Prevalence, risk and protective factors for mild cognitive impairment in a population-based study of Singaporean elderly

Modifiable risk factors for mild cognitive impairment among cognitively normal community-dwelling older adults: A systematic review and meta-analysis

Although numerous studies have investigated modifiable risk factors for mild cognitive impairment (MCI) among community-dwelling seniors, no meta-analysis has summarized these findings. Five databases were searched from January 1, 2000, to December 30, 2023. The protocol was registered with PROSPERO. Data were extracted and reported following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Relevant meta-analyses of modifiable risk factors were performed. The evidence of each factor was assessed by the GRADE for cohort studies. Of 16,651 citations, 87 studies involving 225,584 community-dwelling seniors were included. Fourteen meta-analyses involving 20 studies with 44,199 participants were performed. The analyses revealed low-to-moderate-quality evidence supporting that diabetes, 2 or more comorbidities, anxiety, apathy, depressive symptoms, and physical frailty were risk factors for incident MCI in older adults. Conversely, hypertension, agitation, and irritability might not be risk factors. Additionally, moderate-quality evidence supports the protective effect of engaging in cognitive-demanding activities on the onset of MCI. Collectively, this study constitutes the first extensive compilation of evidence regarding the various risk factors for the development of MCI in older adults. Our findings hold significant potential to guide the formulation of prevention and management strategies to either prevent or potentially reverse the onset of MCI.

Impact of Taekwondo training on cognitive and physical function in elderly individuals: A comprehensive review of randomized controlled trials

BACKGROUND

Researchers have investigated the physical and psychosocial advantages of Taekwondo for older adults. However, prior studies of Taekwondo's impact on physical function and psychological well-being in this demographic have produced inconsistent findings. Thus, this systematic review aimed to assess how Taekwondo practice affects the physical function and psychological well-being of older adults.

METHODS

We systematically searched PubMed, EMBASE, CINAHL, SPORTDiscus, Scopus, Korea Education and Research Information Service, Korean Studies Information Service System, Korean National Assembly Library, Research Information Sharing Service, National Digital Science Library, and China National Knowledge Infrastructure from their inception to December 2023. Two reviewers independently selected and extracted data from each study. We calculated effect sizes using a random-effects model with a 95 % confidence interval (CI) and evaluated study quality using the Physiotherapy Evidence Database scale.

RESULTS

This review included ten studies with 227 participants aged 66.1-73.6 years. The meta-analysis revealed significant enhancements in cognitive function [Korean Version of Mini-Mental State Examination, standard mean difference (SMD) = 0.700, 95 % CI (0.364-1.037), I2 = 0 %, p < .001], blood indicators [β-amyloid, SMD = 0.613, 95 % CI (0.103-1.123), I2 = 34.920 %, p < .05; brain-derived neurotrophic factor, SMD = 0.566, 95 % CI (0.166-0.966), I2 = 0 %, p < .01; high-density lipoprotein cholesterol, SMD = 0.677, 95 % CI (0.357-0.966), I2 = 0 %, p < .001; low-density lipoprotein cholesterol, SMD = 0.809, 95 % CI (0.376-1.242), I2 = 42.621 %, p < .001; and total cholesterol, SMD = 0.979, 95 % CI (0.603-1.356), I2 = 22.221 %, p < .001], and physical function [lean body mass, SMD = 0.465, 95 % CI (0.109-0.821), I2 = 0 %, p < .05, and handgrip strength, SMD = 0.929, 95 % CI (0.194-1.663), I2 = 48.217 %, p < .05].

CONCLUSIONS

This meta-analysis indicates that Taekwondo training is a beneficial therapy with protective effects on cognitive function, physical function, and body composition in older adults. These findings highlight its potential significance in cognitive rehabilitation and physiological health promotion among this demographic population.

Investigating the association between inflammation mediated by mushroom consumption and mild cognitive impairment in Chinese older adults

Background: Chronic inflammatory stimulation is a major risk factor for mild cognitive impairment. Mushroom consumption and inflammatory factors may play an important role in the pathogenesis of mild cognitive impairment. Additionally, consuming mushrooms can reduce the levels of inflammatory cytokines and preserve cognitive function. Therefore, this study aimed to investigate the relationship between mushroom consumption and serum inflammatory cytokines and mild cognitive impairment (MCI). Methods: Binary logistic regression was used to determine the relationship between mushroom consumption and MCI in 550 participants. Subsequently, mediation analysis was used to analyze the relationship between mushroom consumption, inflammatory factors, and the Montreal Cognitive assessment (MoCA) score in 248 participants. Results: Mushroom consumption was associated with MCI (odds ratio = 0.623, 95% confidence interval = 0.542-0.715, P < 0.001). The association between mushroom intake and MCI was mediated by interleukin-6 (IL-6) and hypersensitive C-reactive protein (hs-CRP), and the MoCA score was 12.76% and 47.59%, respectively. Conclusion: A high intake of mushrooms was associated with a low risk of MCI. Serum inflammatory factors including IL-6 and hs-CRP play a partial mediating role between mushroom intake and the MoCA score, and the underlying mechanism needs to be further explored.

Establishment of a mild cognitive impairment risk model in middle-aged and older adults: a longitudinal study

BACKGROUND

Early identification individuals at high risk of mild cognitive impairment (MCI) is essential for prevention and intervention strategies of dementia, such as Alzheimer's disease. MCI prediction considering the interdependence of predictors in longitudinal data needs to be further explored. We aimed to employ machine learning (ML) to develop and verify a prediction model of MCI.

METHODS

In a longitudinal population-based cohort of China Health and Retirement Longitudinal Study (CHARLS), 8390 non-MCI participants were enrolled. The diagnosis of MCI was based on the aging-associated cognitive decline (AACD), and 13 factors (gender, education, marital status, residence, diabetes, hypertension, depression, hearing impairment, social isolation, physical activity, drinking status, body mass index and expenditure) were finally selected as predictors. We implemented a long short-term memory (LSTM) to predict the MCI risks in middle-aged and older adults within 7 years. The Receiver Operating Characteristic curve (ROC) and calibration curve were used to evaluate the performance of the model.

RESULTS

Through 7 years of follow-up, 1925 participants developed MCI. The model for all incident MCI achieved an AUC of 0.774, and its deployment to the participants followed 2, 4, and 7 years achieved results of 0.739, 0.747, and 0.750, respectively. The model was well-calibrated with predicted probabilities plotted against the observed proportions of cognitive impairment. Education level, gender, marital status, and depression contributed most to the prediction of MCI.

CONCLUSIONS

This model could be widely applied to medical institutions, even in the community, to identify middle-aged and older adults at high risk of MCI.

Usefulness of the Visual Cognitive Assessment Test in Detecting Mild Cognitive Impairment in the Community

BACKGROUND

A delay in the detection of mild cognitive impairment (MCI) in the community delays the opportunity for early intervention. Accurate tools to detect MCI in the community are lacking. The Visual Cognitive Assessment Test (VCAT) is a visual based cognitive test useful for multilingual populations without the need for translation.

OBJECTIVE

Here, we evaluate the usefulness of VCAT in detecting MCI in a community population in Singapore.

METHODS

We recruited 301 participants from the community who completed a detailed neuropsychological assessment and 170 of them completed a 3T magnetic resonance imaging (MRI) brain scan. We performed a receiver operating characteristics analysis to test the diagnostic performance of VCAT compared to Montreal Cognitive Assessment (MoCA) in distinguishing MCI from cognitively normal (CN) by measuring area under the curve (AUC). To test for the association of VCAT with structural MRI, we performed a Pearson's correlation analysis for VCAT and MRI variables.

RESULTS

We recruited 39 CN and 262 MCI participants from Dementia Research Centre (Singapore). Mean age of the cohort was 63.64, SD = 9.38, mean education years was 13.59, SD = 3.70 and majority were women (55.8%). VCAT was effective in detecting MCI from CN with an AUC of 0.794 (95% CI 0.723-0.865) which was slightly higher than MoCA 0.699 (95% CI 0.621-0.777). Among subjects with MCI, VCAT was associated with medial temporal lobe atrophy (ρ = -0.265, p = 0.001).

CONCLUSIONS

The VCAT is useful in detecting MCI in the community in Singapore and may be an effective measure of neurodegeneration.

Remnant cholesterol and mild cognitive impairment: A cross-sectional study

Objective

Emerging evidence suggests that elevated remnant cholesterol (RC) correlates with several health conditions. To explore the association of plasma RC with MCI incidence and the relationship between plasma RC and different domains of cognition in MCI patients.

Methods

Thirty-six MCI patients and 38 cognitively healthy controls (HC) were enrolled in the present cross-sectional study. Using total cholesterol (TC) minus high-density lipoprotein cholesterol (HDL-C) minus low-density lipoprotein cholesterol (LDL-C) as the formula for calculating fasting RC. Cognition was assessed using the Chinese version of the Montreal cognitive assessment (MoCA), Auditory Verbal Learning Test (AVLT), Digit Symbol Substitution Test (DSST), Trail Making Test (TMT), and Rey-Osterrieth Complex Figure Test (ROCF).

Results

Compared to healthy controls, MCI patients had a higher level of RC, the median difference in RC levels between these two groups was 8.13 mg/dl (95.0%CI: 0.97–16.1). Concurrently, plasma RC level was positively associated with MCI risk (OR = 1.05, 95%CI: 1.01–1.10). Notably, elevated RC level was correlated with impaired cognition in MCI patients, such as DSST (pr = −0.45, p = 0.008), ROCF- Long Delayed Recall (pr = −0.45, p = 0.008), AVLT-Immediate Recall (pr = −0.38, p = 0.028), and TMT-A (pr = 0.44, p = 0.009). Conversely, no significant correlation was found between RC and the AVLT-Long Delayed Recall test.

Conclusion

This study found that plasma remnant cholesterol was associated with MCI. Further large longitudinal studies are needed in the future to confirm the results and clarify the cause-and-effect relationship.

Effects of aerobic exercise on global cognitive function and sleep in older adults with mild cognitive impairment: A systematic review and meta-analysis

We conducted a systematic review and meta-analysis to determine the integrated effect of aerobic exercise on cognitive function and sleep in older adults with mild cognitive impairment (MCI) and to optimize exercise methods for improving cognitive function. We searched multiple databases from January 1, 2011, to August 31, 2022, and analyzed 11 studies. Global cognitive function in older adults with MCI undergoing aerobic exercise training was significantly improved (standardized mean difference [SMD]=0.76, 95% confidence interval [CI]:0.37, 1.14), while sleep improvement was not significant (SMD= -2.07 [95% CI: -6.76, 2.62]). In the moderator analysis, aerobic exercise types with cognitive factors, exercise time of 30-50 min per session, and exercise frequency of 5-7 times per week had statistically significant effects on cognitive function improvement. However, meta-regression identified only exercise frequency as a significant moderator of the mean effect size of cognitive function.

Cognitive screening among older adults with diabetes across diverse clinic settings

AIMS

Diabetes increases risk of cognitive dysfunction and dementia, which can make it harder to manage diabetes. We aimed to examine cognitive screening for older adults with diabetes in 1) endocrine (Endo), 2) geriatric (Geri) and 3) multidisciplinary endocrine-geriatric (Geri-Endo), to study differences between these settings and to elucidate risk factors of cognitive dysfunction.

METHODS

We performed cognitive screening for subsets of patients ≥ age 65 with diabetes in one large healthcare system. We compared results and differences from the three clinic types and used adjusted multivariate logistic regression models to predict risk of cognitive dysfunction.

RESULTS

Among 198 patients screened, those in Geri-Endo (N = 86) and Geri (N = 32) were more likely to have lower Mini-Cog scores, higher prevalence of hypertension and cardiovascular (CV) events. Endo and Geri-Endo patients had longer durations of diabetes, higher incidence of hypoglycemia, and were more likely to use insulin. Age > 75 years (p = 0.0105), previous CV events (p = 0.0006) and body mass index < 30 (p = 0.0115) were significantly associated with lower Mini-Cog scores.

CONCLUSIONS

Our study shows that cognitive screening can help identify at risk older adults with diabetes. Thus, yearly screening should be part of routine diabetes care.

Development and validation of a nomogram for predicting mild cognitive impairment in middle-aged and elderly people

BACKGROUND

Mild cognitive impairment (MCI) is a clinical cognitive impairment state between dementia and normal aging. Early identification of MCI is beneficial, and it can delay the development of dementia. We aimed to develop and validate a prediction model to predict MCI of middle-aged and elderly people (aged 45 years and over).

METHODS

According to 478 middle-aged and elderly people (48-85 years old) from a cross-sectional study, we developed and validated a predictive nomogram. The least absolute shrinkage and selection operator (LASSO) regression model and multivariate logistic regression analysis were used to select variables and develop a prediction model. The performance of the nomogram was evaluated in terms of its discriminative power, calibration, and decision curve analysis (DCA).

RESULTS

The predictive nomogram was composed of the following: age, gender, education level, residence, and reading. The model showed good discrimination power (area under receiver-operating characteristic (ROC) curve was 0.8704) and good calibration. Similar results were seen in 10-fold cross-validation. The nomogram showed clinically useful in DCA analysis.

CONCLUSION

This predictive nomogram provides researchers with a practical tool for predicting MCI. The variables included in this nomogram were readily available. The population used for this nomogram was middle-aged and elderly people.

Mild Cognitive Impairment in Rural Areas: Research Advances and Implications for Clinical Practice and Healthcare Policy

Mild cognitive or neurocognitive impairment (MCI) may be more prevalent in rural areas. Differences between rural and urban MCI patients in terms of risk factors, course and prognosis are rarely reported. The present review aims to summarize the latest research on MCI in rural areas. A literature search was performed in the databases of PubMed, Scopus and ScienceDirect for articles published over the last decade. Eleven articles were included in this review, reporting on the differences between rural and urban MCI patients. Several risk factors, such as older age, lack of activities and food insecurity have been associated with MCI in both rural and urban areas, whereas others, such as obesity, adverse childhood experiences and plasma chemokine C-C motif ligand 11 (considered as a potential negative regulator of neurogenesis), differed according to the place of residence. No specific protective factor for rural women has been reported. There is some evidence that MCI may present earlier in rural residents, but that progression to dementia may be more rapid in urban residents. It seems that there may be clinically relevant differences in the onset, course and prognosis of MCI with regards to the place of residence (urban vs rural). Those differences should be taken into account for the design of health policies and service delivery across different settings.

Effect of 3-Month Aerobic Dance on Hippocampal Volume and Cognition in Elderly People With Amnestic Mild Cognitive Impairment: A Randomized Controlled Trial

As an intermediate state between normal aging and dementia, mild cognitive impairment (MCI), especially amnestic MCI (aMCI), is a key stage in the prevention and intervention of Alzheimer’s disease (AD). Whether dancing could increase the hippocampal volume of seniors with aMCI remains debatable. The aim of this study was to investigate the influence of aerobic dance on hippocampal volume and cognition after 3 months of aerobic dance in older adults with aMCI. In this randomized controlled trial, 68 elderly people with aMCI were randomized to either the aerobic dance group or the control group using a 1:1 allocation ratio. Ultimately, 62 of 68 participants completed this study, and the MRI data of 54 participants were included. A specially designed aerobic dance routine was performed by the dance group three times per week for 3 months, and all participants received monthly healthcare education after inclusion. MRI with a 3.0T MRI scanner and cognitive assessments were performed before and after intervention. High-resolution three-dimensional (3D) T1-weighted anatomical images were acquired for the analysis of hippocampal volume. A total of 35 participants (mean age: 71.51 ± 6.62 years) were randomized into the aerobic dance group and 33 participants (mean age: 69.82 ± 7.74 years) into the control group. A multiple linear regression model was used to detect the association between intervention and the difference of hippocampal volumes as well as the change of cognitive scores at baseline and after 3 months. The intervention group showed greater right hippocampal volume (β [95% CI]: 0.379 [0.117, 0.488], p = 0.002) and total hippocampal volume (β [95% CI]: 0.344 [0.082, 0.446], p = 0.005) compared to the control group. No significant association of age or gender was found with unilateral or global hippocampal volume. There was a correlation between episodic memory and intervention, as the intervention group showed a higher Wechsler Memory Scale-Revised Logical Memory (WMS-RLM) score (β [95% CI]: 0.326 [1.005, 6.773], p = 0.009). Furthermore, an increase in age may cause a decrease in the Mini-Mental State Examination (MMSE) score (β [95% CI]: −0.366 [−0.151, −0.034], p = 0.002). In conclusion, 3 months of aerobic dance could increase the right and total hippocampal volumes and improve episodic memory in elderly persons with aMCI.

Clinical Trial Registration: This study was registered on the Chinese Clinical Trial Registry [www.chictr.org.cn], identifier [ChiCTR-INR-15007420].

The complex burden of determining prevalence rates of mild cognitive impairment: A systematic review

Mild cognitive impairment (MCI) is a syndrome characterized by a decline in cognitive performance greater than expected for an individual's age and education level, but that does not interfere much with daily life activities. Establishing the prevalence of MCI is very important for both clinical and research fields. In fact, in a certain percentage of cases, MCI represents a prodromal condition for the development of dementia. Accordingly, it is important to identify the characteristics of MCI that allow us to predict the development of dementia. Also, initial detection of cognitive decline can allow the early implementation of prevention programs aimed at counteracting or slowing it down. To this end, it is important to have a clear picture of the prevalence of MCI and, consequently, of the diagnostic criteria used. According to these issues, this systematic review aims to analyze MCI prevalence, exploring the methods for diagnosing MCI that determine its prevalence. The review process was conducted according to the PRISMA statement. Three thousand one hundred twenty-one international articles were screened, and sixty-six were retained. In these studies, which involved 157,035 subjects, the prevalence of MCI ranged from 1.2 to 87%. The review results showed a large heterogeneity among studies due to differences in the subjects' recruitment, the diagnostic criteria, the assessed cognitive domains, and other methodological aspects that account for a higher range of MCI prevalence. This large heterogeneity prevents drawing any firm conclusion about the prevalence of MCI.