Education, Activity Engagement, and Cognitive Function in US Chinese Older Adults

Risk Polymorphisms of FNDC5, BDNF, and NTRK2 and Poor Education Interact and Aggravate Age-Related Cognitive Decline

Cognitive abilities tend to decline with aging, with variation between individuals, and many studies seek to identify genetic biomarkers that more accurately anticipate risks related to pathological aging. We investigated the influence of BDNF, NTRK2, and FNDC5 single nucleotide polymorphisms (SNPs) on the cognitive performance of young and older adults with contrasting educational backgrounds. We addressed three questions: (1) Is education associated with reduced age-related cognitive decline? (2) Does the presence of SNPs explain the variation in cognitive performance observed late in life? (3) Is education differentially associated with cognition based on the presence of BDNF, NTRK2, or FNDC5 polymorphisms? We measured the cognitive functions of young and older participants, with lower and higher education, using specific and sensitive tests of the Cambridge Automated Neuropsychological Test Assessment Battery. A three-way ANOVA revealed that SNPs were associated with differential performances in executive functions, episodic memory, sustained attention, mental and motor response speed, and visual recognition memory and that higher educational levels improved the affected cognitive functions. The results revealed that distinct SNPs affect cognition late in life differentially, suggesting their utility as potential biomarkers and emphasizing the importance of cognitive stimulation that advanced education early in life provides.

Couples' Cognition, Intimacy, and Activity Engagement: An Actor-Partner Interdependence Model Analysis

OBJECTIVES

This study examines the actor and partner effects of cognition on activity engagement and the potential mediating role of intimate relationship in older couple dyadic context.

METHODS

Data for this study were obtained from heterosexual couples who participated in the 2020 wave of the Health and Retirement Study. Constructing a dyadic model of couples' cognitions, activity engagement, and intimacy using structural equation modeling to analyze the relationship between variables and mediating effects.

RESULTS

At the actor level, cognition was positively correlated with their activity participation. At the partner level, wives' cognition and husbands' activity engagement were positively correlated. Husband's cognitive score affect wife's subjective feelings about intimacy. The mediation effect of Wife's intimacy on the relationship between husband's cognition and wife's activity engagement was significant.

CONCLUSIONS

In older couples, cognition influences activity engagement at a binary level, and this association is influenced by the level of intimacy. Improving intimacy can help increase activity engagement in older couples, which in turn promotes health. Clinical Implications Maintaining cognition helps older people enjoy good marriage and participation in activities. For women, the closer the partnership, the higher the frequency of participating in various activities.

Education, Social Engagement, and Cognitive Function: A Cross-Lagged Panel Analysis

OBJECTIVES

Although education and social engagement are considered cognitive reserves, the pathway of both reserves on cognitive function has been rarely studied. This study aimed to examine the underlying mechanism between education, social engagement, and cognitive function.

METHODS

This study used 2-wave data (2010 and 2014) from Health and Retirement Study in the United States (N = 3,201). Education was measured by years of schooling. Social engagement was evaluated by 20 items including volunteering, physical activities, social activities, and cognitive activities. Cognitive function was assessed by a modified Telephone Interview for Cognitive Status. A cross-lagged panel model was fitted to test the mediating mechanism between education, social engagement, and cognitive function.

RESULTS

Controlling for covariates, higher education in early life was associated with better cognitive function in old age (b = 0.211, 95% confidence interval [CI] = [0.163, 0.259], p < .01). Late-life social engagement partially mediated the association between education and cognitive function (indirect effect = 0.021, 95% CI = [0.010, 0.033], p < .01). The indirect path between education and social engagement via cognition also existed (b = 0.009, 95% CI = [0.005, 0.012], p < .001).

DISCUSSION

Education in earlier life stage may exert a lifelong effect on cognitive function as well as an indirect effect via enhancing late-life cognitive reserve such as social engagement. The cross-lagged effect of social engagement on cognitive function is significant and vice versa. Future research may explore other cognitive reserves over the life course and its underlying mechanism to achieve healthy cognitive aging.

Depressive Symptomatology as a Predictor of Cognitive Impairment: Evidence from the Korean Longitudinal Study of Aging (KLOSA), 2006-2020

Depressive symptoms are recognized as risk factors for cognitive impairment with intricate underlying biological mechanisms. We explored the link between depressive symptoms and cognitive impairment onset; we also assessed how this association is influenced by educational levels. This study included 5843 individuals aged ≥45 years, comprising 27,908 observations from 2006 to 2020. Based on repeated measurements of each participant, we estimated the association between depressive symptoms and cognitive impairment onset after a 2-year follow-up by using generalized estimating equations. The incidence rate was 9.4% among those individuals without depressive symptoms, which was in contrast with a rate of 21.0% among those individuals experiencing depressive symptoms. The odds ratio (OR) (95% confidence interval [CI]) for the association between depressive symptoms and cognitive impairment onset in the overall sample was 1.61 (1.47-1.76). This association was more pronounced among individuals with higher educational levels. Specifically, the OR (95% CI) of the association between depressive symptoms and cognitive impairment was highest among individuals with a college education (2.60 [1.78-3.81]), and the association was lowest among individuals with elementary or no education levels (1.45 [1.28-1.63]). Our findings highlight the idea that although individuals with higher educational backgrounds exhibit a diminished risk of cognitive impairment, the detrimental impacts of depressive symptoms on cognitive performance are particularly more pronounced within this group.

Association of Lifelong Cognitive Reserve with Dementia and Mild Cognitive Impairment among Older Adults with Limited Formal Education: A Population-Based Cohort Study

INTRODUCTION

Early-life educational attainment contributes to cognitive reserve (CR). We investigated the associations of lifelong CR with dementia and mild cognitive impairment (MCI) among older people with limited formal education.

METHODS

This population-based cohort study included 2,127 dementia-free participants (≥60 years; 59.4% women; 81.5% with no or elementary school) who were examined at baseline (August-December 2014) and follow-up (March-September 2018). Lifelong CR score at baseline was generated from six lifespan intellectual factors. Dementia, MCI, and their subtypes were defined according to the international criteria. Data were analyzed using Cox proportional-hazards models.

RESULTS

During the total of 8,330.6 person-years of follow-up, 101 persons were diagnosed with dementia, including 74 with Alzheimer's disease (AD) and 26 with vascular dementia (VaD). The high (vs. low) tertile of lifelong CR score was associated with multivariable-adjusted hazards ratios (95% confidence interval) of 0.28 (0.14-0.55) for dementia and 0.18 (0.07-0.48) for AD. The association between higher CR and reduced AD risk was significant in people aged 60-74 but not in those aged ≥75 years (p for interaction = 0.011). Similarly, among MCI-free people at baseline (n = 1,635), the high (vs. low) tertile of lifelong CR score was associated with multivariable-adjusted hazard ratios of 0.51 (0.38-0.69) for MCI and 0.46 (0.33-0.64) for amnestic MCI. Lifelong CR was not related to VaD or non-amnestic MCI.

DISCUSSION

High lifelong CR is associated with reduced risks of dementia and MCI, especially AD and amnestic MCI. It highlights the importance of lifelong CR in maintaining late-life cognitive health even among people with no or limited education.

Activity engagement and cognitive function among chinese older adults: moderating roles of gender and age

BACKGROUND

Many studies have found that engaging in activities, including physical exercise, social interaction, and cognitive training, is beneficial for preventing cognitive decline among older adults; however, the demographic differences in the association between activity engagement and cognitive functions remain understudied. This study investigates: (a) the influence of activity engagement on cognitive functions among Chinese older adults, and (b) the moderating roles of age and gender in these associations .

METHODS

The data were derived from the China Health and Retirement Longitudinal Study in 2018, which included 9803 participants aged 60 or older. A multiple regression model was used to test the study hypotheses.

RESULTS

Engaging in physical activity (b = 1.578, p < .001), social interaction (b = 1.199, p < .001), and cognitive activity (b = 1.468, p < .001) was positively associated with cognitive functions, whereas the effect of volunteer activities on cognitive functions was not significant (b = -.167, p = .390). Light- and moderate-intensity activities were beneficial for cognition (light: b = .847, p < .001; moderate: b = 1.189, p < .001), but vigorous-intensity activity was negatively related to cognition (b = -.767, p < .001). In addition, women and participants with advanced age appeared to benefit more from cognitive activities than their male and younger counterparts, respectively (gender: b = 1.217, p = .002; age: b = .086, p = .004). The adverse effects of vigorous-intensity activities (including agricultural work) on cognitive health were stronger for women and younger participants (gender: b = -1.472, p < .001; age: b = .115, p < .001). The protective effects of moderate-intensity activities on people's cognition increased with increasing age (b = .055, p = .012).

CONCLUSIONS

The findings indicate that participating in physical, social, and cognitive activities can help older adults to maintain cognitive health. They suggest that older adults should select activities while considering activity intensity and their individual characteristics.

Sex differences in cognitive aging and the role of socioeconomic status: Evidence from multi-cohort studies

BACKGROUND

Sex differences exist in cognitive function, and socioeconomic status (SES) may play a role in changing these discrepancies. This study investigated the role of SES in contributing to sex differences in cognitive function.

METHODS

We conducted a pooled multi-cohort study on the basis of four comparative cohort studies from the UK, the US, Europe and China to assess sex differences and the role of SES in cognitive decline by birth cohort (1930-1938, 1939-1945, 1946-1968). Cognitive function was measured in three domains based on the mean and SD of the corresponding tests: episodic memory, working memory, and time orientation. SES was the summed scores of education and household wealth.

FINDINGS

61,019 individuals were involved. Cognitive function of women declined faster than those of men as growing old (particularly after 80 years old). As SES increased, cognitive function increased more for women than for men in most cases among later-born cohorts (1930-1938, 1939-1945, 1946-1968) (e.g., episodic memory scores at 60 years old: women exhibited an increase from -0.09 [95%CI -0.12, -0.07] in low SES to 0.89 [0.86, 0.92] in high SES; men from -0.16 [-0.19, -0.14] to 0.59 [0.56, 0.62]). However, sex-specific cognitive benefits were absent in the oldest birth cohort (1895-1929).

INTERPRETATION

These findings highlight the importance of considering the role of SES in the discrepancy of sex difference in cognitive aging.

Leisure activities and cognitive impairment in old age: The role of life course socioeconomic status

In the current literature on cognitive function, life course socioeconomic status (SES) and engaging in leisure activities are often viewed as parallel measures of cognitive reserve that independently affect cognitive impairment in old age. Some studies also suggest that leisure activity mediates the effect of SES on cognitive impairment. What is less examined is the modification effect of SES on the association between engaging in leisure activities and cognitive impairment, especially from a life course perspective. In this study, we focus on the interaction effects of specific measures of SES and leisure activities on cognitive impairment. We use data from the Chinese Longitudinal Healthy Longevity Survey, which includes five waves of interviews with adults aged 65 and older between 2002 and 2014. Cognitive impairment is measured by the Chinese version of the Mini-Mental Status Examination. Childhood and adulthood SES and participation in seven leisure activities are included in this analysis. We adopt a lagged independent variable approach and the Generalized Linear Mixed Model to conduct the analysis. Findings confirm that higher SES in both childhood and adulthood are associated with low levels of cognitive impairment in the older Chinese population. Furthermore, there are significant interaction effects between specific life course SES and leisure activities with a consistent pattern: Those of higher life course SES enjoy extra benefits from engaging in leisure activities. The findings point to a modification mechanism that connects life course SES, leisure activities, and cognitive health inequality among older adults.

Lifelong Cognitive Reserve, Imaging Markers of Brain Aging, and Cognitive Function in Dementia-Free Rural Older Adults: A Population-Based Study

BACKGROUND

Cognitive reserve (CR) partly explains cognitive variability in the presence of pathological brain aging.

OBJECTIVE

We investigated the interplay of lifelong CR with age, sex, and brain aging markers in cognitive phenotypes among older adults with very limited education.

METHODS

This population-based cross-sectional study included 179 dementia-free participants (age ≥65 years; 39.7% women; 67.0% had no or elementary education) examined in 2014-2016. We assessed lacunes and volumes of hippocampus, ventricles, grey matter, white matter (WM), and white matter hyperintensities. Lifelong CR score was generated from six lifespan intellectual factors (e.g., education and social support). We used Mini-Mental State Examination (MMSE) score to assess cognition and Petersen's criteria to define mild cognitive impairment (MCI). Data were analyzed using general linear and logistic models.

RESULTS

The association of higher lifelong CR score (range: -4.0-5.0) with higher MMSE score was stronger in women (multivariable-adjusted β-coefficient and 95% CI: 1.75;0.99-2.51) than in men (0.68;0.33-1.03) (pinteraction = 0.006). The association of higher CR with MCI (multivariable-adjusted odds ratio and 95% CI: 0.77;0.60-0.99) did not vary by age or sex. Among participants with low CR (<1.4[median]), greater hippocampal and WM volumes were related to higher MMSE scores with multivariable-adjusted β-coefficients being 1.77(0.41-3.13) and 0.44(0.15-0.74); the corresponding figures in those with high CR were 0.15(-0.76-1.07) and -0.17(-0.41-0.07) (pinteraction <0.01). There was no statistical interaction of CR with MRI markers on MCI.

CONCLUSION

Greater lifelong CR capacity is associated with better late-life cognition among people with limited education, possibly by compensating for impact of neurodegeneration.

Cognitive Reserve and Cognitive Functioning among Oldest Old Adults: Findings from the Georgia Centenarian Study

OBJECTIVES

Living a long life does not guarantee the maintenance of optimal cognitive functioning; however, similar to older adults in general, cognitive reserve may also protect oldest-old adults from cognitive decline. The purpose of this study was to assess cognitive reserve among centenarians and octogenarians and to evaluate a process model of cognitive reserve.

METHODS

A total of 321 centenarians and octogenarians from the Georgia Centenarian Study were included in this study. Cognitive reserve components included level of education, occupational responsibility, current social engagement, past engaged lifestyle, and activity. Cognitive functioning was measured with the Mini-Mental Status Examination.

RESULTS

Structural equation modeling was computed, and the overall model fit well, χ2 (df = 3) = 5.02, p = .17; CFI = .99, RMSEA = .05. Education is directly and indirectly related to cognitive functioning through occupational responsibility and past engaged lifestyle. Current social engagement is related to cognitive functioning directly and indirectly through current activities. The four direct predictors (i.e., education, current social engagement, current activity, and past engaged lifestyle) explained 35% of the variance in cognitive functioning.

CONCLUSION

The results provide important information for cognitive reserve theories with implications for interventions that build cognitive reserve.

Acculturation and Subsequent Oral Health Problems Among Foreign-Born Older Chinese Americans: Does Neighborhood Disorder Matter?

OBJECTIVES

To investigate the relationship between acculturation and subsequent oral health problems in older Chinese Americans and to further test the moderating role of neighborhood disorder in such a relationship.

METHODS

The working sample included 2,706 foreign-born community-dwelling older Chinese Americans aged 60 years or older who participated in the Population Study of Chinese Elderly in Chicago at baseline between 2011 and 2013 and the 2-year follow-up between 2013 and 2015. Stepwise Poisson regressions with lagged dependent variable were conducted.

RESULTS

Behavioral acculturation was protective against subsequent oral health problems, and the protective role was stronger among individuals reporting lower levels of neighborhood disorder. Residence in Chinatown was associated with an increase in the risk of subsequent oral health problems.

DISCUSSION

To reduce oral health symptoms and related burdens, it is important to consider, in practice and policy, the role of acculturation and the neighborhood on subsequent oral health outcomes.

Cognitive Reserve, Leisure Activity, and Neuropsychological Profile in the Early Stage of Cognitive Decline

In older adults with normal cognition, cognitive reserve (CR) is known to be associated with the neuropsychological profile. We investigated the association between comprehensive CR and detailed neuropsychological profile in the early stage of cognitive decline. Fifty-five participants with mild cognitive impairment or subjective cognitive decline completed the cognitive reserve index questionnaire (CRIq) that yielded total, education, working activity, and leisure time scores (CRI-Total, CRI-Education, CRI-Working activity, and CRI-Leisure time, respectively). Mini-mental state examination (MMSE) and detailed neuropsychological evaluation were performed. Psychiatric symptom scales were applied to measure depression, apathy, positive or negative affect, and quality of life. Correlation and linear regression analyses of the variables were performed. The effect of CR-Education, CRI-Working activity, and CRI-Leisure time on the composite cognitive score was determined using a multivariable regression model. We observed that for CRI-Total (B = 3.00, p = 0.005), CRI-Education (B = 3.39, p = 0.002), and CRI-Leisure time (B = 2.56, p = 0.015), CR correlated with MMSE scores, while only CRI-Leisure time associated with the naming ability (B = 2.20, p = 0.033) in the detailed neuropsychological test results of the participants. Multivariable regression model also indicated that among CRI subscores, CRI-Leisure time directly affects the composite cognitive score (β = 0.32, p = 0.011). We found that in the early stage of cognitive decline in older adults, comprehensive CR was associated with global cognition, and only leisure activity was identified to be associated with the detailed neuropsychological profile including naming ability. These results may imply the positive effect of leisure activity on cognitive function in the early stages of cognitive decline.

Reliability and concurrent validity of Alzheimer's disease assessment scale - Cognitive subscale, Chinese version (ADAS-Cog-C) among Chinese community-dwelling older people population

OBJECTIVE

To evaluate reliability and concurrent validity of the Alzheimer's Disease Assessment Scale - Cognitive Subscale, Chinese Version (ADAS-Cog-C) among Chinese community older adults.

METHOD

Three groups, comprising of 1,276 community-dwelling older adults, were included in this study: a normal control (NC), a mild cognitive impairment (MCI), and an Alzheimer's disease (AD) group. All participants were assessed through ADAS-Cog-C, clinical interviews, physical examinations, Mini Mental State Examination (MMSE), and the Clinical Dementia Rating Scale (CDR). Internal consistency was assessed to evaluate the reliability of ADAS-Cog-C. Pearson and Spearman correlation coefficients were calculated to evaluate the concurrent validity between ADAS-Cog-C, MMSE, and CDR.

RESULTS

Overall, the Cronbach's alpha coefficients of ADAS-Cog-C for the AD and MCI groups were 0.843 and 0.554, respectively. The split-half reliability coefficients for the AD and MCI groups were 0.860 and 0.539, respectively. ADAS-Cog-C scores were negatively correlated with MMSE scores (r = -0.706, p < 0.001) and positively associated with CDR scores (r = 0.546, p < 0.001). After excluding the MCI group from the analysis, the internal consistency of ADAS-Cog-C for the total population improved (α = 0.813, r _hh = 0.852, all p < 0.001), as did the correlation between ADAS-Cog-C and MMSE (r = -0.828, p < 0.001) and CDR (r = 0.429, all p < 0.001) scores.

CONCLUSIONS

ADAS-Cog-C has good internal consistency and concurrent validity for assessing Chinese community older adults with AD, but poor consistency, good concurrent validity with the MMSE while moderate concurrent validity with the CDR for MCI.

Changes in Resting-State Cerebral Activity in Women With Polycystic Ovary Syndrome: A Functional MR Imaging Study

BACKGROUND

Previous studies have found that women with polycystic ovary syndrome (PCOS) have some degree of brain function change as well as cognitive function and emotions, such as poor executive functioning and memory, anxiety and depressive symptoms. However, the neurobiological mechanisms underlying these alterations have not yet been clarified.

METHOD

Fasting serum hormone testing, neuropsychological testing and resting-state magnetic resonance imaging (rs-fMRI) were performed in 41 women with newly diagnosed PCOS and 41 healthy controls matched by age and education during their 2-5 days of menstrual period. Analysis of the amplitude of low-frequency fluctuation (ALFF) was used to calculate the seed points. Then, the functional connectivity (FC) values between these abnormal seed points and other voxels in the whole brain were calculated. Finally, the correlations among clinical indexes, neuropsychological evaluation scores, and neuroimaging data were analyzed.

RESULTS

Compared with the control group, the PCOS group showed higher luteinizing hormone (LH) and serum insulin levels, worse sleep quality, increased depressive and anxiety state scores, and memory and executive function impairments. Pearson's correlation analysis showed that the decreased ALFF value in the left middle frontal gyrus (MFG.L), which is related to poor executive performance and depressive disorders, was negatively correlated with the plasma insulin level in subjects with insulin resistance. Furthermore, the increased FC strength between the MFG.L and left inferior frontal gyrus (IFG.L) was positively correlated with the serum testosterone level. The enhanced FC strength between the left posterior cingulate gyrus (PCG.L) and triangular part of the left inferior frontal gyrus (IFGtriang.L) was negatively correlated with the plasma LH level. When use the right middle occipital gyrus (MOG.R) as the seed point, the FC strength with the right inferior occipital gyrus (IOG.R), which is associated with impaired memory, was decreased.

CONCLUSION

The ALFF and FC results elucidated brain functional abnormalities at the regional and network levels in women with PCOS, while correlation analyses simultaneously demonstrated that these alterations were associated with serum hormones and cognitive function. These results may provide useful information regarding the potential mechanisms of cognitive impairment and emotional changes in this population.