastle and North Tyneside, United Kingdom.

PARTICIPANTS

Community-dwelling and institutionalized men and women recruited through general practices (N = 845).

MEASUREMENTS

MetS was defined according to the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) criteria. Cross-sectional and prospective (up to 5 years of follow-up) associations between MetS and global cognitive function (assessed using the Mini-Mental State Examination (MMSE)) and between MetS and attention and episodic memory (assessed using the Cognitive Drug Research battery) were performed.

RESULTS

MetS was not associated with cognitive function at baseline or cognitive change over time. Lack of association was not because MetS was predictive of subsequent mortality. Of the individual components of the MetS criteria, high blood pressure was associated with better cognitive function at baseline (MMSE: β (standard error (SE)) = -0.716 (0.152), P < .001), and low high-density lipoprotein cholesterol was associated with poorer global cognitive function at baseline (MMSE: 0.436 (0.131), P = .001).

CONCLUSION

The association between MetS and cognitive decline, which has been described in younger populations (<75), was not apparent in this population of individuals aged 85 and older at baseline.

Abdominal obesity contributes to neurocognitive impairment in HIV-infected patients with increased inflammation and immune activation

OBJECTIVE

We tested our hypothesis that abdominal obesity when associated with increased levels of systemic and central nervous system immunoinflammatory mediators contributes to neurocognitive impairment (NCI).

DESIGN

Cross-sectional.

SETTING

Six Academic Centers.

PARTICIPANTS

One hundred fifty-two patients with plasma HIV RNA <1000 copies per milliliter had clinical evaluations and cognitive function quantified by global deficit scores (GDS).

OUTCOME MEASURES

GDS, waist circumference (WC) and plasma IL-6, sCD163, and sCD14 and CSF sCD40L, sTNFrII, MCP-1, sICAM, and MMP-9.

RESULTS

WC and plasma IL-6 levels positively correlated with GDS; the WC correlation was strongest in the high tertile of IL-6 (ρ = 0.39, P = 0.005). IL-6 correlated with GDS only if WC was ≥99 cm. In the high tertile of CSF sCD40L, a biomarker of macrophage and microglial activation, the correlation of IL-6 to GDS was strongest (ρ = 0.60, P < 0.0001). Across 3-5 visits within ±1 year of the index visit, GDS remained worse in patients with IL-6 levels in the high versus low tertile (P = 0.02). Path analysis to explore potential mediators of NCI produced a strong integrated model for patients in the high CSF sCD40L tertile. In this model, WC affected GDS both directly and through a second path that was mediated by IL-6. Inclusion of plasma sCD14 levels strengthened the model. NCI was more common in men and for individuals with components of the metabolic syndrome.

CONCLUSIONS

Neurocognitive function was significantly linked to abdominal obesity, systemic inflammation (high IL-6), and immune activation in plasma (high sCD14) and CSF (high sCD40L). Abdominal obesity, inflammation, and central nervous system immune activation are potential therapeutic targets for NCI in HIV-positive patients.

Effects of metabolic syndrome on language functions in aging

This study explored effects of the metabolic syndrome (MetS) on language in aging. MetS is a constellation of five vascular and metabolic risk factors associated with the development of chronic diseases and increased risk of mortality, as well as brain and cognitive impairments. We tested 281 English-speaking older adults aged 55-84, free of stroke and dementia. Presence of MetS was based on the harmonized criteria (Alberti et al., 2009). Language performance was assessed by measures of accuracy and reaction time on two tasks of lexical retrieval and two tasks of sentence processing. Regression analyses, adjusted for age, education, gender, diabetes, hypertension, and heart disease, demonstrated that participants with MetS had significantly lower accuracy on measures of lexical retrieval (action naming) and sentence processing (embedded sentences, both subject and object relative clauses). Reaction time was slightly faster on the test of embedded sentences among those with MetS. MetS adversely affects the language performance of older adults, impairing accuracy of both lexical retrieval and sentence processing. This finding reinforces and extends results of earlier research documenting the negative influence of potentially treatable medical conditions (diabetes, hypertension) on language performance in aging. The unanticipated finding that persons with MetS were faster in processing embedded sentences may represent an impairment of timing functions among older individuals with MetS.

Cellular and metabolic alterations in the hippocampus caused by insulin signalling dysfunction and its association with cognitive impairment during aging and Alzheimer's disease: studies in animal models

A growing body of animal and epidemiological studies suggest that metabolic diseases such as obesity, insulin resistance, metabolic syndrome and type 2 diabetes mellitus are associated with the development of cognitive impairment, dementia and Alzheimer's disease, particularly in aging. Several lines of evidence suggest that insulin signalling dysfunction produces these metabolic alterations and underlie the development of these neurodegenerative diseases. In this article, we address normal insulin function in the synapse; we review and discuss the physiopathological hallmarks of synaptic insulin signalling dysfunction associated with metabolic alterations. Additionally, we describe and review the major animal models of obesity, insulin resistance, metabolic syndrome and type 2 diabetes mellitus. The comprehensive knowledge of the molecular mechanisms behind the association of metabolic alterations and cognitive impairment could facilitate the early detection of neurodegenerative diseases in patients with metabolic alterations, with treatment that focus on neuroprotection. It could also help in the development of metabolic-based therapies and drugs for using in dementia and Alzheimer's disease patients to alleviate their symptoms in a more efficient and comprehensive way.

Physical activity, body mass index, and brain atrophy in Alzheimer's disease

The purpose of this study was to use a novel imaging biomarker to assess associations between physical activity (PA), body mass index (BMI), and brain structure in normal aging, mild cognitive impairment, and Alzheimer's dementia. We studied 963 participants (mean age: 74.1 ± 4.4 years) from the multisite Cardiovascular Health Study including healthy controls (n = 724), Alzheimer's dementia patients (n = 104), and people with mild cognitive impairment (n = 135). Volumetric brain images were processed using tensor-based morphometry to analyze regional brain volumes. We regressed the local brain tissue volume on reported PA and computed BMI, and performed conjunction analyses using both variables. Covariates included age, sex, and study site. PA was independently associated with greater whole brain and regional brain volumes and reduced ventricular dilation. People with higher BMI had lower whole brain and regional brain volumes. A PA-BMI conjunction analysis showed brain preservation with PA and volume loss with increased BMI in overlapping brain regions. In one of the largest voxel-based cross-sectional studies to date, PA and lower BMI may be beneficial to the brain across the spectrum of aging and neurodegeneration.

Stability in Cognitive Function Over 18 Years: Prevalence and Predictors among Older Mexican Americans

PURPOSE

Numerous studies have examined the association of physical, behavioral and social factors with cognitive decline in older adults. Less attention has been placed on factors associated with long-term maintenance of intact cognition even into very old age. A greater understanding of those factors can inform the development of activities for maintaining cognitive strength.

METHODS

Using a sample from the Hispanic Established Populations for Epidemiologic Study of the Elderly, a population-based study of non-institutionalized Mexican Americans aged 65 and older from five Southwestern states (N = 2767), latent class mixture models were developed to identify subgroups of cognitive change over time.

RESULTS

Three distinct trajectories of cognitive change were identified and characterized as stable, slow decline and rapid decline. Compared to the rapid decline group, a higher proportion of the stable cognition group were women, had high school education, were married and attended church one or more times per week. Regular church attendance had a significant positive impact in the stable group (β = 0.64, p <0.01), the slow decline group (β = 0.84, p <0.001) and the rapid decline group (β = 2.50, p <0.001). Activity limitations had a consistently negative association with cognition in the stable, slow decline and rapid decline groups (β = -0.37, p <0.001; β = -0.85, p <0.001; and β = -1.58, p <0.001 respectively).

CONCLUSION

Substantial heterogeneity exists in rates of cognitive decline among older Mexican Americans. Interventions targeting cognitive maintenance may benefit from increased focus on factors associated with continued social engagement.

Childhood and adolescent obesity and long-term cognitive consequences during aging

The prevalence of childhood/adolescent obesity and insulin resistance has reached an epidemic level. Obesity's immediate clinical impacts have been extensively studied; however, current clinical evidence underscores the long-term implications. The current study explored the impacts of brief childhood/adolescent obesity and insulin resistance on cognitive function in later life. To mimic childhood/adolescent obesity and insulin resistance, we exposed 9-week-old C57BL/6J mice to a high-fat diet for 15 weeks, after which the mice exhibited diet-induced obesity and insulin resistance. We then put these mice back on a normal low-fat diet, after which the mice exhibited normal body weight and glucose tolerance. However, a spatial memory test in the forms of the Morris water maze (MWM) and contextual fear conditioning at 85 weeks of age showed that these mice had severe deficits in learning and long-term memory consolidation. Mechanistic investigations identified increased expression of histone deacetylases 5, accompanied by reduced expression of brain-derived neurotrophic factor, in the brains 61 weeks after the mice had been off the high-fat diet. Electrophysiology studies showed that hippocampal slices isolated from these mice are more susceptible to synaptic impairments compared with slices isolated from the control mice. We demonstrated that a 15-week occurrence of obesity and insulin resistance during childhood/adolescence induces irreversible epigenetic modifications in the brain that persist following restoration of normal metabolic homeostasis, leading to brain synaptic dysfunction during aging. Our study provides experimental evidence that limited early-life exposure to obesity and insulin resistance may have long-term deleterious consequences in the brain, contributing to the onset/progression of cognitive dysfunction during aging.

Obesity and dementia: adipokines interact with the brain

Obesity is a pandemic and a serious global health concern. Obesity is a risk factor for multiple conditions and contributes to multi-morbidities, resulting in increased health costs and millions of deaths each year. Obesity has been associated with changes in brain structure, cognitive deficits, dementia and Alzheimer׳s disease. Adipokines, defined as hormones, cytokines and peptides secreted by adipose tissue, may have more widespread influence and functionality in the brain than previously thought. In this review, six adipokines, and their actions in the obese and non-obese conditions will be discussed. Included are: plasminogen activator inhibitor-1 (PAI-1), interleukin-6 (IL-6), tumor necrosis factors alpha (TNF-α), angiotensinogen (AGT), adiponectin and leptin. Their functionality in the periphery, their ability to cross the blood brain barrier (BBB) and their influence on dementia processes within the brain will be discussed.

Modeling metabolic syndrome and its association with cognition: the Northern Manhattan study

Metabolic syndrome (MetS) is a clustering of vascular risk factors and is associated with increased risk of cardiovascular disease. Less is known about the relationship between MetS and cognition. We examined component vascular risk factors of MetS as correlates of different cognitive domains. The Northern Manhattan Study (NOMAS) includes 1290 stroke-free participants from a largely Hispanic multi-ethnic urban community. We used structural equation modeling (SEM) to model latent variables of MetS, assessed at baseline and an average of 10 years later, at which time participants also underwent a full cognitive battery. The two four-factor models, of the metabolic syndrome (blood pressure, lipid levels, obesity, and fasting glucose) and of cognition (language, executive function, psychomotor, and memory), were each well supported (CFI=0.97 and CFI=0.95, respectively). When the two models were combined, the correlation between metabolic syndrome and cognition was -.31. Among the metabolic syndrome components, only blood pressure uniquely predicted all four cognitive domains. After adjusting for age, gender, race/ethnicity, education, smoking, alcohol, and risk factor treatment variables, blood pressure remained a significant correlate of all domains except memory. In this stroke-free race/ethnically diverse community-based cohort, MetS was associated with cognitive function suggesting that MetS and its components may be important predictors of cognitive outcomes. After adjusting for sociodemographic and vascular risk factors, blood pressure was the strongest correlate of cognitive performance. Findings suggest MetS, and in particular blood pressure, may represent markers of vascular or neurodegenerative damage in aging populations.

Association of subsyndromal and depressive symptoms with inflammatory markers among different ethnic groups: the multi-ethnic study of atherosclerosis (MESA)

OBJECTIVE

Depressive symptoms are associated with inflammation yet the association between inflammation and different levels of depression remains unclear. Therefore, we studied the association of subsyndromal and depressive symptoms with inflammatory markers in a large multi-ethnic cohort.

METHODS

C-reactive protein (CRP) (n=6269), interleukin-6 (IL-6) (n=6135) and tumor necrosis factor-alpha (TNF-α) (n=1830) were measured in selected participants from the multi-ethnic study of atherosclerosis (MESA). Subsyndromal depressive symptoms were defined as a CES-D value from 8 to 15, depressive symptoms as a CES-D≥16 and normal as a CES-D≤7. Depressive states (subsyndromal and depressed) were entered into multivariable linear regression models incrementally adjusting for demographic, behavioral, biologic and comorbidities.

RESULTS

Among 6289 participants not taking antidepressants and free from CVD, the mean age was 62.2, while 52% were women, 36.4% were Caucasian, 28.9% African-American, 22.3% Hispanics and 12.4% Chinese-American. Of the total, 24.2% had subsyndromal depression and 11.8% had depressive symptoms. Compared to the non-depressed group and after controlling for demographics, there was no association between both subsyndromal and depressive symptoms with logCRP (β=-0.01, p=0.80 and β=-0.05, p=0.25 respectively), logIL-6 (β=0.01, p=0.71 and β=-0.04, p=0.07 respectively) and logTNF-α (β=-0.03, p=0.29 and β=0.06, p=0.18 respectively). Moreover, fully adjusted models showed no significant associations for logIL-6 and logTNF-α and the different depressive categories. However, with full adjustment, we found a significant inverse association between depressive symptoms and lnCRP (β=-0.10, p=0.01) that was not present for subsyndromal depression (β=-0.05, p=0.11).

CONCLUSION

Among participants not taking anti-depressants, subsyndromal depression is not associated with inflammation. However, depressive symptoms measured by CES-D≥16 are associated with a lower inflammation (CRP).

Longitudinal inflammation, cognitive decline, and Alzheimer's disease: a mini-review

The role of inflammation in cognitive decline has generated considerable interest, although few longitudinal evaluations have been conducted. A review of the literature yields mixed findings but suggests that inflammatory dysregulation is evident and may be related to clinical outcomes. The directionality, magnitude, and progression of these associations remain unclear. Future studies employing multiple time points of inflammatory data along with Alzheimer's disease (AD) biomarkers are critical for explication of longitudinal inflammation in cognitive decline.

Association of vascular risk factors with cognition in a multiethnic sample

OBJECTIVES

To examine the relationship between cardiovascular risk factors (CVRFs) and cognitive performance in a multiethnic sample of older adults.

METHOD

We used longitudinal data from the Washington Heights-Inwood Columbia Aging Project. A composite score including smoking, stroke, heart disease, diabetes, hypertension, and central obesity represented CVRFs. Multiple group parallel process multivariate random effects regression models were used to model cognitive functioning and examine the contribution of CVRFs to baseline performance and change in general cognitive processing, memory, and executive functioning.

RESULTS

Presence of each CVRF was associated with a 0.1 SD lower score in general cognitive processing, memory, and executive functioning in black and Hispanic participants relative to whites. Baseline CVRFs were associated with poorer baseline cognitive performances among black women and Hispanic men. CVRF increase was related to baseline cognitive performance only among Hispanics. CVRFs were not related to cognitive decline. After adjustment for medications, CVRFs were not associated with cognition in Hispanic participants.

DISCUSSION

CVRFs are associated with poorer cognitive functioning, but not cognitive decline, among minority older adults. These relationships vary by gender and medication use. Consideration of unique racial, ethnic, and cultural factors is needed when examining relationships between CVRFs and cognition.

Alzheimer's disease and type 2 diabetes: multiple mechanisms contribute to interactions

Obesity, metabolic syndrome, and type 2 diabetes (T2D) are related disorders with widespread deleterious effects throughout the body. One important target of damage is the brain. Persons with metabolic disorders are at significantly increased risk for cognitive decline and the development of vascular dementia and Alzheimer's disease. Our review of available evidence from epidemiologic, clinical, and basic research suggests that neural dysfunction from T2D-related disease results from several underlying mechanisms, including metabolic, inflammatory, vascular, and oxidative changes. The relationships between T2D and neural dysfunction are regulated by several modifiers. We emphasize 2 such modifiers, the genetic risk factor apolipoprotein E and an age-related endocrine change, low testosterone. Both factors are independent risk factors for Alzheimer's disease that may also cooperatively regulate pathologic interactions between T2D and dementia. Continued elucidation of the links between metabolic disorders and neural dysfunction promises to foster the development of effective therapeutic strategies.

The impact of glucose disorders on cognition and brain volumes in the elderly: the Sydney Memory and Ageing Study

Type 2 diabetes predicts accelerated cognitive decline and brain atrophy. We hypothesized that impaired fasting glucose (IFG) and incident glucose disorders have detrimental effects on global cognition and brain volume. We further hypothesized that metabolic and inflammatory derangements accompanying hyperglycaemia contribute to change in brain structure and function. This was a longitudinal study of a community-dwelling elderly cohort with neuropsychological testing (n = 880) and brain volumes by magnetic resonance imaging (n = 312) measured at baseline and 2 years. Primary outcomes were global cognition and total brain volume. Secondary outcomes were cognitive domains (processing speed, memory, language, visuospatial and executive function) and brain volumes (hippocampal, parahippocampal, precuneus and frontal lobe). Participants were categorised as normal, impaired fasting glucose at both assessments (stable IFG), baseline diabetes or incident glucose disorders (incident diabetes or IFG at 2 years). Measures included inflammatory cytokines and oxidative metabolites. Covariates were age, sex, education, non-English speaking background, smoking, blood pressure, lipid-lowering or antihypertensive medications, mood score, apolipoprotein E genotype and baseline cognition or brain volume. Participants with incident glucose disorders had greater decline in global cognition and visuospatial function compared to normal, similar to that observed in baseline diabetes. Homocysteine was independently associated with the observed effect of diabetes on executive function. Apolipoprotein E genotype did not influence the observed effects of diabetes on cognition. Incident glucose disorders and diabetes were also associated with greater 2-year decline in total brain volume, compared to normal (40.0 ± 4.2 vs. 46.7 ± 5.7 mm(3) vs. 18.1 ± 6.2, respectively, p < 0.005). Stable IFG did not show greater decline in global cognition or brain volumes compared to normal. Incident glucose disorders, like diabetes, are associated with accelerated decline in global cognition and brain volumes in non-demented elderly, whereas stable IFG is not. Preventing deterioration in glucose metabolism in the elderly may help preserve brain structure and function.

Epigenetic mechanisms linking diabetes and synaptic impairments

Diabetes is one of the major risk factors for dementia. However, the molecular mechanism underlying the risk of diabetes for dementia is largely unknown. Recent studies revealed that epigenetic modifications may play a role in the pathogenesis of diabetes. We hypothesized that diabetes may cause epigenetic changes in the brain that may adversely affect synaptic function. We found significant elevation in the expression of histone deacetylases (HDACs) class IIa in the brains of diabetic subjects compared with control subjects, and these changes coincide with altered expression of synaptic proteins. In a mouse model of diet-induced type 2 diabetes (T2D), we found that, similar to humans, T2D mice also showed increased expression of HDAC IIa in the brain, and these alterations were associated with increased susceptibility to oligomeric Aβ-induced synaptic impairments in the hippocampal formation and eventually led to synaptic dysfunction. Pharmacological inhibition of HDAC IIa restored synaptic plasticity. Our study demonstrates that diabetes may induce epigenetic modifications affecting neuropathological mechanisms in the brain leading to increased susceptibility to insults associated with neurodegenerative or vascular impairments. Our study provides, for the first time, an epigenetic explanation for the increased risk of diabetic patients developing dementia.

Executive functioning and the metabolic syndrome: a project FRONTIER study

Decrements in cognitive functioning have been linked to the metabolic syndrome (MetS), a risk factor for cardiovascular disease defined by the presence of three of the following: elevated blood pressure, increased waist circumference, elevated blood glucose, elevated triglycerides, and low high-density lipoprotein cholesterol. We examined the relationship between four measures of executive functioning (EF) and MetS as diagnosed by National Heart, Lung, and Blood Institute-American Heart Association criteria. MetS was examined in a rural population of 395 persons with a mean age of 61.3 years, 71.4% women, 37.0% Hispanic, 53.7% White non-Hispanic. There was a 61.0% prevalence of MetS. We derived a factor score from the four executive function measures which was used to compare those with and without the syndrome, as well as any additive effects of components of the syndrome. Those with MetS exhibited significantly poorer performance than those without the syndrome. However, there was no additive effect, having more components of the syndrome was not related to lower performance. The presence of MetS was associated with poorer EF in this rural cohort of community dwelling volunteers.

Subgroup of ADNI normal controls characterized by atrophy and cognitive decline associated with vascular damage

Previous work examining Alzheimer's Disease Neuroimaging Initiative (ADNI) normal controls using cluster analysis identified a subgroup characterized by substantial brain atrophy and white matter hyperintensities (WMH). We hypothesized that these effects could be related to vascular damage. Fifty-three individuals in the suspected vascular cluster (Normal 2) were compared with 31 individuals from the cluster characterized as healthy/typical (Normal 1) on a variety of outcomes, including magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) biomarkers, vascular risk factors and outcomes, cognitive trajectory, and medications for vascular conditions. Normal 2 was significantly older but did not differ on ApoE4+ prevalence. Normal 2 differed significantly from Normal 1 on all MRI measures but not on Amyloid-Beta1-42 or total tau protein. Normal 2 had significantly higher body mass index (BMI), Hachinksi score, and creatinine levels, and took significantly more medications for vascular conditions. Normal 2 had marginally significantly higher triglycerides and blood glucose. Normal 2 had a worse cognitive trajectory on the Rey's Auditory Verbal Learning Test (RAVLT) 30-min delay test and the Functional Activity Questionnaire (FAQ). Cerebral atrophy associated with multiple vascular risks is common among cognitively normal individuals, forming a distinct subgroup with significantly increased cognitive decline. Further studies are needed to determine the clinical impact of these findings.

Metabolic syndrome and cognitive decline in early Alzheimer's disease and healthy older adults

Metabolic syndrome (MetS) is a cluster of risk factors (i.e., abdominal obesity, hypertension, dyslipidemia, glucose and insulin dysregulation) that is associated with cardiovascular disease, diabetes, and dementia. Recent studies addressing the association of MetS with cognitive performance and risk for dementia report mixed results. An important step in clarifying these conflicting results is determining whether cognition is influenced by the effects of individual MetS components versus the additive effects of multiple components. We assessed the effect of MetS on cognitive performance and decline over two years in 75 cases of early Alzheimer's disease (AD) and 73 healthy older adult controls in the Brain Aging Project. Using factor analytic techniques, we compared the effect of a combined MetS factor to the effect of individual MetS components on change in attention, verbal memory, and mental status. In healthy controls, a combined MetS factor did not significantly predict cognitive performance, though higher insulin predicted poorer cognitive performance outcomes. In the AD group, higher scores on a combined MetS factor predicted better cognitive outcomes. Our findings suggest that MetS does not have the same association with cognitive decline in healthy older adults and those with early AD. We suggest that individual MetS components should not be evaluated in isolation and that careful methodological approaches are needed to understand the timing and non-linear relationships among these components over time.