The Relationships Between Components of Metabolic Syndrome and Mild Cognitive Impairment Subtypes: A Cross-Sectional Study of Japanese Older Adults

Cognitive Profile and Cardiovascular Risk Factors in Older Adults with Mild Cognitive Impairment

The prevalence of cardiovascular risk factors (CVRFs) in the older adults population and their specific impact on their cognitive profiles still requires further research. For this purpose, a cross-sectional study was carried out to describe the presence of CVRFs and their association with cognitive performance in a sample of older adults (65-85 years old) with Mild Cognitive Impairment (MCI). Participants (n = 185) were divided into three groups concerning their cardiovascular risk level determined by the presence of different CVRFs, including Type 2 Diabetes (T2D), dyslipidemia, hypertension, and obesity. The primary outcome measures were the participant's scores in the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Sociodemographic, clinical, and psychosocial data were collected. Non-parametrical statistical analyses and effect sizes were calculated. Findings revealed that a greater presence of CVRFs was not associated with a worse overall cognitive performance. High-risk patients were more likely to have significantly worse performance in the attentional domain compared to medium-risk (p = 0.029, r = 0.42) and compared to low-risk (p = 0.041, r = 0.35), specifically in the digits repetition subtest (p = 0.042). T2D alone was the CVRF associated with cognitive differences (p = 0.037, r = 0.32), possibly mediated by the duration of the condition. Consequently, a higher presence of CVRFs did not lead to a worse overall cognitive performance. However, high-risk individuals were more likely to experience cognitive impairment, particularly in the attentional domain. T2D played a significant role in these cognitive profile differences, possibly influenced by its duration.

Social isolation and risk of disability in older adults: Effect modification of metabolic syndrome

PURPOSE

Delaying the onset of disabilities is a social challenge, especially in an aging society. Social isolation (SI) and metabolic syndrome (MetS) can coexist and pose the risks of disability onset. However, their interaction is not proven in older adults. Therefore, this study investigated whether SI combined with MetS exacerbates disability onset in older adults.

MATERIALS AND METHODS

A total of 3,738 community-dwelling older adults underwent a health check-up. After baseline assessments, we followed them up to assess disability incidence for five years. SI was defined as a condition in which two or more of the following measures were met: domestic isolation, less social contact, and social disengagement. MetS was defined according to the criteria of the International Diabetes Federation. We used Cox proportional hazard regression used to identify the interaction effect of SI and MetS on the risk of disability onset after adjusting for potential confounding factors.

RESULTS

Multivariate Cox proportional hazard regression showed a significant interaction effect of SI and MetS on disability onset. In the subgroup analysis stratified by MetS status, SI was identified as a risk factor for disability onset only in the MetS group, but not in the non-MetS group.

CONCLUSIONS

This five-year longitudinal study showed that the co-occurrence of SI and MetS increased the risk of disability onset in older adults. This indicates that the assessment of MetS in socially isolated older adults is important for healthcare providers to delay the onset of disabilities.

Metabolic syndrome and cognitive deficits in the Greek cohort of Epirus Health Study

BACKGROUND

Metabolic syndrome is considered an important risk factor for cognitive decline and dementia. However, the evidence in middle-aged individuals is still conflicting. The aim of the study was to explore the association between metabolic syndrome and its individual components with cognitive function and to investigate possible interaction between sex, age and genetic predisposition for metabolic syndrome and Alzheimer's disease in a middle-aged Greek cohort.

METHODS

A total of 2,077 healthy adults (mean age: 46.7 years) were included in the primary cross-sectional analysis and 305 of them in secondary prospective analyses. Metabolic syndrome was defined by the revised National Cholesterol Education-Adult Treatment Panel III and the International Diabetes Federation criteria. Cognitive function was measured primarily with the Trail Making, Verbal fluency and Logical Memory test, and in secondary prospective analyses with online versions of Posner cueing task, an emotional recognition task, Corsi block-tapping task and Stroop task.

RESULTS

Multivariable linear regressions showed an association of metabolic syndrome with lower performance in attention (β=1.62 seconds, 95% CI=0.20, 3.04) and memory (β=-0.62 words, 95% CI=-1.19, -0.05) that could be driven by associations with elevated fasting glucose and abdominal obesity. Similar associations were observed in the secondary prospective analyses.

CONCLUSION

In summary, metabolic syndrome was associated with cognitive deficits in domains related with the cognitive profile of vascular cognitive impairment.

Night shift work and the risk of metabolic syndrome: Findings from an 8-year hospital cohort

Objectives

Studies concerning the risk of metabolic syndrome associated with night work have shown inconsistent findings, due to imprecise working time data and cross-sectional design. We used register-based daily working time data to examine the risk of incident metabolic syndrome associated with night shift work.

Methods

Working time data collected between 2010 and 2018 of 5775 Taiwanese hospital workers were used to identify night shift workers and to calculate the number of night shifts. Metabolic syndrome was identified by annual occupational health examination results, which were linked to the working time data. Logistic regression models and generalized estimating equations were used to examine the association between night shift work and metabolic syndrome and the 5 components of metabolic syndrome.

Results

Night shift work is associated with a higher risk of developing metabolic syndrome (adjusted OR = 1.36, 95% CI = 1.04 to 1.78) and high waist circumference (adjusted OR = 1.27, 95% CI = 1.07 to 1.78) compared to day work. Among night shift workers, increased number of night shifts was associated with high blood pressure (adjusted OR = 1.15, 95% CI = 1.01 to 1.31).

Conclusions

Night shift work is associated with metabolic risk factors. Long-term effects of circadian rhythm disruption on metabolic disturbances needs to be further studied.

Metabolic Syndrome and Cognitive Function

PURPOSE OF REVIEW

Metabolic syndrome (MetS) is a cluster of cardiovascular disease risk factors that are related to several adverse health outcomes, including poor cognitive function. This review seeks to summarize and critically review select recent findings on the association between MetS and cognition.

RECENT FINDINGS

MetS was associated with lower domain-specific and global cognitive function in most cross-sectional studies, but findings from longitudinal studies are not consistent. The associations varied depending on age, sex, cognitive test, genetic susceptibility, and the duration of follow-up in prospective studies. MetS was associated with a higher risk of mild cognitive impairment (MCI) and progression from MCI to dementia, particularly vascular dementia. Among MetS components, high blood pressure, high waist circumference, and hyperglycemia were the strongest predictors of cognitive function. MetS is associated with higher risk of cognitive impairment. Research is needed on how preventing or treating MetS affects cognition.

Association between apathy and satisfaction with meaningful activities in older adults with mild cognitive impairment: A population-based cross-sectional study

OBJECTIVES

This cross-sectional study aimed to clarify the relationship between apathy, meaningful activities, and satisfaction with such activities of older adults with mild cognitive impairment (MCI).

METHODS

We analyzed 235 older adults with MCI (≥65 years, mean age: 76.9 ± 6.4 years, women: 63.4%) who participated in a community-based health check survey (Tarumizu Study 2018). MCI was defined as at least 1.5 SD below the reference threshold (age- and education-adjusted score) on one or more of the computerized cognitive test including memory, attention, executive functions, and processing speed. Apathy symptoms were assessed using three of the 15 items of Geriatric Depression Scale. Participants selected meaningful activities from the 95 activities of the Aid for Decision-Making in Occupation Choice and evaluated their satisfaction and performance.

RESULTS

Apathy in MCI was prevalent by 23.8%. The categories of meaningful activities revealed no difference, with, or without apathy. Logistic regression analysis showed that activity satisfaction was significantly associated with apathy after adjusting for age, sex, education, instrumental activities of daily living, depressive symptoms, and MCI subtype (OR, 0.62; 95% CI, 0.44-0.88, p = 0.008).

CONCLUSIONS

Satisfaction with the activities that are deemed meaningful is associated with apathy among community-dwelling older adults with MCI.

Metabolic Syndrome: Is It Time to Add the Central Nervous System?

Metabolic syndrome (MS) is a set of cardio-metabolic risk factors that includes central obesity, hyperglycemia, hypertension, and dyslipidemias. The syndrome affects 25% of adults worldwide. The definition of MS has evolved over the last 80 years, with various classification systems and criteria, whose limitations and benefits are currently the subject of some controversy. Likewise, hypotheses regarding the etiology of MS add more confusion from clinical and epidemiological points of view. The leading suggestion for the pathophysiology of MS is insulin resistance (IR). IR can affect multiple tissues and organs, from the classic “triumvirate” (myocyte, adipocyte, and hepatocyte) to possible effects on organs considered more recently, such as the central nervous system (CNS). Mild cognitive impairment (MCI) and Alzheimer’s disease (AD) may be clinical expressions of CNS involvement. However, the association between MCI and MS is not understood. The bidirectional relationship that seems to exist between these factors raises the questions of which phenomenon occurs first and whether MCI can be a precursor of MS. This review explores shared pathophysiological mechanisms between MCI and MS and establishes a hypothesis of a possible MCI role in the development of IR and the appearance of MS.

Absolute Cardiovascular Disease Risk Is Associated With the Incidence of Non-amnestic Cognitive Impairment in Japanese Older Adults

Background

The estimated absolute cardiovascular disease (CVD) risk level is known to be a useful surrogate marker for future cognitive impairment; however, evidence regarding its predictive validity in terms of cognitive subtypes is limited. We aimed to examine subtype-dependent differences in the associations between absolute CVD risk and the incidence of cognitive impairment in a community-dwelling older Japanese cohort.

Methods and Results

This study comprised 1,641 cognitively intact older Japanese participants without CVDs at baseline. We estimated absolute CVD risk using WHO region-specific risk estimation charts and included age, sex, diabetes mellitus, smoking, systolic blood pressure, and total cholesterol at baseline, and the CVD risk level was stratified into the three following risk categories: low (<10%), moderate (10 to <20%), and high (≥20%). Objective cognitive screening was performed using a multicomponent neurocognitive test at baseline and follow-up, and the incidence of cognitive impairment over 48 ± 2 months was determined. The incidence of cognitive impairment in low-, moderate-, and high-CVD risk participants was 1.2, 3.0, and 5.4%, respectively, for amnestic subtypes and 5.8, 10.1, and 14.0%, respectively, for non-amnestic subtypes. After adjusting for potential confounding factors, the absolute CVD risk level was significantly associated with non-amnestic impairment but not with amnestic impairment.

Conclusions

The absolute CVD risk estimated using region-specific risk estimation charts in old age is useful to predict incidence of cognitive impairment. Strategies to screen populations at risk of cognitive impairment and to prevent progression to dementia should be cognitive subtype-specific.

Contribution of Components of Metabolic Syndrome to Cognitive Performance in Middle-Aged Adults

Introduction

Metabolic syndrome (MetS) has been associated with impaired cognition in different cognitive domains. This study investigated the association between MetS and cognitive functioning in middle-aged Bulgarians across different definitions of MetS severity.

Material and Methods

Our cross-sectional sample included 112 participants (67 free of MetS and 45 with MetS) with a mean age of 50.04 ± 3.31 years. The following MetS variables were considered—presence of MetS, continuously measured MetS components, dichotomized MetS components, number of MetS components present, and Metabolic Syndrome Severity Score (MSSS). Participants’ cognitive performance was assessed using the Consortium to Establish a Registry for Alzheimer’s Disease Neuropsychological Battery (CERAD-NB). We employed multivariate regression models to investigate the associations between different measures of MetS severity and CERAD-NB total and subtest scores.

Results

Bivariate analyses showed that the CERAD-NB total score was significantly higher in women, participants with a university degree, those with normal blood pressure, normal waist circumference, and low triglyceride levels, compared with their counterparts. MetS participants had lower CERAD-NB total score (78.87 ± 6.89 vs. 84.97 ± 7.84) and specifically performed poorer on the subtest Word List Recall (7.16 ± 1.52 vs. 7.99 ± 1.52). These findings persisted after controlling for age, gender, and education. Next, generalized linear regression indicated that the CERAD-NB total score was lower in participants with MetS (β = −4.86; 95% confidence interval [CI]: −7.60, −2.11), those with more MetS components (β = −8.31; 95% CI: −14.13, −2.50 for fours vs. 0 components) and with an increase in MSSS (β = −3.19; 95% CI: −4.67, −1.71). Hypertension independently contributed to lower CERAD-NB total score (β = −4.00; 95% CI: −6.81, −1.19).

Conclusions

Across several definitions, MetS was associated with lower cognitive functioning, and MetS severity appeared to be a better predictor than most MetS components. Recognizing and reducing severity of MetS components might be helpful in supporting cognitive functioning. Further longitudinal research is needed to shed more light on the relationship between MetS and cognitive functioning across the life span.

Prevalence of mild cognitive impairment in community-dwelling Chinese populations aged over 55 years: a meta-analysis and systematic review

Background

Mild cognitive impairment (MCI) is an intermediate phase between normal cognitive ageing and overt dementia, with amnesic MCI (aMCI) being the dominant subtype. This study aims to synthesise the prevalence results of MCI and aMCI in community-dwelling populations in China through a meta-analysis and systematic review.

Methods

The study followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) protocol. English and Chinese studies published before 1 March 2020 were searched from ten electronic bibliographic databases. Two reviewers screened for relevance of the studies against the pre-defined inclusion and exclusion criteria and assessed the quality of the included studies using the Risk of Bias Tool independently. A random-effect model was adopted to estimate the prevalence of MCI and aMCI, followed by sub-group analyses and meta-regression. Sensitivity and publication bias tests were performed to verify the robustness of the meta-analyses.

Results

A total of 41 studies with 112,632 participants were included in the meta-analyses. The Chinese community-dwelling populations over 55 years old had a pooled prevalence of 12.2% [95% confidence interval (CI): 10.6, 14.2%] for MCI and 10.9% [95% CI, 7.7, 15.4%] for aMCI, respectively. The prevalence of MCI increased with age. The American Psychiatric Association’s Diagnostic tool (DSM-IV) generated the highest MCI prevalence (13.5%), followed by the Petersen criteria (12.9%), and the National Institute on Aging Alzheimer’s Association (NIA-AA) criteria (10.3%). Women, rural residents, and those who lived alone and had low levels of education had higher MCI prevalence than others.

Conclusion

Higher MCI prevalence was identified in community-dwelling older adult populations in China compared with some other countries, possibly due to more broadened criteria being adopted for confirming the diagnosis. The study shows that aMCI accounts for 66.5% of MCI, which is consistent with findings of studies undertaken elsewhere.

Systematic review registration number

PROSPERO CRD42019134686.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-020-01948-3.

Metabolic Syndrome and Cognitive Function: Cross-Sectional Study on Community-Dwelling Non-Demented Older Adults in Japan

AIM

This is a cross-sectional study of relation between metabolic syndrome and cognitive function in community-dwelling non-demented older adults in Japan. We examine the effect of metabolic syndrome and its components on global cognitive function. We also aim to clarify differences of specific cognitive domains between the subjects with and without metabolic syndrome.

METHODS

We studied 2150 subjects aged between 60 and 90 years whose scores on mini mental state examination (MMSE) were over 23 points. We analyzed difference in MMSE scores between the subjects with and without metabolic syndrome. Logistic regression analysis was performed with MMSE score as the dependent variable and metabolic syndrome components as the independent variable adjusted with age. We also examined differences in attention, logical memory, and verbal and category fluency between the subjects with and without metabolic syndrome.

RESULTS

MMSE scores were not significantly different between subjects with and without metabolic syndrome. In logistic regression analysis, the score of MMSE was significantly negatively associated with triglycerides in males and significantly negatively associated with abdominal circumference in females. Subjects with metabolic syndrome showed significantly lower performance of attention tasks compared to subjects without metabolic syndrome.

CONCLUSIONS

Our results suggest that in community-dwelling non-demented Japanese older adults, attention but not global cognitive function may be impaired by metabolic syndrome. Inverted association between some components of metabolic syndrome and global cognitive function indicate necessity of further studies on the relation between undernutrition and cognitive function.