Metabolic cardiovascular syndrome and risk of dementia in Japanese-American elderly men. The Honolulu-Asia aging study

A systematic review/meta-analysis of prevalence and incidence rates illustrates systemic underrepresentation of individuals racialized as Asian and/or Asian-American in ADRD research

We investigate Alzheimer's disease and related dementia (ADRD) prevalence, incidence rate, and risk factors in individuals racialized as Asian and/or Asian-American and assess sample representation. Prevalence, incidence rate, risk factors, and heterogeneity of samples were assessed. Random-effects meta-analysis was conducted, generating pooled estimates. Of 920 records across 14 databases, 45 studies were included. Individuals racialized as Asian and/or Asian-American were mainly from Eastern and Southern Asia, had higher education, and constituted a smaller sample relative to non-Hispanic white cohorts. The average prevalence was 10.9%, ranging from 0.4% to 46%. The average incidence rate was 20.03 (12.01-33.8) per 1000 person-years with a range of 75.19-13.59 (12.89-14.33). Risk factors included physiological, genetic, psychological, behavioral, and social factors. This review underscores the systemic underrepresentation of individuals racialized as Asian and/or Asian-American in ADRD research and the need for inclusive approaches accounting for culture, language, and immigration status. HIGHLIGHTS: There is considerable heterogeneity in the prevalence of ADRD among studies of Asian-Americans. There is limited data on group-specific risk factors for ADRD among Asian-Americans. The average prevalence of (ADRD) among Asian-Americans was found to be 7.4%, with a wide range from 0.5% to 46%.

Sex Disparity in the Association of Metabolic Syndrome with Cognitive Impairment

Background/Objectives: Metabolic syndrome (MS) is a constellation of several cardiometabolic risk factors. We investigated sex disparity in the associations between MS and cognitive impairment using cross-sectional data from Taiwan Biobank. Methods: We determined the associations of MS and its five components with cognitive impairment (mini-mental state examination, MMSE < 24) and the five domains of MMSE using logistic regression analyses. Results: A total of 7399 men and 11,546 women were included, and MS was significantly associated with cognitive impairment only in women (adjusted OR 1.48, 95% CI 1.29-1.71, p = 0.001) (p for interaction 0.005). In women, the association with MS was significant in orientation (adjusted OR 1.21, 95% CI 1.07-1.37, p = 0.003), memory (adjusted OR 1.12, 95% CI 1.01-1.25, p = 0.034) and design copying (adjusted OR 1.41, 95% CI 1.23-1.62, p = 0.001) (p value for interaction 0.039, 0.023, and 0.093, respectively). Among the components of MS, a large waist circumference (adjusted OR 1.25, 95% CI 1.08-1.46, p = 0.003), high fasting glucose (adjusted OR 1.16, 95% CI 1.00-1.34, p = 0.046), and low HDL cholesterol (adjusted OR 1.16, 95% CI 1.00-1.34, p = 0.049) were significantly associated with cognitive impairment in women. Conclusions: Our findings suggest that sex has a significant influence on the association between MS and cognitive dysfunction, especially in orientation and memory.

Investigating the nexus of metabolic syndrome, serum uric acid, and dementia risk: a prospective cohort study

BACKGROUND

The global dementia prevalence is surging, necessitating research into contributing factors. We aimed to investigate the association between metabolic syndrome (MetS), its components, serum uric acid (SUA) levels, and dementia risk.

METHODS

Our prospective study comprised 466,788 participants without pre-existing MetS from the UK Biobank. We confirmed dementia diagnoses based on the ICD-10 criteria (F00-03). To evaluate the dementia risk concerning MetS, its components, and SUA levels, we applied Cox proportional hazards models, while adjusting for demographic factors.

RESULTS

Over a median follow-up of 12.7 years, we identified 6845 dementia cases. Individuals with MetS had a 25% higher risk of all-cause dementia (hazard ratio [HR] = 1.25, 95% confidence interval [CI] = 1.19-1.31). The risk increased with the number of MetS components including central obesity, dyslipidemia for high-density lipoprotein (HDL) cholesterol, hypertension, hyperglycemia, and dyslipidemia for triglycerides. Particularly for those with all five components (HR = 1.76, 95% CI = 1.51-2.04). Dyslipidemia for HDL cholesterol, hypertension, hyperglycemia, and dyslipidemia for triglycerides were independently associated with elevated dementia risk (p < 0.01). MetS was further linked to an increased risk of all-cause dementia (11%) and vascular dementia (VD, 50%) among individuals with SUA levels exceeding 400 μmol/L (all-cause dementia: HR = 1.11, 95% CI = 1.02-1.21; VD: HR = 1.50, 95% CI = 1.28-1.77).

CONCLUSIONS

Our study provides robust evidence supporting the association between MetS, its components, and dementia risk. These findings emphasize the importance of considering MetS and SUA levels in assessing dementia risk, offering valuable insights for prevention and management strategies.

Plasma metabolic profiles predict future dementia and dementia subtypes: a prospective analysis of 274,160 participants

BACKGROUND

Blood-based biomarkers for dementia are gaining attention due to their non-invasive nature and feasibility in regular healthcare settings. Here, we explored the associations between 249 metabolites with all-cause dementia (ACD), Alzheimer's disease (AD), and vascular dementia (VaD) and assessed their predictive potential.

METHODS

This study included 274,160 participants from the UK Biobank. Cox proportional hazard models were employed to investigate longitudinal associations between metabolites and dementia. The importance of these metabolites was quantified using machine learning algorithms, and a metabolic risk score (MetRS) was subsequently developed for each dementia type. We further investigated how MetRS stratified the risk of dementia onset and assessed its predictive performance, both alone and in combination with demographic and cognitive predictors.

RESULTS

During a median follow-up of 14.01 years, 5274 participants developed dementia. Of the 249 metabolites examined, 143 were significantly associated with incident ACD, 130 with AD, and 140 with VaD. Among metabolites significantly associated with dementia, lipoprotein lipid concentrations, linoleic acid, sphingomyelin, glucose, and branched-chain amino acids ranked top in importance. Individuals within the top tertile of MetRS faced a significantly greater risk of developing dementia than those in the lowest tertile. When MetRS was combined with demographic and cognitive predictors, the model yielded the area under the receiver operating characteristic curve (AUC) values of 0.857 for ACD, 0.861 for AD, and 0.873 for VaD.

CONCLUSIONS

We conducted the largest metabolome investigation of dementia to date, for the first time revealed the metabolite importance ranking, and highlighted the contribution of plasma metabolites for dementia prediction.

Enabling Lipidomic Biomarker Studies for Protected Populations by Combining Noninvasive Fingerprint Sampling with MS Analysis and Machine Learning

Triacylglycerols and wax esters are two lipid classes that have been linked to diseases, including autism, Alzheimer's disease, dementia, cardiovascular disease, dry eye disease, and diabetes, and thus are molecules worthy of biomarker exploration studies. Since triacylglycerols and wax esters make up the majority of skin-surface lipid secretions, a viable sampling method for these potential biomarkers would be that of groomed latent fingerprints. Currently, however, blood-based sampling protocols predominate in the field. The invasiveness of a blood draw limits its utility to protected populations, including children and the elderly. Herein we describe a noninvasive means for sample collection (from fingerprints) paired with fast MS data-acquisition (MassIVE data set MSV000092742) and efficient data analysis via machine learning. Using both supervised and unsupervised classification, we demonstrate the usefulness of this method in determining whether a variable of interest imparts measurable change within the lipidomic data set. As a proof-of-concept, we show that the method is capable of distinguishing between the fingerprints of different individuals as well as between anatomical sebum collection regions. This noninvasive, high-throughput approach enables future lipidomic biomarker researchers to more easily include underrepresented, protected populations, such as children and the elderly, thus moving the field closer to definitive disease diagnoses that apply to all.

Diabetes status and cognitive function in middle-aged and older adults in the Canadian longitudinal study on aging

Objectives

Diabetes is recognized as a significant risk factor for cognitive impairment. However, this association has not been thoroughly examined using large-scale population-based datasets in the Canadian context. The objective of this study was to investigate the potential association between cognitive function and diabetes in a large population-based sample of middle-aged and older Canadians.

Methods

We utilized baseline data from the Canadian Longitudinal Study on Aging (N=30,097) to test our hypotheses, using five indicators of cognitive function (animal fluency, Stroop interference, reaction time, immediate and delayed memory recall). We conducted multivariate multivariable linear regression and subsequently performed tests for moderation analysis with lifestyle factors and health status.

Results

The analysis revealed that type 2 diabetes (T2DM) was associated with lower performance on most cognitive tasks, including those assessing executive function (b=0.60, 95% CI 0.31 to 0.90), reaction time (b=16.94, 95% CI 9.18 to 24.70), immediate memory recall (b=-0.10, 95% CI -0.18 to -0.02), and delayed memory recall (b=-0.12, 95% CI -0.21 to -0.02). However, no significant association was observed between other types of diabetes and cognitive performance. Moderation effects were largely null for T2DM, with the exception of alcohol intake for reaction time, and physical activity for animal fluency.

Conclusions

The study showed that individuals with T2DM exhibit poor performance on tasks that assess executive function, reaction time, and memory. Therefore, optimizing cognitive health among individuals with T2DM should be a priority in primary care. Additionally, further studies should examine this association using longitudinal data.

Association Between Triglycerides and Risk of Dementia in Community-Dwelling Older Adults: A Prospective Cohort Study

BACKGROUND AND OBJECTIVES

It has been suggested that higher triglyceride levels were associated with a lower risk of Alzheimer disease. This study aimed to examine the association of triglycerides with dementia and cognition change in community-dwelling older adults.

METHODS

This prospective longitudinal study used data from the Aspirin in Reducing Events in the Elderly (ASPREE) randomized trial of adults aged 65 years or older without dementia or previous cardiovascular events at enrollment. The main outcome was incident dementia. Other outcomes included changes in composite cognition and domain-specific cognition (global cognition, memory, language and executive function, and psychomotor speed). The association between baseline triglycerides and dementia risk was estimated using Cox proportional hazard models adjusting for relevant risk factors. Linear mixed models were used to investigate cognitive change. The analysis was repeated in a subcohort of participants with available APOE-ε4 genetic data with additional adjustment for APOE-ε4 carrier status and an external cohort (UK Biobank) with similar selection criteria applied.

RESULTS

This study included 18,294 ASPREE participants and 68,200 UK Biobank participants (mean age: 75.1 and 66.9 years; female: 56.3% and 52.7%; median [interquartile range] triglyceride: 106 [80-142] mg/dL and 139 [101-193] mg/dL), with dementia recorded in 823 and 2,778 individuals over a median follow-up of 6.4 and 12.5 years, respectively. Higher triglyceride levels were associated with lower dementia risk in the entire ASPREE cohort (hazard ratio [HR] with doubling of triglyceride: 0.82, 95% CI 0.72-0.94). Findings were similar in the subcohort of participants with APOE-ε4 genetic data (n = 13,976) and in the UK Biobank cohort (HR was 0.82 and 0.83, respectively, all p ≤ 0.01). Higher triglycerides were also associated with slower decline in composite cognition and memory over time (p ≤ 0.05).

DISCUSSION

Older adults with higher triglyceride levels within the normal to high-normal range had a lower dementia risk and slower cognitive decline over time compared with individuals with lower triglyceride levels. Higher triglyceride levels may be reflective of better overall health and/or lifestyle behaviors that would protect against dementia development. Future studies are warranted to investigate whether specific components within the total circulating pool of plasma triglycerides may promote better cognitive function, with the hope of informing the development of new preventive strategies.

Associations between circulating cardiovascular disease risk factors and cognitive performance in cognitively healthy older adults from the NuAge study

Introduction

Cardiovascular disease risk factors (CVRFs) contribute to the development of cognitive impairment and dementia.

Methods

This study examined the associations between circulating CVRF biomarkers and cognition in 386 cognitively healthy older adults (mean age = 78 ± 4 years, 53% females) selected from the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge). Memory, executive function, and processing speed were assessed at baseline and 2-year follow-up. CVRF biomarkers included total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides, glucose, insulin, high sensitivity C-reactive protein (hs-CRP), homocysteine, protein carbonyls, and cortisol. Linear mixed models were used to determine associations between individual CVRF biomarkers and cognition at both time points.

Results

HDL-C was most consistently associated with cognition with higher values related to better performance across several domains. Overall, stronger and more consistent relationships between CVRF biomarkers and cognition were observed in females relative to males.

Discussion

Findings suggest that increases in the majority of circulating CVRFs are not associated with worse cognition in cognitively healthy older adults.

Distinct effects of cholesterol profile components on amyloid and vascular burdens

BACKGROUND

Cholesterol plays important roles in β-amyloid (Aβ) metabolism and atherosclerosis. However, the relationships of plasma cholesterol levels with Aβ and cerebral small vessel disease (CSVD) burdens are not fully understood in Asians. Herein, we investigated the relationships between plasma cholesterol profile components and Aβ and CSVD burdens in a large, non-demented Korean cohort.

METHODS

We enrolled 1,175 non-demented participants (456 with unimpaired cognition [CU] and 719 with mild cognitive impairment [MCI]) aged ≥ 45 years who underwent Aβ PET at the Samsung Medical Center in Korea. We performed linear regression analyses with each cholesterol (low-density lipoprotein cholesterol [LDL-c], high-density lipoprotein cholesterol [HDL-c], and triglyceride) level as a predictor and each image marker (Aβ uptake on PET, white matter hyperintensity [WMH] volume, and hippocampal volume) as an outcome after controlling for potential confounders.

RESULTS

Increased LDL-c levels (β = 0.014 to 0.115, p = 0.013) were associated with greater Aβ uptake, independent of the APOE e4 allele genotype and lipid-lowering medication. Decreased HDL-c levels (β =  - 0.133 to - 0.006, p = 0.032) were predictive of higher WMH volumes. Increased LDL-c levels were also associated with decreased hippocampal volume (direct effect β =  - 0.053, p = 0.040), which was partially mediated by Aβ uptake (indirect effect β =  - 0.018, p = 0.006).

CONCLUSIONS

Our findings highlight that increased LDL-c and decreased HDL-c levels are important risk factors for Aβ and CSVD burdens, respectively. Furthermore, considering that plasma cholesterol profile components are potentially modified by diet, exercise, and pharmacological agents, our results provide evidence that regulating LDL-c and HDL-c levels is a potential strategy to prevent dementia.

Minimal amount of exercise prevents incident dementia in cognitively normal older adults with osteoarthritis: a retrospective longitudinal follow-up study

Robust evidence suggests that regular exercise, including walking more than 6000 steps, is effective for preventing dementia; however, such activity is less feasible in older people with osteoarthritis (OA) or other motor disabilities. Therefore, we aimed to test whether the minimal amount of exercise (MAE) could help prevent dementia in older adults with OA. A retrospective longitudinal study was performed and a non-demented cohort (≥ 50-years-old) of 242 people (155 [64.0%] non-converters and 87 [36.0%] converters) from three centers in Taiwan was analyzed with a mean follow-up of 3.1 (range 0.3-5.9) and 2.9 (range 0.5-6.0) years, respectively. MAE was defined as walking for approximately 15-30 min or 1500-3000 steps. Rate of MAE (0, 1-2, or ≥ 3) within one week were defined as MAE-no, MAE-weekly, or MAE-daily, respectively. The incidence rates of dementia were compared between groups. Multivariate logistic regression and Cox proportional hazards analyses were used to study the influence of MAE on dementia occurrence. Age, education, sex, activities of daily living, neuropsychiatric symptoms, cognition, multiple vascular risk factors, and related medications were adjusted. Compared to the MAE-no group, the odds ratios for the incidents of dementia were 0.48 and 0.19 in the MAE-weekly and MAE-daily groups, respectively. In addition, older age, poorer cognition, poorer ADL performance, and congestive heart failure increased the incidence of dementia. Daily and weekly MAE prevented dementia in older adults with OA. As such, an informative public health policy may help promote adequate exercise in at-risk groups.

Multi-domain prognostic models used in middle-aged adults without known cognitive impairment for predicting subsequent dementia

BACKGROUND

Dementia, a global health priority, has no current cure. Around 50 million people worldwide currently live with dementia, and this number is expected to treble by 2050. Some health conditions and lifestyle behaviours can increase or decrease the risk of dementia and are known as 'predictors'. Prognostic models combine such predictors to measure the risk of future dementia. Models that can accurately predict future dementia would help clinicians select high-risk adults in middle age and implement targeted risk reduction.

OBJECTIVES

Our primary objective was to identify multi-domain prognostic models used in middle-aged adults (aged 45 to 65 years) for predicting dementia or cognitive impairment. Eligible multi-domain prognostic models involved two or more of the modifiable dementia predictors identified in a 2020 Lancet Commission report and a 2019 World Health Organization (WHO) report (less education, hearing loss, traumatic brain injury, hypertension, excessive alcohol intake, obesity, smoking, depression, social isolation, physical inactivity, diabetes mellitus, air pollution, poor diet, and cognitive inactivity). Our secondary objectives were to summarise the prognostic models, to appraise their predictive accuracy (discrimination and calibration) as reported in the development and validation studies, and to identify the implications of using dementia prognostic models for the management of people at a higher risk for future dementia.

SEARCH METHODS

We searched MEDLINE, Embase, PsycINFO, CINAHL, and ISI Web of Science Core Collection from inception until 6 June 2022. We performed forwards and backwards citation tracking of included studies using the Web of Science platform.  SELECTION CRITERIA: We included development and validation studies of multi-domain prognostic models. The minimum eligible follow-up was five years. Our primary outcome was an incident clinical diagnosis of dementia based on validated diagnostic criteria, and our secondary outcome was dementia or cognitive impairment determined by any other method.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the references, extracted data using a template based on the CHecklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies (CHARMS), and assessed risk of bias and applicability of included studies using the Prediction model Risk Of Bias ASsessment Tool (PROBAST). We synthesised the C-statistics of models that had been externally validated in at least three comparable studies.  MAIN RESULTS: We identified 20 eligible studies; eight were development studies and 12 were validation studies. There were 14 unique prognostic models: seven models with validation studies and seven models with development-only studies. The models included a median of nine predictors (range 6 to 34); the median number of modifiable predictors was five (range 2 to 11). The most common modifiable predictors in externally validated models were diabetes, hypertension, smoking, physical activity, and obesity. In development-only models, the most common modifiable predictors were obesity, diabetes, hypertension, and smoking. No models included hearing loss or air pollution as predictors. Nineteen studies had a high risk of bias according to the PROBAST assessment, mainly because of inappropriate analysis methods, particularly lack of reported calibration measures. Applicability concerns were low for 12 studies, as their population, predictors, and outcomes were consistent with those of interest for this review. Applicability concerns were high for nine studies, as they lacked baseline cognitive screening or excluded an age group within the range of 45 to 65 years. Only one model, Cardiovascular Risk Factors, Ageing, and Dementia (CAIDE), had been externally validated in multiple studies, allowing for meta-analysis. The CAIDE model included eight predictors (four modifiable predictors): age, education, sex, systolic blood pressure, body mass index (BMI), total cholesterol, physical activity and APOEƐ4 status. Overall, our confidence in the prediction accuracy of CAIDE was very low; our main reasons for downgrading the certainty of the evidence were high risk of bias across all the studies, high concern of applicability, non-overlapping confidence intervals (CIs), and a high degree of heterogeneity. The summary C-statistic was 0.71 (95% CI 0.66 to 0.76; 3 studies; very low-certainty evidence) for the incident clinical diagnosis of dementia, and 0.67 (95% CI 0.61 to 0.73; 3 studies; very low-certainty evidence) for dementia or cognitive impairment based on cognitive scores. Meta-analysis of calibration measures was not possible, as few studies provided these data.

AUTHORS' CONCLUSIONS

We identified 14 unique multi-domain prognostic models used in middle-aged adults for predicting subsequent dementia. Diabetes, hypertension, obesity, and smoking were the most common modifiable risk factors used as predictors in the models. We performed meta-analyses of C-statistics for one model (CAIDE), but the summary values were unreliable. Owing to lack of data, we were unable to meta-analyse the calibration measures of CAIDE. This review highlights the need for further robust external validations of multi-domain prognostic models for predicting future risk of dementia in middle-aged adults.

Shift Work and Metabolic Syndrome Updates: A Systematic Review

Shift work can cause circadian cycles disturbances and misaligns the endogenous rhythms. The physiological variables are driven by the circadian system and, its misalignment, can impair the metabolic functions. Thus, the main objective of this study was to evaluate the metabolic alterations as a result of shift work and night work reported in articles published in the last 5 years, using the eligibility criteria both gender and indexed articles in English language. In order to execute this work, we perform a systematic review according to PRISMA guidelines and searched about Chronobiology Disorders and Night Work, both related to metabolism, in Medline, Lilacs, ScienceDirect and Cochrane. Cross-sectional, cohort and experimental studies with low risk of bias were included. We found a total of 132 articles, and, after the selection process, 16 articles remained to be analyzed. It was observed that shift work can cause circadian misalignment and, consequently, some metabolic parameters alterations such as an impaired glycemic control and insulin functioning, cortisol phase release, cholesterol fractions imbalance, changes in morphological indexes and melatonin secretion. There are some limitations, such as heterogenicity in used databases and the 5 years restriction period, because the effects of sleep disturbance may have been reported earlier. In conclusion, we suggest that shift work interferes with the sleep-wake cycle and eating patterns, which cause crucial physiological alterations that, together, can lead to metabolic syndrome.

Cardiovascular Risk Factors and Risk of Alzheimer Disease and Mortality: A Latent Class Approach

Background Cardiovascular risk factors co-occur with one another, and little is known about the extent of their clustering and risk of Alzheimer disease (AD). We identify groups of cardiovascular risk factors in cognitively normal individuals and investigate between-group differences in incident AD and death. Methods and Results Cognitively normal individuals were recruited from the National Alzheimer's Coordinator Center. A latent class analysis was conducted with hypertension, hypercholesterolemia, heart condition, stroke, smoking history, diabetes, and high body mass index. Between-group differences in the incidence of AD, mortality, and mortality-adjusted AD were investigated. This study included 12 412 cognitively normal individuals (average follow-up, 65 months). Three groups were identified: (1) low probabilities of cardiovascular risk factors (reference; N=5398 [43%]), (2) hypertension and hypercholesterolemia (vascular-dominant; N=5721 [46%]), and (3) hypertension, hypercholesterolemia, diabetes, and high body mass index (vascular-metabolic; N=1293 [10%]). Both vascular groups were significantly older, had more men, were slightly less educated, and were slightly more cognitively impaired than the reference group (all P<0.05). However, only the vascular-metabolic group had a significantly younger age of death compared with the reference group (84.3 versus 88.7 years, P<0.001). Only the vascular-dominant group had a greater incidence of AD (odds ratio [OR], 1.30; P<0.001) compared with the reference group. Mortality was greater in the vascular-dominant (OR, 3.26; P<0.001) and vascular-metabolic groups (OR, 1.84; P=0.02). Mortality-adjusted AD was greater in the vascular-dominant (OR, 1.54; P=0.02) and vascular-metabolic groups (OR, 1.46; P=0.04). Conclusions Three distinct cardiovascular risk factor groups were identified in cognitively normal elderly individuals. Only the vascular-dominant group was associated with a greater incidence of AD. Selective mortality may contribute to the attenuated association between the vascular-metabolic group and incident AD.

Effect of Obesity and High-Density Lipoprotein Concentration on the Pathological Characteristics of Alzheimer's Disease in High-Fat Diet-Fed Mice

The typical pathological features of Alzheimer's disease (AD) are the accumulation of amyloid plaques in the brain and reactivity of glial cells such as astrocytes and microglia. Clinically, the development of AD and obesity are known to be correlated. In this study, we analyzed the changes in AD pathological characteristics in 5XFAD mice after obesity induction through a high-fat diet (HFD). Surprisingly, high-density lipoprotein and apolipoprotein AI (APOA-I) serum levels were increased without low-density lipoprotein alteration in both HFD groups. The reactivity of astrocytes and microglia in the dentate gyrus of the hippocampus and fornix of the hypothalamus in 5XFAD mice was decreased in the transgenic (TG)-HFD high group. Finally, the accumulation of amyloid plaques in the dentate gyrus region of the hippocampus was also significantly decreased in the TG-HFD high group. These results suggest that increased high-density lipoprotein level, especially with increased APOA-I serum level, alleviates the pathological features of AD and could be a new potential therapeutic strategy for AD treatment.

Risk Prediction Performance of the Thai Cardiovascular Risk Score for Mild Cognitive Impairment in Adults with Metabolic Risk Factors in Thailand

Individuals with metabolic risks are at high risk of cognitive impairment. We aimed to investigate whether the Thai Cardiovascular Risk (TCVR) score can be used to predict mild cognitive impairment (MCI) in Thai adults with metabolic risks. The study was conducted using secondary data of patients with metabolic risks from Maharaj Nakorn Chiang Mai Hospital. MCI was indicated by an MoCA score of less than 25. Six different TCVR models were used with various combinations of ten different variables for predicting the risk of MCI. The area under the receiver operator characteristic curve (AuROC) and Hosmer–Lemeshow goodness of fit tests were used for determining discriminative performance and model calibration. The sensitivity of the discriminative performance was further evaluated by stratifying by age and gender. From a total of 421 participants, 348 participants had MCI. All six TCVR models showed a similar AuROC, varying between 0.58 and 0.61. The anthropometric-based model showed the best risk prediction performance in the older age group (AuROC 0.69). The laboratory-based model provided the highest discriminative performance for the younger age group (AuROC 0.60). There is potential for the development of an MCI risk model based on values from routine cardiovascular risk assessments among patients with metabolic risks.

Association of Metabolic Syndrome With Incident Dementia: Role of Number and Age at Measurement of Components in a 28-Year Follow-up of the Whitehall II Cohort Study

OBJECTIVE

Previous research suggests an inconsistent association between Metabolic syndrome (MetS) and incident dementia. We examined the role of number of MetS components and age at their assessment for incident dementia.

RESEARCH DESIGN AND METHODS

MetS components (fasting glucose, triglycerides, waist circumference, blood pressure, and HDL cholesterol) on 7,265, 6,660, and 3,608 participants at <60, 60 to <70, and ≥70 years of age were used to examine associations with incident dementia using cause-specific Cox regression.

RESULTS

Analyses of MetS measured at <60, 60 to <70, and ≥70 years involved 393 (5.4%), 497 (7.5%), and 284 (7.9%) dementia cases over a median follow-up of 20.8, 10.4, and 4.2 years, respectively. Every additional MetS component before 60 (hazard ratio [HR] 1.13 [95% CI 1.05, 1.23]) and 60 to <70 (HR 1.08 [95% CI 1.00, 1.16]) but not ≥70 years (HR 1.04 [95% CI 0.96, 1.13]) was associated with higher dementia risk. MetS defined conventionally (≥3 components) before 60 years (HR 1.23 [95% CI 0.96, 1.57]), between 60 and 70 years (HR 1.14 [95% CI 0.91, 1.42]), or >70 years of age (HR 1.10 [95% CI 0.86, 1.40]) was not associated with incident dementia. Multistate models showed higher risk of dementia in those with ≥1 (HR 1.99 [95% CI 1.08, 3.66]) and ≥2 MetS components (HR 1.69 [95% CI 1.12, 2.56]) before 60 years of age, even when they remained free of cardiovascular disease over the follow-up.

CONCLUSIONS

Risk of incident dementia increases with every additional MetS component present in midlife rather than after accumulation of three components; only part of this risk is mediated by cardiovascular disease.

LDL cholesterol is associated with higher AD neuropathology burden independent of APOE

OBJECTIVE

APOE is a strong risk factor for Alzheimer's disease (AD) and associated with higher low-density lipoprotein cholesterol (LDL-C) levels. Moreover, LDL-C is associated with the development of clinically ascertained AD; however, whether this association is present with the underlying neuropathological manifestations of AD or whether it is independent of the effect of APOE is unknown and is the focus of this paper.

METHODS

Individuals in the Religious Orders Study/Memory and Ageing Project cohorts with longitudinal measures of blood lipids and detailed autopsies were studied. We modelled the relationship between blood lipids and 12 age-related brain pathologies using a linear mixed model adjusted for potential confounding factors and stratified by APOE genotype with overall significance determined by meta-analysis. Blood lipids considered were LDL-C, high-density lipoprotein cholesterol and triglycerides. Brain pathologies included AD pathology measured by silver staining (Braak stage, a modified Consortium to Establish a Registry for Alzheimer's Disease [CERAD] score and global AD pathology) and immunohistochemistry (beta-amyloid and neurofibrillary tangles) as well as cerebral microinfarct, cerebral macroinfarct, cerebral amyloid angiopathy, cerebral atherosclerosis, hippocampal sclerosis, TDP-43 cytoplasmic inclusions and Lewy bodies.

RESULTS

559 participants (69.1% female) had complete data for analysis. They were followed for a median of 7 years and a median of 3 years prior to dementia onset. LDL-C was associated with all measures of AD neuropathology (neurofibrillary tangles, beta-amyloid, Braak stage, modified CERAD score and global AD pathology) and cerebral amyloid angiopathy independent of APOE after adjusting for age, sex, cholesterol-lowering medication use, body mass index, smoking and education at false discovery rate (FDR) p-value <0.05.

CONCLUSIONS

These findings implicate LDL-C in the pathophysiology of AD independent of APOE and suggest LDL-C is a modifiable risk factor for AD.

Body mass index in early adulthood and dementia in late life: Findings from a pooled cohort

INTRODUCTION

To examine the independent association of body mass index (BMI) in early adulthood with dementia incidence among men and women.

METHODS

We studied 5104 older adults from the Cardiovascular Health Study (CHS) and the Health, Aging, and Body Composition (Health ABC) study. We imputed early adulthood and midlife BMI using a pooled parent cohort with complete adult lifespan coverage and previously established methods. Dementia was ascertained using criteria such as neuropsychological test battery, medical records, and dementia-related drug use. Pooled logistic regression (PLR) models were used.

RESULTS

Compared to women with normal BMI in early adulthood, the odds of dementia were higher among both overweight (odds ratio [OR] = 1.8; 95% confidence interval [CI] = 1.31 to 2.54) and obese (OR = 2.45; 95% CI = 1.47 to 4.06) women, independent of mid- and late-life BMI. Similar relationship was observed in men.

CONCLUSIONS

With the growing obesity epidemic among US adults, efforts aimed at reducing dementia may need to begin obesity prevention and treatment early in the life course.

Variability in Cardiometabolic and Inflammatory Parameters and Cognitive Decline

INTRODUCTION

The relationship between variability in cardiometabolic and inflammatory parameters and cognitive changes is unknown. This study investigates the association of visit-to-visit variability in BMI, mean arterial pressure, total cholesterol, triglycerides, HbA1c, high-sensitivity C-reactive protein, ferritin, and fibrinogen with cognitive decline.

METHODS

This population-based cohort study included 2,260 individuals (mean age=63.0 [SD=7.5] years) free of cognitive diseases who underwent ≥3 clinical measurements from 2004 to 2019. Variability was expressed as variability independent of the mean across visits. Participants were divided on the basis of quartiles of variability score, a scoring system generated to explore the composite effect of parameter variability (range=0-24), where 0 points were assigned for Quartile 1, 1 point was assigned for Quartile 2, 2 points were assigned for Quartile 3, and 3 points were assigned for Quartile 4, each for the variability of 8 parameters measured as variability independent of the mean. Linear mixed models evaluated the longitudinal associations with cognitive decline in memory and verbal fluency. All analyses were conducted in 2020-2021.

RESULTS

Higher BMI, mean arterial pressure, total cholesterol, HbA1c, and ferritin variability were linearly associated with cognitive decline irrespective of their mean values. In addition, participants in the highest quartile of variability score had a significantly worse cognitive decline rate in memory (-0.0224 points/year, 95% CI= -0.0319, -0.0129) and verbal fluency (-0.0088 points/year, 95% CI= -0.0168, -0.0008) than those in the lowest quartile.

CONCLUSIONS

A higher variability in cardiometabolic and inflammatory parameters was significantly associated with cognitive decline. Stabilizing these parameters may serve as a target to preserve cognitive functioning.

Relationship between Central Obesity and the incidence of Cognitive Impairment and Dementia from Cohort Studies Involving 5,060,687 Participants

Central obesity, measured by the waist circumference (WC) or waist-to-hip ratio, has been linked with metabolic dysfunction and structural abnormalities in the brain, two risk factors for cognitive impairment and dementia. The current analysis was performed to understand the influence of central obesity on the incidence of cognitive impairment and dementia. It included 21 studies involving 5,060,687 participants and showed that a high WC was associated with a greater risk of cognitive impairment and dementia (HR = 1.10, 95 % CI: 1.05-1.15), compared with a low WC. Sub-group analysis showed that a high WC increased the likelihood of developing cognitive impairment and dementia in individuals older than 65 years of age (HR = 1.13, 95 % CI: 1.08-1.19), whereas no association was observed in individuals younger than 65 years of age (HR = 1.04, 95 % CI: 0.93-1.16). Furthermore, dose-response meta-analysis confirmed that a high WC was a risk factor for cognitive impairment and dementia. In conclusion, central obesity, as measured by WC, was associated with a risk of cognitive impairment and dementia.

Effects of Dietary Food Components on Cognitive Functions in Older Adults

Population aging has recently been an important issue as the number of elderly people is growing worldwide every year, and the extension of social security costs is financially costly. The increase in the number of elderly people with cognitive decline is a serious problem related to the aging of populations. Therefore, it is necessary to consider not only physical care but also cognitive patterns in the future care of older adults. Since food contains a variety of bioactive substances, dietary patterns may help improve age-related cognitive decline. However, the relationship between cognitive function and individual food components remains ambiguous as no clear efficacy or mechanism has been confirmed. Against this background, this review summarizes previous reports on the biological process of cognitive decline in the elderly and the relationship between individual compounds in foods and cognitive function, as well as the role of individual components of food in cognitive function, in the following order: lipids, carotenoids, vitamins, phenolic compounds, amino acids, peptides, and proteins. Based on the research presented in this review, a proper diet that preserves cognitive function has the potential to improve age-related cognitive decline, Alzheimer's disease, and Parkinson's disease. Hopefully, this review will help to trigger the development of new foods and technologies that improve aging and cognitive functions and extend the healthy life span.

The Role of High Triglycerides Level in Predicting Cognitive Impairment: A Review of Current Evidence

The burden of cognitive disorders is huge and still growing, however the etiology and the degree of cognitive impairment vary considerably. Neurodegenerative and vascular mechanisms were most frequently assessed in patients with dementia. Recent studies have shown the possible involvement of triglycerides levels in cognitive function through putative mechanisms such as brain blood barrier dysfunction or amyloid metabolism imbalance, but not all research in the field found this association. Several clinical studies evaluated the relationship between different forms of cognitive decline and levels of serum triglycerides, independent of other cardiovascular risk factors. This review focuses on the role of triglycerides in cognitive decline, cerebral amyloidosis and vascular impairment. Considering that the management of hypertriglyceridemia benefits from lifestyle modification, diet, and specific drug therapy, future studies are requested to appraise the triglycerides-cognitive impairment relationship.

Plasma lipidome is dysregulated in Alzheimer's disease and is associated with disease risk genes

Lipidomics research could provide insights of pathobiological mechanisms in Alzheimer's disease. This study explores a battery of plasma lipids that can differentiate Alzheimer's disease (AD) patients from healthy controls and determines whether lipid profiles correlate with genetic risk for AD. AD plasma samples were collected from the Sydney Memory and Ageing Study (MAS) Sydney, Australia (aged range 75-97 years; 51.2% male). Untargeted lipidomics analysis was performed by liquid chromatography coupled-mass spectrometry (LC-MS/MS). We found that several lipid species from nine lipid classes, particularly sphingomyelins (SMs), cholesterol esters (ChEs), phosphatidylcholines (PCs), phosphatidylethanolamines (PIs), phosphatidylinositols (PIs), and triglycerides (TGs) are dysregulated in AD patients and may help discriminate them from healthy controls. However, when the lipid species were grouped together into lipid subgroups, only the DG group was significantly higher in AD. ChEs, SMs, and TGs resulted in good classification accuracy using the Glmnet algorithm (elastic net penalization for the generalized linear model [glm]) with more than 80% AUC. In general, group lipids and the lipid subclasses LPC and PE had less classification accuracy compared to the other subclasses. We also found significant increases in SMs, PIs, and the LPE/PE ratio in human U251 astroglioma cell lines exposed to pathophysiological concentrations of oligomeric Aβ₄₂. This suggests that oligomeric Aβ₄₂ plays a contributory, if not causal role, in mediating changes in lipid profiles in AD that can be detected in the periphery. In addition, we evaluated the association of plasma lipid profiles with AD-related single nucleotide polymorphisms (SNPs) and polygenic risk scores (PRS) of AD. We found that FERMT2 and MS4A6A showed a significantly differential association with lipids in all lipid classes across disease and control groups. ABCA7 had a differential association with more than half of the DG lipids (52.63%) and PI lipids (57.14%), respectively. Additionally, 43.4% of lipids in the SM class were differentially associated with CLU. More than 30% of lipids in ChE, PE, and TG classes had differential associations with separate genes (ChE-PICALM, SLC24A4, and SORL1; PE-CLU and CR1; TG-BINI) between AD and control group. These data may provide renewed insights into the pathobiology of AD and the feasibility of identifying individuals with greater AD risk.

Cumulative Exposure to Metabolic Syndrome Components and the Risk of Dementia: A Nationwide Population-Based Study

BACKGROUND

Metabolic disturbances are modifiable risk factors for dementia. Because the status of metabolic syndrome (MetS) and its components changes over time, we aimed to investigate the association of the cumulative exposure to MetS and its components with the risk of dementia.

METHODS

Adults (n=1,492,776; ≥45-years-old) who received health examinations for 4 consecutive years were identified from a nationwide population-based cohort in Korea. Two exposure-weighted scores were calculated: cumulative number of MetS diagnoses (MetS exposure score, range of 0 to 4) and the composite of its five components (MetS component exposure score, range of 0 to 20). Hazard ratio (HR) and 95% confidence interval (CI) values for dementia were analyzed using the multivariable Cox proportional-hazards model.

RESULTS

Overall, 47.1% of subjects were diagnosed with MetS at least once, and 11.5% had persistent MetS. During the mean 5.2 years of follow-up, there were 7,341 cases (0.5%) of incident dementia. There was a stepwise increase in the risk of all-cause dementia, Alzheimer's disease, and vascular dementia with increasing MetS exposure score and MetS component exposure score (each P for trend <0.0001). The HR of all-cause dementia was 2.62 (95% CI, 1.87 to 3.68) in subjects with a MetS component exposure score of 20 compared with those with a score of 0. People fulfilling only one MetS component out of 20 already had an approximately 40% increased risk of all-cause dementia and Alzheimer's disease.

CONCLUSION

More cumulative exposure to metabolic disturbances was associated with a higher risk of dementia. Of note, even minimal exposure to MetS components had a significant effect on the risk of dementia.

The sex-specific effect of the apolipoprotein E allele and methylenetetrahydrofolate reductase gene polymorphism on the biochemical, anatomical, and cognitive profiles of patients clinically diagnosed with probable Alzheimer's disease

OBJECTIVES

We aimed to evaluate the sex-specific effect of apolipoprotein E (APOE) alleles and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism on the biochemical, anatomical, and cognitive profiles of Alzheimer's disease (AD) patients.

METHODS

The patient (followed-up for at least 2 years) medical records, which comprised of data on plasma homocysteine and folate levels, lipid profile, HbA1c, MTHFR C677T genotype, APOE allele type, mini-mental state examination (MMSE) and clinical dementia rating (CDR) scores, and brain scans, were retrospectively analyzed. Two trained neurologists scored the white matter lesions (Fazekas scale), medial temporal lobe atrophy (MTA), and microbleeds using brain magnetic resonance imaging scans.

RESULTS

This study included 574 patients clinically diagnosed with probable AD (average age, 73.2 years; mean MMSE score, 10.05). The effect of sex on all parameters was evaluated. The triglyceride (TG) and homocysteine levels and the MTA and Fazekas scores were higher in female APOE-ε4/ε4 carriers than in women without APOE-ε4. The TG and homocysteine levels were lower in men with the MTHFR CC allele than in those with the MTHFR TT allele. In contrast, MTHFR polymorphism and APOE-ε4 alleles were not significantly correlated with anatomical lesions and rate of decline in the MMSE and CDR scores.

CONCLUSIONS

We demonstrated the sex-specific effect of the APOE allele and MTHFR polymorphism on the serological and anatomical biomarkers in AD patients. The APOE allele and MTHFR mutations did not directly affect cognitive progression, but differentially affected other biochemical factors, between the sexes. These findings will aid in devising novel preventive and therapeutic strategies.

Brain insulin, insulin-like growth factor 1 and glucagon-like peptide 1 signalling in Alzheimer's disease

Although the brain was once considered an insulin-independent organ, insulin signalling is now recognised as being central to neuronal health and to the function of synapses and brain circuits. Defective brain insulin signalling, as well as related signalling by insulin-like growth factor 1 (IGF-1), is associated with neurological disorders, including Alzheimer's disease, suggesting that cognitive impairment could be related to a state of brain insulin resistance. Here, I briefly review key epidemiological/clinical evidence of the association between diabetes, cognitive decline and AD, as well as findings of reduced components of insulin signalling in AD brains, which led to the initial suggestion that AD could be a type of brain diabetes. Particular attention is given to recent studies illuminating mechanisms leading to neuronal insulin resistance as a key driver of cognitive impairment in AD. Evidence of impaired IGF-1 signalling in AD is also examined. Finally, we discuss potentials and possible limitations of recent and on-going therapeutic approaches based on our increased understanding of the roles of brain signalling by insulin, IGF-1 and glucagon-like peptide 1 in AD.

Every-other day fasting prevents memory impairment induced by high fat-diet: Role of oxidative stress

Imbalance of diet consumption results in memory and learning deterioration. High-fat diet (HFD) causes neuronal damage and eventually cognitive impairment, which can be related to increasing oxidative stress in the brain. Using the every other day fasting (EODF) paradigm, as a method of dietary restriction is thought to provide protection of learning and memory in several experimental studies. In the current work, the preventive effect of EODF paradigm on memory impairment-induced by HFD was investigated. Adult male Wistar rats were fed with HFD using the EODF paradigm for six weeks. At the end of these six weeks, and while the previous treatment were continued, rats were examined for learning and memory (both the short-term and the long-term memory) using the radial arm water maze (RAWM). Oxidative stress in the brain, namely in the hippocampus was also assessed. Chronic administration of HFD induced impairment in both, short- and long- term memory that was prevented using EODF paradigm. Furthermore, EODF prevented HFD-induced decrease in the activities of the antioxidant enzymes, SOD and catalase along with reduction of glutathione (GSH) level and the ratio of reduced glutathione/oxidized glutathione (GSH/GSSG ratio). The EODF also inhibited rise in oxidized glutathione (GSSG) and thiobarbituric acid reactive substances (TBARS) seen with HFD. In conclusion, EODF ameliorated oxidative stress and memory impairment induced by chronic HFD. This probably, can be explained by the ability of EODF to normalize mechanisms involved in oxidative stress in the hippocampus.

Associations between metabolic syndrome and type of dementia: analysis based on the National Health Insurance Service database of Gangwon province in South Korea

BACKGROUND

Metabolic syndrome is a cluster of conditions that occur together, increasing the risk of cardiovascular disease. However, the relationship between metabolic syndrome and dementia has remained controversial. Using nationwide population cohort data, we investigated the association between metabolic syndrome and dementia, according to the dementia type.

METHODS

We analyzed data of 84,144 individuals, in the aged group of more than 60 years, between January 1, 2009, to December 31, 2009, at Gangwon province by using the information of the (Korean) National Health Insurance Service. After eight years of gap, in 2017, we investigated the relationship between metabolic syndrome and dementia. We classified Dementia either as dementia of the Alzheimer type (AD) or vascular dementia (VD). AD and VD were defined as per the criteria of International Classification of Disease, Tenth Revision, Clinical Modification codes. Multiple logistic regression analyses examined the associations between metabolic syndrome or five metabolic syndrome components and dementia. Analyses included factors like age, sex, smoking, alcohol, physical inactivity, previous stroke, and previous cardiac disease.

RESULTS

Metabolic syndrome was associated with AD (OR = 11.48, 95% CI 9.03-14.59), not with VD. Each of five components of metabolic syndrome were also associated with AD. (high serum triglycerides: OR = 1.87, 95% CI 1.60-2.19; high blood pressure: OR = 1.85, 95% CI 1.55-2.21; high glucose: OR = 1.77, 95% CI 1.52-2.06; abdominal obesity: OR = 1.88, 95% CI 1.57-2.25; low serum high-density lipoprotein cholesterol: OR = 1.91, 95% CI 1.63-2.24) However, among components of metabolic syndrome, only the high glucose level was associated with VD. (OR = 1.26, 95% CI 1.01-1.56) body mass index (BMI), fasting glucose, and smoking were also associated with AD. (BMI: OR = 0.951, 95% CI 0.927-0.975; fasting glucose: OR = 1.003, 95% CI 1.001-1.005; smoking: OR = 1.020, 95% CI 1.003-1.039) A history of the previous stroke was associated with both AD and VD. (AD: OR = 1.827, 95% CI 1.263-2.644; VD: OR 2.775, 95% CI 1.747-4.406) CONCLUSIONS: Metabolic syndrome was associated with AD but not with VD. Patients with metabolic syndrome had an 11.48 times more likeliness to develop AD compared to those without metabolic syndrome. VD was associated only with several risk factors that could affect the vascular state rather than a metabolic syndrome. We suggested that the associations between metabolic syndrome and dementia would vary depending on the type of dementia.

Brain arteriolosclerosis

Brain arteriolosclerosis (B-ASC), characterized by pathologic arteriolar wall thickening, is a common finding at autopsy in aged persons and is associated with cognitive impairment. Hypertension and diabetes are widely recognized as risk factors for B-ASC. Recent research indicates other and more complex risk factors and pathogenetic mechanisms. Here, we describe aspects of the unique architecture of brain arterioles, histomorphologic features of B-ASC, relevant neuroimaging findings, epidemiology and association with aging, established genetic risk factors, and the co-occurrence of B-ASC with other neuropathologic conditions such as Alzheimer's disease and limbic-predominant age-related TDP-43 encephalopathy (LATE). There may also be complex physiologic interactions between metabolic syndrome (e.g., hypertension and inflammation) and brain arteriolar pathology. Although there is no universally applied diagnostic methodology, several classification schemes and neuroimaging techniques are used to diagnose and categorize cerebral small vessel disease pathologies that include B-ASC, microinfarcts, microbleeds, lacunar infarcts, and cerebral amyloid angiopathy (CAA). In clinical-pathologic studies that factored in comorbid diseases, B-ASC was independently associated with impairments of global cognition, episodic memory, working memory, and perceptual speed, and has been linked to autonomic dysfunction and motor symptoms including parkinsonism. We conclude by discussing critical knowledge gaps related to B-ASC and suggest that there are probably subcategories of B-ASC that differ in pathogenesis. Observed in over 80% of autopsied individuals beyond 80 years of age, B-ASC is a complex and under-studied contributor to neurologic disability.

Hypertension and Hypercholesterolemia Modify Dementia Risk in Relation to APOEɛ4 Status

BACKGROUND

There is significant interest in understanding the role of modifiable vascular risk factors contributing to dementia risk across age groups.

OBJECTIVE

Risk of dementia onset was assessed in relation to vascular risk factors of hypertension and hypercholesterolemia among cognitively normal APOEɛ4 carriers and non-carriers.

METHODS

In a sample of prospectively characterized longitudinal cohort from the National Alzheimer's Coordinating Center database, 9,349 participants met criteria for normal cognition at baseline, had a CDR-Global (CDR-G) score of zero, and had concomitant data on APOEɛ4 status and medical co-morbidities including histories of hypertension and hypercholesterolemia. Multivariable Cox proportional hazards models adjusted for well-known potential confounders were used to compare dementia onset among APOEɛ4 carriers and non-carriers by young (≤65 years) and old (> 65 year) age groups.

RESULTS

519 participants converted to dementia within an average follow up of 5.97 years. Among older APOEɛ4 carriers, hypercholesterolemia was related to lower risk of dementia (HR (95% CI), 0.68 (0.49-0.94), p = 0.02). Among older APOEɛ4 non-carriers, hypertension was related to higher risk of dementia (HR (95% CI), 1.44 (1.13-1.82), p = 0.003). These results were corroborated among a subset with autopsy data characterizing underlying neuropathology. Among younger participants, vascular risk factors did not impact dementia risk, likely from a lower frequency of vascular and Alzheimer's as etiologies of dementia among this cohort.

CONCLUSION

A history of hypercholesterolemia related to a lower risk of dementia among older APOEɛ4 carriers, while hypertension related to a higher risk of dementia among older APOEɛ4 non-carriers.

Date seeds alleviate behavioural and neuronal complications of metabolic syndrome in rats

Unhealthy dietary habits can play a crucial role in metabolic damages, promoting alteration of neural functions through the lifespan. Recently, dietary change has been perceived as the first line intervention in prevention and/or treatment of metabolic damages and related diseases. In this context, our study was designed to assess the eventual therapeutic effect of date seeds administration on memory and learning and on neuronal markers in a rat Metabolic Syndrome model. For this purpose, 32 adult male Wistar rats were fed with standard diet or high-fat high-sugar diet during ten weeks. After this, 16 rats were sacrified and the remaining rats received an oral administration of 300 mg of date seeds/kg of body weight during four supplementary weeks. Before sacrifice, we evaluate cognitive performances by the Barnes maze test. Afterwards, neuronal, astrocytic, microtubular and oxidative markers were investigated by immunoblotting methods. In Metabolic syndrome rats, results showed impairment of spatial memory and histological alterations. We identified neuronal damages in hippocampus, marked by a decrease of NeuN and an increase of GFAP and pTau396. Finally, we recorded an increase in protein oxidation and lipid peroxidation, respectively identified by an up-regulation of protein carbonyls and 4-HNe. Interestingly, date seeds administration improved these behavioural, histological, neuronal and oxidative damages highlighting the neuroprotective effect of this natural compound. Liquid Chromatography-Mass Spectrometry (LC-MS) identified, in date seeds, protocatechuic acid, caffeoylshikimic acid and vanillic acid, that could potentially prevent the progression of neurodegenerative diseases, acting through their antioxidant properties.

Metabolic dysfunction modifies the influence of traffic-related air pollution and noise exposure on late-life dementia and cognitive impairment: A cohort study of older Mexican-Americans

Supplemental Digital Content is available in the text.

Cognitive impairment has been linked to traffic-related air pollution and noise exposure as well as to metabolic syndrome or some of its individual components. Here, we investigate whether the presence of metabolic dysfunction modifies associations between air pollution or noise exposures and incident dementia or cognitive impairment without dementia (CIND).

Association of mid-life serum lipid levels with late-life brain volumes: The atherosclerosis risk in communities neurocognitive study (ARICNCS)

BACKGROUND

Limited information exists regarding the association between midlife lipid levels and late-life total and regional brain volumes.

METHODS

We studied 1872 participants in the longitudinal community-based Atherosclerosis Risk in Communities Neurocognitive Study. Serum lipid levels were measured in 1987-1989 (mean age, 53 ± 5 years). Participants underwent 3T brain MRI scans in 2011-2013. Brain volumes were measured using FreeSurfer image analysis software. Linear regression models were used to assess the associations between serum lipids and brain volumes modeled in standard deviation (SD) units, adjusting for potential confounders.

RESULTS

In adjusted analyses, one SD higher low-density lipoprotein cholesterol (LDL) levels were associated with larger total brain volumes (β 0.033, 95% CI 0.006-0.060) as well as larger volumes of the temporal (β 0.038, 95% CI 0.003-0.074) and parietal lobes (β 0.044, 95% CI 0.009-0.07) and Alzheimer disease-related region (β 0.048, 95% CI 0.048-0.085). Higher triglyceride levels were associated with smaller total brain volumes (β -0.033, 95% CI -0.060, -0.007). The associations between LDL levels and brain volumes were modified by age (P for interaction <0.001), with higher LDL levels associated with larger total and regional brain volumes only among adults >53 years at baseline, and were attenuated after application of weights to account for informative attrition, although associations with the parietal and Alzheimer's disease-related region remained significant. High-density lipoprotein cholesterol was not associated with brain volumes.

CONCLUSION

Higher LDL levels in late midlife were associated with larger brain volumes later in life, while higher triglyceride levels were associated with smaller brain volumes. These associations were driven by adults >53 years at baseline.

The Association between HbA1c Levels, Olfactory Memory and Cognition in Normal, Pre-Diabetic and Diabetic Persons

BACKGROUND AND AIM

Recent data have shown that olfactory dysfunction is strongly related to Alzheimer's Disease (AD) that is often preceded by olfactory deficits suggesting that olfactory dysfunction might represent an early indicator of future cognitive in prediabetes.

METHODS

We have applied to a group of normal (n=15), prediabetic (n=16) and type 2 diabetic outpatients (n=15) olfactory testing, 1.5-T MRI scanner and detailed cognitive evaluation including the standard Mini-Mental State Examination (MMSE) form, Short Blessed Test (SBT), Letter Fluency Test (LFT) and the category fluency test with animal, Fruit and Vegetable Naming (CFT).

RESULTS

We have shown that Odour Threshold (OT), Discrimination (OD), and Identification (OI) scores and most cognitive test results were significantly different in the prediabetes and diabetes group compared to those in the control group. OD and OT were significantly different between the prediabetes and diabetes group, although the cognitive test results were only significantly different in the prediabetes and diabetes group compared to those in the control group. In evaluating the association between OI, OT, OD scores and specific cognitive tests, we have found, that impaired olfactory identification was the only parameter that correlated significantly with the SBT both in the pre-diabetes and diabetes group. Although spot glucose values were only correlated with OT, HbA1c levels were correlated with OT, OD, and OI, as well as results of the letter fluency test suggesting that HbA1c levels rather than the spot glucose values play a critical role in specific cognitive dysfunction.

CONCLUSION

To the best of our knowledge, this is the first prospective study to demonstrate a strong association between olfactory dysfunction and specific memory impairment in a population with prediabetes and diabetes suggesting that impaired olfactory identification might play an important role as a specific predictor of memory decline.

Blood Lipids and Cognitive Performance of Aging Polish Adults: A Case-Control Study Based on the PolSenior Project

Background: The demand for effective strategies for maintaining cognitive capableness and establishing early dementia diagnosis has been tremendous, especially in the context of population aging. However, studies on the elderly population and neurocognitive impairment had provided ambiguous results throughout, while potential blood biomarkers of cognitive decline are yet to be clearly understood.

Objectives: The present study is aimed at assessing the relationship between blood lipids—especially in the context of their usefulness as biomarkers of an early cognitive decline—and cognitive functioning of aging adults.

Materials and Methods: The study sample consisted of 230 participants—(109 women, 121 men) aged 65+ years. Plasma 24(S)-hydroxycholesterol [24(S)-OHC], serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL), and low-density lipoprotein cholesterol (LDL) were assessed. The analyses were conducted in three groups of cognitive performance: cognitively normal, mild cognitive impairment (MCI), and mild dementia, of which the subjects were divided with the Mini-Mental State Examination (MMSE).

Results: No significant differences in 24(S)-OHC plasma concentrations for different levels of cognitive performance were found. Significant differences were found in serum TC (p = 0.026) and LDL (p = 0.007) concentrations for different levels of cognitive performance. Concentrations of both parameters were highest in the MCI group and lowest in mild dementia and cognitive norm, respectively. No significant differences between serum HDL concentrations and cognitive performance were found.

Conclusions: To fully assess the potential of research on blood lipids in regards to a cognitive decline, cross-sectional or epidemiological studies aimed at further exploring blood lipid roles in both the early and advanced MCI and dementia, are needed.

Metabolic Syndrome and Cognitive Trajectories in the Framingham Offspring Study

Metabolic syndrome (MetS) has been linked to increased risk of developing cognitive impairment and dementia including Alzheimer's disease. It remains unclear whether and at what stage in the adult lifespan MetS and its components begin to alter the trajectory of cognitive performance. In the present study, 2,892 Framingham Offspring participants completed health assessments every four years since 1971 and underwent repeat neuropsychological testing from 1999 to 2014. We estimated the associations of levels and changes in cognitive trajectories with hazard of MetS using a joint growth/survival model. All models were adjusted for baseline age, sex, education, and smoking status. Findings showed that both mid-life and late-life MetS were associated with lower level of cognitive functioning but not cognitive trajectories. Associations were strongest among those who were nondemented and apolipoprotein (APOE) ɛ4 noncarriers. In addition, individuals with the most rapid cognitive decline were more likely to have MetS. The pattern of results showed that associations between MetS and cognition varied, depending upon whether the sample was stratified by genetic and cognitive status and whether we considered cognitive performance as a continuous variable or examined categorical groupings. Given that mid-life MetS was associated with poorer cognition at age 55, cognitive changes may occur early during the MetS process. Our findings suggest that those with MetS are at greater risk of dementia given their lower level of cognitive functioning and also suggest that MetS may be a risk factor for decline in the absence of known risk factors including the APOEɛ4 allele.

Association of Circulating Cholesterol Level with Cognitive Function and Mild Cognitive Impairment in the Elderly: A Community-based Population Study

Background:

The present study was designed to examine the association of circulating cholesterol with cognitive function in non-demented community aging adults.

Methods:

This was a cross-sectional study including 1754 Chinese adults aged 55-80 years. The association between serum cholesterol levels and cognitive function was examined. Participants were categorized into four groups according to the quartile of circulating TC (total cholesterol), High Density Lipoprotein Cholesterol (HDL-c), Low Density Lipoprotein Cholesterol (LDL-c) levels and HDLc/ LDL-c ratio. The difference in cognitive performance among the groups was compared. Logistic regression model was used to determine the association of circulating cholesterol level with the risk of Mild Cognitive Impairment (MCI).

Results:

Mild increase of serum LDL-c level correlated with better visual and executive, language, memory and delayed recall abilities. Higher circulating TC and HDL-c levels were found to be associated with poorer cognitive function, especially in aging female subjects. Higher circulating TC, HDL-c and HDL/LDL ratio indicated an increased risk of MCI, especially in female subjects.

Conclusion:

Slight increase in circulating LDL-c level might benefit cognitive function in aging adults. However, higher circulating TC and HDL-c levels might indicate a decline of cognitive function, especially in aging female subjects.

Association of mild cognitive impairment and metabolic syndrome in patients with hypertension

AIM

The aim of this study was to evaluate the prevalence of mild cognitive impairment (MCI) in patients with hypertension and to evaluate the association of MCI with metabolic syndrome (MetS).

METHODOLOGY

186 subjects with hypertension were evaluated on Montreal Cognitive Assessment (MoCA) and Patient Health Questionnaire (PHQ-9) for cognitive decline and depression, respectively and MetS was diagnosed as per the Consensus definition.

RESULTS

The prevalence of MCI was 65.6 % and that of MetS was 45.7 %. Compared to those without MetS, those with MetS had significantly poorer cognitive functioning on the all cognitive domain of the MoCA, even after controlling for age, education, severity of the depression and duration of illness. Low High-Density Lipoprotein (HDL) was found to have a positive correlation with MoCA. Higher age, lower education, higher duration of illness and use of higher numbers of medications were associated with significantly lower score on MoCA.

CONCLUSION

Presence of MetS among persons with hypertension is associated with cognitive decline. Hence, there is a need to monitor and manage other parameters of MetS among patients with hypertension, to reduce the risk of cognitive decline and future dementia.

Cerebrovascular risk factors impact frontoparietal network integrity and executive function in healthy ageing

Healthy cognitive ageing is a societal and public health priority. Cerebrovascular risk factors increase the likelihood of dementia in older people but their impact on cognitive ageing in younger, healthy brains is less clear. The UK Biobank provides cognition and brain imaging measures in the largest population cohort studied to date. Here we show that cognitive abilities of healthy individuals (N = 22,059) in this sample are detrimentally affected by cerebrovascular risk factors. Structural equation modelling revealed that cerebrovascular risk is associated with reduced cerebral grey matter and white matter integrity within a fronto-parietal brain network underlying executive function. Notably, higher systolic blood pressure was associated with worse executive cognitive function in mid-life (44-69 years), but not in late-life (>70 years). During mid-life this association did not occur in the systolic range of 110-140 mmHg. These findings suggest cerebrovascular risk factors impact on brain structure and cognitive function in healthy people.

The association of the metabolic syndrome with target organ damage: focus on the heart, brain, and central arteries

INTRODUCTION

The metabolic syndrome (MetS) is an adverse metabolic state composed of obesity, hyperglycemia/pre-diabetes, hypertension, and dyslipidemia. It substantially increases the risk of type 2 diabetes, cardiovascular disease (CVD) and mortality, and has a huge impact on public health.

AREA COVERED

The present review gives an update on the definition and prevalence of MetS, and its impact on cardiac structure and function as well as on the brain and central arteries. The association with CVD and mortality risk is discussed. Focus is mainly directed toward the subclinical target organ damage related to MetS. Data is also critically reviewed to provide evidence on the incremental prognostic value of overall MetS over its individual components.

EXPERT COMMENTARY

MetS is a clinical risk condition associated with subclinical and clinical CVD and mortality. Roughly, 30% of the world population suffer from MetS. As all components of the MetS are modifiable, optimal preventive and therapeutic measures should be initiated to improve CV risk control, particularly aggressively treating hypertension and hyperglycemia, and encouraging people to adopt healthy lifestyle as early as possible is of great importance.

Association of Early-Onset Alzheimer Disease With Elevated Low-Density Lipoprotein Cholesterol Levels and Rare Genetic Coding Variants of APOB

Importance

Early-onset Alzheimer disease (EOAD) is a rare form of Alzheimer disease (AD) with a large genetic basis that is only partially understood. In late-onset AD, elevated circulating cholesterol levels increase AD risk even after adjusting for the apolipoprotein E ε4 (APOE E4) allele, a major genetic factor for AD and elevated cholesterol levels; however, the role of circulating cholesterol levels in EOAD is unclear.

Objectives

To investigate the association between circulating cholesterol levels and EOAD and to identify genetic variants underlying this possible association.

Design, Setting, and Participants

In this case series, plasma cholesterol levels were directly measured in 267 samples from the AD research centers (ADRCs) of Emory University and University of California, San Francisco, collected from January 21, 2009, through August 21, 2014. The association between cholesterol and EOAD was examined using multiple linear regression. To determine the underlying genetic variants, APOB, APP, PSEN1, and PSEN2 were sequenced in samples from 2125 EOAD cases and controls recruited from 29 ADRCs from January 1, 1984, through December 31, 2015. Data were analyzed from November 23, 2016, through April 10, 2018.

Exposures

Clinical diagnosis, age at clinical diagnosis, plasma cholesterol measures (total cholesterol, low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol, triglycerides, and apolipoprotein B), and genetic variants in APOE, APP, PSEN1, PSEN2, and APOB.

Main Outcomes and Measures

The primary outcome was the association between EOAD and plasma cholesterol measures. The secondary outcome was the association between EOAD and the burden of genetic variants in APOB.

Results

Of the 2125 samples that underwent genetic sequencing, 1276 were from women (60.0%) and 654 (30.8%) were from patients with EOAD (mean [SD] ages, 55.6 [4.3] years for cases and 72.0 [9.6] years for controls). APOE E4 explained 10.1% of the variance of EOAD. After controlling for APOE E4, EOAD cases had higher levels of total cholesterol (mean difference [SE], 21.9 [5.2] mg/dL; P = 2.9 × 10-5), LDL-C (mean difference [SE], 22.0 [4.5] mg/dL; P = 1.8 × 10-6), and ApoB (mean difference [SE], 12.0 [2.4] mg/dL; P = 2.0 × 10-6) than controls in 267 frozen samples. Approximately 3% of EOAD cases carried known AD-causing mutations. Gene-based rare variant burden testing in 2066 samples showed that rare APOB coding variants were significantly more abundant in EOAD cases after adjusting for sex, APOE E4, genetic principal components, ADRC center, and batch (effect size, 0.20; P = 4.20 × 10-4).

Conclusions and Relevance

Elevated LDL-C levels were associated with higher probability of having EOAD, and EOAD cases were enriched for rare coding variants in APOB, which codes for the major protein of LDL-C. Collectively, these novel findings highlight the important role of LDL-C in EOAD pathogenesis and suggest a direct link of APOB variants to AD risk.

Genetic Underpinnings of Increased BMI and Its Association With Late Midlife Cognitive Abilities

Objectives: First, we test for differences in various cognitive abilities across trajectories of body mass index (BMI) over the later life course. Second, we examine whether genetic risk factors for unhealthy BMIs—assessed via polygenic risk scores (PRS)—predict cognitive abilities in late-life. Methods: The study used a longitudinal sample of Vietnam veteran males to explore the associations between BMI trajectories, measured across four time points, and later cognitive abilities. The sample of 977 individuals was drawn from the Vietnam Era Twin Study of Aging. Cognitive abilities evaluated included executive function, abstract reasoning, episodic memory, processing speed, verbal fluency, and visual spatial ability. Multilevel linear regression models were used to estimate the associations between BMI trajectories and cognitive abilities. Then, BMI PRS was added to the models to evaluate polygenic associations with cognitive abilities. Results: There were no significant differences in cognitive ability between any of the BMI trajectory groups. There was a significant inverse relationship between BMI-PRS and several cognitive ability measures. Discussion: While no associations emerged for BMI trajectories and cognitive abilities at the phenotypic levels, BMI PRS measures did correlate with key cognitive domains. Our results suggest possible polygenic linkages cutting across key components of the central and peripheral nervous system.

Plasma lipidomic biomarker analysis reveals distinct lipid changes in vascular dementia

Vascular dementia (VaD) is a complex neurocognitive disorder secondary to a variety of cerebrovascular lesions. Numerous studies have shown that lipid metabolism is involved in the pathobiology of the disease. We examined the plasma lipid profiles in VaD, with the expectation of identifying reliable lipid biomarkers for VaD. 49 VaD patients and 48 healthy controls were recruited from Bankstown-Lidcombe Hospital in Sydney, Australia. Lipids were extracted by single phase 1-butanol/methanol, and untargeted analysis was performed by liquid chromatography coupled-mass spectrometry (LC–MS/MS). Univariate analysis of variance was used to examine the differences in lipid classes and individual lipids between VaD and control groups. In an independent sample of 161 subjects from the Older Australian Twins Study (OATS), elastic net penalization for the generalized linear model (Glmnet) and Random Forest were applied to the lipid levels to subcategorise the sample into vascular cognitive impairment and controls. Most lipids belonging to the classes of ceramides (Cer), cholesterol esters (ChE) and phospholipids were significantly lower in VaD plasma, while glycerides were elevated compared to controls. Levels of ChE, Cer and the two lipid classes together achieved the best accuracy in discriminating VaD from controls, with more than 80% accuracy. The probable VaD group in the OATS sample predicted by the lipid levels showed greater impairment in most cognitive domains, especially attention and processing speed and executive function from controls but did not differ in white matter hyperintensities and DTI measures. As a conclusion, plasma lipids levels, in particular Cer and ChE, are abnormal in VaD and may help discriminate them from healthy controls. Understanding the basis of these differences may provide insights into the pathobiology of VaD.

Blood Metabolite Signatures of Metabolic Syndrome in Two Cross-Cultural Older Adult Cohorts

Metabolic syndrome (MetS) affects an increasing number of older adults worldwide. Cross-cultural comparisons can provide insight into how factors, including genetic, environmental, and lifestyle, may influence MetS prevalence. Metabolomics, which measures the biochemical products of cell processes, can be used to enhance a mechanistic understanding of how biological factors influence metabolic outcomes. In this study we examined associations between serum metabolite concentrations, representing a range of biochemical pathways and metabolic syndrome in two older adult cohorts: The Tsuruoka Metabolomics Cohort Study (TMCS) from Japan (n = 104) and the Baltimore Longitudinal Study of Aging (BLSA) from the United States (n = 146). We used logistic regression to model associations between MetS and metabolite concentrations. We found that metabolites from the phosphatidylcholines-acyl-alkyl, sphingomyelin, and hexose classes were significantly associated with MetS and risk factor outcomes in both cohorts. In BLSA, metabolites across all classes were uniquely associated with all outcomes. In TMCS, metabolites from the amino acid, biogenic amines, and free fatty acid classes were uniquely associated with MetS, and metabolites from the sphingomyelin class were uniquely associated with elevated triglycerides. The metabolites and metabolite classes we identified may be relevant for future studies exploring disease mechanisms and identifying novel precision therapy targets for individualized medicine.

Alzheimer's Disease and its Related Dementias among Asian Americans, Native Hawaiians, and Pacific Islanders: A Scoping Review

BACKGROUND

The Asian American, Native Hawaiian, and Pacific Islander (AANHPI) aging population is rapidly growing and the burden of Alzheimer's disease and its related dementias (ADRD) will likely mirror this demographic growth. AANHPIs face significant barriers in obtaining timely ADRD diagnosis and services; yet little is known about ADRD in this population.

OBJECTIVE

The study objective is to conduct a systematic review on the published literature on ADRD among AANHPIs to identify gaps and priorities to inform future research and action plans.

METHODS

The systematic review was conducted following the PRISMA Protocol for Systematic Reviews. Co-author (TR), an experienced Medical Librarian, searched PubMed, EMBASE, PsycINFO, Cochrane Central of Clinical Trials, Ageline, and Web of Science for peer-reviewed articles describing ADRD among AANHPIs. The search was not limited by language or publication date. Each citation was reviewed by two trained independent reviewers. Conflicts were resolved through consensus.

RESULTS

The title/abstract and full texts of 1,447 unique articles were screened for inclusion, yielding 168 articles for analysis. Major research topics included prevalence, risk factors, comorbidities, interventions and outreach, knowledge and attitudes, caregiving, and detection tools. A limited number of studies reported on national data, on NHPI communities generally, and on efficacy of interventions targeting AANHPI communities.

CONCLUSION

To our knowledge, this is the first systematic review on ADRD among AANHPI populations. Our review provides a first step in mapping the extant literature on ADRD among this underserved and under-researched population and will serve as a guide for future research, policy, and intervention.

Elevated serum TC and LDL-C levels in Alzheimer's disease and mild cognitive impairment: A meta-analysis study

Serum lipid levels such as triglyceride and cholesterol has been reported to play an important role in the pathophysiological process of Alzheimer disease (AD) and mild cognitive impairment (MCI). However, it still remains controversial in different studies. Here, we performed a meta-analysis to assess the importance of serum levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) in AD and MCI patients. PubMed, China National Knowledge Infrastructure (CNKI) system database were used to identify 17 studies (10 AD-only + 4 MCI-only + 3 shared AD/MCI), including 2333 cases and 3615 healthy controls (HC). We found that compared with HC, both the serum TC levels [SMD = 0.58; 95%CI (0.25, 0.90); P = 0.001) and the serum LDL-C levels [SMD = 0.7780; 95%CI (0.3940, 1.1521); P = 0.000] were higher in cognitive impairment population (including AD and MCI) than those in HC, respectively. Furthermore, we analyzed the serum TC and LDL-C levels in AD and MCI patients. We found that the serum TC levels [SMD = 0.76; 95% CI (0.13, 1.40); P = 0.019]1 and the LDL-C levels [SMD = 1.40; 95% CI (0.70, 2.10; P = 0.000] were increased in AD patients. In the MCI patients, the serum TC levels [SMD = 0.30; 95%CI (0.01, 0.59); P = 0.041] had a significantly upward trend, while the LDL-C levels had no significant change, compared with HC subjects. However, there is no significant changes in HDL-C and TG levels in AD or MCI patients. Therefore, our results suggested that the elevated TC and LDL-C levels may be a potential risk factor for cognitive impairment.

Association Between Waist Circumference and Dementia in Older Persons: A Nationwide Population-Based Study

OBJECTIVE

This study examined whether a positive association exists between waist circumference (WC) and dementia among older persons.

METHODS

The study population comprised 872,082 participants aged 65 years and older who participated in a Korean national health screening examination between January 1, 2009, and December 31, 2009. Adjusted hazard ratios and 95% CIs for dementia during follow-up from 2009 to 2015 were calculated according to baseline BMI and WC categories.

RESULTS

After a multivariate adjustment that included BMI, the hazard ratios for dementia showed a stepwise increase according to the increase in WC categories by 5 cm from 85 to 90 cm in men and from 80 to 85 cm in women until ≥ 110 cm (from 1.06 [95% CI: 1.03-1.09] to 1.64 [95% CI: 1.37-1.94] in men and from 1.04 [95% CI: 1.02-1.07] to 1.58 [95% CI: 1.36-1.84] in women). The influence of the current WC category for abdominal obesity on the risk of dementia was different according to BMI; especially, the normal weight men and women with abdominal obesity had a prominent increased risk of dementia compared with those without abdominal obesity.

CONCLUSIONS

Abdominal obesity, as measured by WC, was associated with significantly increased risk of dementia after adjustment for general obesity.

Metabolic Syndrome, Mild Cognitive Impairment, and Dementia: A Meta-Analysis of Longitudinal Studies

OBJECTIVE

A systematic review and a meta-analysis of both clinical and population-based studies was undertaken according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement to clarify whether Metabolic Syndrome (MetS) is a risk or a protective factor for incident dementia, Alzheimer disease (AD), and vascular dementia (VaD), and whether it's involved in progression to dementia in patients affected by mild cognitive impairment (MCI).

METHODS

Search terms included ("metabolic syndrome" OR "syndrome x" OR "plurimetabolic syndrome") AND ("dementia" OR "Alzheimer disease" OR "vascular dementia" OR "mild cognitive impairment" OR "MCI"). Research was restricted to articles published in English between January 1, 2000 and August 31, 2018. No age limit was set.

RESULTS

At the end of the selection procedure, nine longitudinal studies were selected for the meta-analysis: six studies enrolled cognitively well-functioning participants and three studies involved MCI patients. A total of 18,313 participants aged older than 40 years with mean MetS prevalence of 22.7% were followed on average for 9.41years. A fixed model was used to estimate pooled hazard ratios and 95% confidence intervals.

CONCLUSION

No statistically significant pooled association emerged between MetS and incident dementia and AD. MetS increased the incidence of pure VaD. MetS increased the risk of progression from MCI to dementia. Follow-up length might be a key factor in investigating these associations further. Because MetS is constituted by a set of potentially modifiable factors, further studies with longer follow-up and repeated assessment of both MetS and cognitive status are desirable to draw definite conclusions.

High HOMA-IR Index in Healthcare Shift Workers

Background and objectives: Evidence shows that shift work may be correlated with insulin resistance (IR). Therefore its estimation in clinical and prevention practice is of great significance. A cross-sectional study was performed to examine the Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) Index among healthcare shift workers (HCSW). Materials and Methods: A total of 272 healthcare workers (HCWs) were invited to participate in the study within an occupational surveillance framework, 137 were HCSW while 135 were healthcare non-shift workers (HCNSW). Fasting glucose, insulin, and HOMA-IR Index were evaluated in each participant and correlated with shift workers. Results: Indicators of glucose metabolism were significantly higher in HCSW p < 0.001, and logistic regression analysis confirmed a significant positive association between increased values of HOMA-IR Index and shift workers (p < 0.05). Conclusions: Shift work could be a risk factor in developing insulin resistance and metabolic syndrome.