Social Health and Cognitive Change in Old Age: Role of Brain Reserve

The effect of social exclusion on the cognitive health of middle-aged and older adults: A systematic review

This systematic review aimed to evaluate the independent and joint effects of social exclusion in three specific domains-economic, social relations, and civic participation-on the cognitive health of middle-aged and older adults. Longitudinal studies from January 2000 to October 2023 were identified via Web of Science, Scopus, and PubMed, with sixty-five studies meeting inclusion criteria. The quality of the studies was assessed with Newcastle-Otawa Scale. Analysis revealed a strong association between economic exclusion and cognitive decline, with most studies indicating a significant negative impact. Ten studies found a positive link between volunteering and cognitive health for civic participation, while eight did not, showing mixed evidence. In social relations, most studies connected loneliness, social isolation, smaller social networks, reduced contact with family and friends, lower engagement in activities, and negative social interactions with cognitive decline. Notably, one study found that older adults experiencing social exclusion in multiple domains simultaneously face even greater cognitive decline. In summary, this review shows that social exclusion in economic, social relations, and civic participation and all together domains is associated with greater cognitive decline in older adults.

Social frailty and its association with cognitive trajectories in older adults: a prospective cohort study

BACKGROUND

Social frailty, a multidimensional construct encompassing various social behaviors, resources, and needs, significantly impacts cognitive health in older adults. Despite existing studies linking specific social factors to cognitive function, the association between social frailty and long-term cognitive trajectories remains underexplored. This study aims to evaluate the longitudinal association between social frailty and trajectory of cognitive function in dementia-free older adults.

METHODS

This prospective cohort study used data from the National Health and Aging Trends Study (NHATS). Social frailty was assessed using the Makizako Social Frailty Index. According to the presence of social components, individuals were categorized into social frailty (≥ 2), pre-social frailty (1), and robust (0), respectively. Cognitive function was annually evaluated through memory, orientation, and executive function tests from 2011 to 2018. Mixed-effects linear models were employed to assess the associations between social frailty and changes in global and domain-specific cognitive function, adjusting for relevant covariates.

RESULTS

In this study, 4956 dementia-free older adults (mean age 76.57 [7.41]) with complete at least 2 times of cognitive tests were included. Compared with the robust, social frailty was associated with significantly faster decline in global cognitive function (β = -0.041, 95% CI [-0.047, -0.036] z score per year) and domain-specific cognitive function (βmemory = -0.045, 95% CI [-0.055, -0.036] z score per year; βorientation = -0.027, 95% CI [-0.034, -0.020] z score per year; βexecutive = -0.042, 95% CI [-0.053, -0.032] z score per year) over the follow-up. Additionally, pre social frailty was associated with significantly faster decline in global cognitive function (β = -0.016, 95% CI [-0.021, -0.012] z score per year), memory function (β= -0.045, 95% CI [-0.055, -0.036] z score per year), and orientation function (β= -0.027, 95% CI [-0.034, -0.020] z score per year) over the follow-up.

CONCLUSIONS

Social frailty is associated with faster decline in cognition in older adults, underscoring the necessity for enhanced social support and engagement to mitigate cognitive deterioration in vulnerable populations.

Optimising an immersive virtual reality behaviour change intervention to support retired and non-working adults to reduce their sedentary behaviour: a mini-focus group interview study

OBJECTIVE

Prolonged sedentary behaviour is associated with numerous negative health outcomes. Immersive virtual reality (IVR) offers opportunities for retired and non-working adults to take part in meaningful non-sedentary activities that may not be available to them in their natural environment. Using the behaviour change wheel and theoretical domains framework, an IVR intervention prototype was developed. This study aimed to explore and optimise the prototype with retired and non-working adults. A secondary aim was to explore participants' perceptions of IVR more generally.

METHODS AND MEASURES

Five semi-structured mini-focus group interviews were conducted with 12 retired and non-working adults. Each group explored the intervention prototype together and discussed their experiences afterwards. A rapid analysis and reflexive thematic analysis (TA) were conducted on the data.

RESULTS

Several feasible intervention design changes were generated through the rapid analysis. The reflexive TA generated three themes relating to participants' past experiences reducing their time spent sedentary, how they experienced the intervention prototype as a means to reduce their time spent sedentary, and their perspectives on using such an intervention in the future.

CONCLUSION

The results indicate that retired and non-working adults may enjoy using IVR to reduce sedentary time but generally favour natural experiences when possible.

Social health markers in the context of cognitive decline and dementia: an international qualitative study

Background

Social health in the context of dementia has recently gained interest. The development of a social health conceptual framework at the individual and social environmental levels, has revealed a critical need for a further exploration of social health markers that can be used in the development of dementia intervention and to construct social health measures.

Objective

To identify social health markers in the context of dementia.

Method

This international qualitative study included six countries: Australia, Germany, Indonesia, Italy, Poland, and the Netherlands. Using purposive sampling, three to five cases per country were recruited to the study, with each case consisting of a person living with dementia, a primary informal caregiver, an active network member, and a health care professional involved in the care of the person with dementia. In-depth interviews, using an agreed topic guide, and content analysis were conducted to identify known and new social health markers. The codes were then categorized against our conceptual framework of social health.

Results

Sixty-seven participants were interviewed. We identified various social health markers, ranging from those that are commonly used in epidemiological studies such as loneliness to novel markers of social health at the individual and the social environmental level. Examples of novel individual-level markers were efforts to comply with social norms and making own choices in, for example, keeping contact or refusing support. At a social environmental level, examples of novel markers were proximity (physical distance) and the function of the social network of helping the person maintaining dignity.

Conclusions

The current study identified both well-known and novel social health markers in the context of dementia, mapped to the social health framework we developed. Future research should focus on translating these markers into validated measures and on developing social health focused interventions for persons with dementia.

Association of social health with all-cause mortality and cause-specific mortality: A population-based cohort study

BACKGROUND

Previous studies only focused on the individual social factors, without considering the overall social health patterns. The present study aimed to develop an integrated social health score (SHS) and investigate its associations with all-cause, cardiovascular disease (CVD), cancer mortality.

METHODS

A total of 330,716 participants (mean age 56.3 years; 52.4 % female) from UK Biobank was included between 2006 and 2010, and thereafter followed up to 2021. SHS was calculated by using information on social connections, social engagement and social support. Cox proportional hazards models was used to estimate the hazard ratios and 95 % confidence intervals (CIs) of the association between SHS and all-cause and cause-specific mortality and the 4-way decomposition was used to quantify the mediating effect of lifestyle factors.

RESULTS

During a median follow-up period of 12.4 years, 37,897 death cases were recorded, including 4347 CVD and 10,380 cancer cases. The SHS was inversely associated with the risks of all-cause, CVD and cancer mortality in a dose-dependent manner (P for trend <0.001). The association between SHS with all-cause mortality was mediated by lifestyle factors including diet score, smoking status and alcohol consumption.

CONCLUSION

Integrated SHS was inversely associated with risks of all-cause, CVD and cancer mortality, and the associations were partially mediated by lifestyle factors. Our study highlights the importance of maintaining high levels of social health by jointly enhancing social involvement, expanding social networks, and cultivating enduring intimate relationships across the life course.

High cognitive reserve attenuates the risk of dementia associated with cardiometabolic diseases

BACKGROUND

Cardiometabolic diseases (CMDs) including type 2 diabetes, heart disease, and stroke have been linked to a higher risk of dementia. We examined whether high levels of cognitive reserve (CR) can attenuate the increased dementia risk and brain pathologies associated with CMDs.

METHODS

Within the UK Biobank, 216,178 dementia-free participants aged ≥ 60 were followed for up to 15 years. Baseline CMDs and incident dementia were ascertained from medical records, medication use, and medical history. Latent class analysis was used to generate an indicator of CR (low, moderate, and high) based on education, occupational attainment, confiding in others, social contact, leisure activities, and television watching time. A subsample (n = 13,663) underwent brain MRI scans during follow-up. Volumes of total gray matter (GMV), hippocampus (HV), and white matter hyperintensities (WMHV) were ascertained, as well as mean diffusivity (MD) and fractional anisotropy (FA) in white matter tracts.

RESULTS

At baseline, 43,402 (20.1%) participants had at least one CMD. Over a mean follow-up of 11.7 years, 6,600 (3.1%) developed dementia. The presence of CMDs was associated with 57% increased risk of dementia (HR 1.57 [95% CI 1.48, 1.67]). In joint effect analysis, the HRs of dementia for people with CMDs and moderate-to-high CR and low CR were 1.78 [1.66, 1.91] and 2.13 [1.97, 2.30]), respectively (reference: CMD-free, moderate-to-high CR). Dementia risk was 17% lower (HR 0.83 [0.77, 0.91], p < 0.001) among people with CMDs and moderate-to-high compared to low CR. On brain MRI, CMDs were associated with smaller GMV (β -0.18 [-0.22, -0.13]) and HV (β -0.13 [-0.18, -0.08]) as well as significantly larger WMHV (β 0.06 [0.02, 0.11]) and MD (β 0.08 [0.02, 0.13]). People with CMDs and moderate-to-high compared to low CR had significantly larger GMV and HV, but no differences in WMHV, MD, or FA.

CONCLUSIONS

Among people with CMDs, having a higher level of CR was associated with lower dementia risk and larger gray matter and hippocampal volumes. The results highlight a mentally and socially active life as a modifiable factor that may support cognitive and brain health among people with CMDs.

Cognitive reserve, cortisol, and Alzheimer's disease biomarkers: A memory clinic study

INTRODUCTION

Cognitive reserve might mitigate the risk of Alzheimer's dementia among memory clinic patients. No study has examined the potential modifying role of stress on this relation.

METHODS

We examined cross-sectional associations of the cognitive reserve index (CRI; education, occupational complexity, physical and leisure activities, and social health) with cognitive performance and AD-related biomarkers among 113 memory clinic patients. The longitudinal association between CRI and cognition over a 3-year follow-up was assessed. We examined whether associations were influenced by perceived stress and five measures of diurnal salivary cortisol.

RESULTS

Higher CRI scores were associated with better cognition. Adjusting for cortisol measures reduced the beneficial association of CRI on cognition. A higher CRI score was associated with better working memory in individuals with higher (favorable) cortisol AM/PM ratio, but not among individuals with low cortisol AM/PM ratio. No association was found between CRI and AD-related biomarkers.

DISCUSSION

Physiological stress reduces the neurocognitive benefits of cognitive reserve among memory clinic patients.

HIGHLIGHTS

Physiological stress may reduce the neurocognitive benefits accrued from cognitively stimulating and enriching life experiences (cognitive reserve [CR]) in memory clinic patients. Cortisol awakening response modified the relation between CR and P-tau181, a marker of Alzheimer's disease (AD). Effective stress management techniques for AD and related dementia prevention are warranted.

Associations between social health factors, cognitive activity and neurostructural markers for brain health - A systematic literature review and meta-analysis

Social health factors (e.g., social activities or social support) and cognitive activity engagement have been associated with dementia risk, but their neural substrates have not been well established. This systematic review and meta-analysis summarizes the available evidence regarding the association between these factors and cerebral macro- and micro-structure. A comprehensive literature search was conducted in various databases, following predefined criteria. Heterogeneity, risk of publication bias and overall certainty of evidence were assessed using standardized scales and, whenever appropriate, random effects meta-analysis was conducted. Of 6715 identified articles, 43 were included. Overall, consistency of findings was low and methodological heterogeneity high for all outcomes. However, in some studies cognitive and social activities were positively associated with total brain, global and cortical grey matter and hippocampal volume as well as white matter microstructural integrity. Furthermore, structural social network characteristics (e.g., social network size) were associated with regional grey matter volumes, while functional social network characteristics (e.g., social support) were additionally associated with total brain volume. Meta-analyses revealed small but significant partial correlations between cognitive and social activities and hippocampal (three studies; n = 892; rz =0.07) and white matter hyperintensity volume (three studies; n = 2934; rz =-0.04). More prospective studies are needed to assess temporal associations.

Social Health and Change in Cognitive Capability among Older Adults: Findings from Four European Longitudinal Studies

INTRODUCTION

In this study, we examine whether social health markers measured at baseline are associated with differences in cognitive capability and the rate of cognitive decline over an 11-to-18-year period among older adults and compare results across studies.

METHODS

We applied an integrated data analysis approach to 16,858 participants (mean age 65 years; 56% female) from the National Survey for Health and Development (NSHD), the English Longitudinal Study of Aging (ELSA), the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K), and the Rotterdam Study. We used multilevel models to examine social health in relation to cognitive capability and the rate of cognitive decline.

RESULTS

Pooled estimates show distinct relationships between markers of social health and cognitive domains, e.g., a large network size (≥6 people vs. none) was associated with higher executive function (0.17 standard deviation [SD] [95% CI: 0.00, 0.34], I2 = 27%) but not with memory (0.08 SD [95% CI: -0.02, 0.18], I2 = 19%). We also observed pooled associations between being married or cohabiting, having a large network size, and participating in social activities with slower decline in cognitive capability. However, estimates were close to zero, e.g., 0.01 SD/year (95% CI: 0.01, 0.02) I2 = 19% for marital status and executive function. There were clear study-specific differences: results for average processing speed were the most homogenous, and results for average memory were the most heterogeneous.

CONCLUSION

Overall, markers of good social health have a positive association with cognitive capability. However, we found differential associations between specific markers of social health and cognitive domains and differences between studies. These findings highlight the importance of examining between-study differences and considering the context specificity of findings in developing and deploying interventions.

EngAge - A metacognitive intervention to supplement working memory training: A feasibility study in older adults

Working Memory (WM) training has shown promise in supporting cognitive functioning in older adult populations, but effects that generalize beyond the trained task have been inconsistent. Targeting cognitive processes in isolation might be a limiting factor given that metacognitive and motivational factors have been shown to impact older adults' engagement with challenging cognitive activities, such as WM training. The current feasibility study implemented a novel metacognitive intervention in conjunction with WM training in older adults and examined its potential amplifying short- and long-term effects on cognitive and self-report outcomes as compared to WM or active control training alone. One-hundred and nineteen older adults completed a cognitive training over the course of 20 sessions at home. The cognitive training targeted either WM or general knowledge. In addition, one of the WM training groups completed a metacognitive program via group seminars. We tested for group differences in WM, inhibitory control, and episodic memory, and we assessed participants' perceived self-efficacy and everyday memory failures. At post-test, we replicated earlier work by demonstrating that participants who completed the WM intervention outperformed the active control group in non-trained WM measures, and to some extent, in inhibitory control. However, we found no evidence that the supplemental metacognitive program led to benefits over and above the WM intervention. Nonetheless, we conclude that our metacognitive program is a step in the right direction given the tentative long-term effects and participants' positive feedback, but more longitudinal data with larger sample sizes are needed to confirm these early findings.