Negative and Positive Psychosocial Factors in Relation to Cognitive Health in Older African Americans

Does the coexistence of pain and depressive symptoms accelerate cognitive decline?

OBJECTIVES

Investigate whether the coexistence of pain and depressive symptoms is a risk factor for cognitive decline in individuals aged 50 or older.

METHOD

Longitudinal trajectory study involving 4,718 participants from the English Longitudinal Study of Ageing (ELSA). Joint pain was self-reported, and intensity was classified as mild, moderate/intense. Depressive symptoms were investigated using the Centre for Epidemiologic Studies Depression Scale (CES-D-8 ≥ 4). The sample was divided into six groups: no pain and no depression (NP/NDe), mild pain and no depression (MP/NDe), moderate/intense pain and no depression (M-IP/NDe), no pain and depression (NP/De), mild pain and depression (MP/De), and moderate/intense pain and depression (M-IP/De). The outcome of interest was performance in memory, executive function, and global cognition. Generalised linear mixed models were used to analyse performance in the cognitive domains and global cognition score as a function of pain and depressive symptoms during 12 years of follow-up.

RESULTS

Over time, individuals with M-IP/De had a greater memory decline (-0.038 SD/year, 95%CI: -0.068 to -0.007) and the global cognition score (-0.033 SD/year, 95%CI: -0.063 to -0.002) than those with NP/NDe.

CONCLUSION

The coexistence of moderate/intense pain and depressive symptoms is a risk factor for the decline of global cognition and memory.

Purpose in life and cognitive health: a 28-year prospective study

OBJECTIVES

To examine the prospective association between purpose in life measured at three points across middle and older adulthood and cognitive outcomes assessed 8-28 years later.

DESIGN

Prospective Study.

SETTING

Wisconsin Longitudinal Study of Aging (WLS).

PARTICIPANTS

WLS participants who reported on their purpose in life at Round 4 (1992-1994; Mage = 52.58), Round 5 (2003-2007; Mage = 63.74), and/or Round 6 (2010-2012; Mage = 70.25) and were administered a cognitive battery at Round 7 (2020; Mage = 79.94) were included in the analysis (N = 4,632).

MEASUREMENTS

Participants completed the Ryff measure of purpose in life and were administered the telephone interview for cognitive status and measures of verbal fluency, digit ordering, and numeric reasoning.

RESULTS

Purpose in life measured at age 52 was related to better global cognitive function and verbal fluency but unrelated to dementia at age 80. In contrast, purpose in life at ages 63-70 was associated with lower likelihood of dementia, as well as better global cognitive function and verbal fluency at age 80. The effect sizes were modest (median Beta coefficient = .05; median odds ratio = .85). A slightly steeper decline in purpose in life between ages 52 and 70 was found for individuals with dementia at age 80.

CONCLUSIONS

Purpose in life is associated with healthier cognitive function measured up to 28 years later. Individuals with lower purpose, especially in their 60s or older, and with steeper declines in purpose, are more likely to have dementia at age 80.

Psychological well-being trajectories preceding incident mild cognitive impairment and dementia

BACKGROUND

Poorer psychological well-being has been related to an increased dementia risk, but changes in psychological well-being along the dementia course are unclear. We explored psychological well-being trajectories before and after the diagnosis of mild cognitive impairment (MCI) and dementia.

METHODS

Within the Rush Memory and Aging Project, 910 cognitively intact older adults were followed annually for up to 14 years to detect incident MCI and dementia. Psychological well-being and its six components (self-acceptance, autonomy, environmental mastery, purpose in life, positive relation with others, and personal growth) were annually measured based on Ryff's Scales of Psychological Well-Being. Data were analysed using mixed-effect models with a backward timescale.

RESULTS

Compared with participants who remained cognitively intact, those who developed incident MCI had a faster decline in psychological well-being (β -0.015, 95% CI -0.027 to -0.003), leading to lower well-being 2 years before MCI diagnosis (mean difference at year -2, -0.099, 95% CI -0.187 to -0.012). Considering different well-being components, those who developed MCI had lower levels of purpose in life and personal growth beginning 3 years (-0.126, 95% CI -0.251 to -0.001) and 6 years (-0.139, 95% CI -0.268 to -0.009) before MCI, respectively. The slope of psychological well-being decline was similar before and after MCI diagnosis for each component except for positive relation with others, which had an accelerated decline after MCI (β -0.042, 95% CI-0.075 to -0.009). Well-being trajectories remained similar for individuals with MCI regardless of whether they later developed dementia.

CONCLUSIONS

Psychological well-being (specifically purpose in life and personal growth) became significantly lower before MCI diagnosis.

Fulfilled Mind, Healthy Gut? Relationships of Eudaimonic Psychological Well-Being With the Gut Microbiome in Postmenopausal Women

OBJECTIVE

Eudaimonic facets of psychological well-being (PWB), like purpose in life and sense of mastery, are associated with healthy aging. Variation in the gut microbiome may be one pathway by which mental health influences age-related health outcomes. However, associations between eudaimonic PWB and the gut microbiome are understudied. We examined whether purpose in life and sense of mastery, separately, were associated with features of the gut microbiome in older women.

METHODS

Participants were from the Mind-Body Study ( N = 206, mean age = 61 years), a substudy of the Nurses' Health Study II cohort. In 2013, participants completed the Life Engagement Test and the Pearlin Mastery Scale. Three months later, up to two pairs of stool samples were collected, 6 months apart. Covariates included sociodemographics, depression, health status, and health behaviors. Analyses examined associations of PWB with gut microbiome taxonomic diversity, overall community structure, and specific species/pathways. To account for multiple testing, statistical significance was established using Benjamini-Hochberg adjusted p values (i.e., q values ≤0.25).

RESULTS

We found no evidence of an association between PWB and gut microbiome alpha diversity. In multivariate analysis, higher purpose levels were significantly associated with lower abundance of species previously linked with poorer health outcomes, notably Blautia hydrogenotrophica and Eubacterium ventriosum ( q values ≤0.25). No significant associations were found between PWB and metabolic pathways.

CONCLUSIONS

These findings offer early evidence suggesting that eudaimonic PWB is linked with variation in the gut microbiome, and this might be one pathway by which PWB promotes healthy aging.

Depression, Vascular Burden, and Dementia Prevalence in Late Middle-Aged and Older Black Adults

OBJECTIVES

Late-life depression and white matter hyperintensities (WMH) have been linked to increased dementia risk. However, there is a dearth of literature examining these relationships in Black adults. We investigated whether depression or WMH volume are associated with a higher likelihood of dementia diagnosis in a sample of late middle-aged to older Black adults, and whether dementia prevalence is highest in individuals with both depression and higher WMH volume.

METHODS

Secondary data analysis involved 443 Black participants aged 55+ with brain imaging within 1 year of baseline visit in the National Alzheimer's Coordinating Center Uniform Data Set. Chi-square analyses and logistic regression models controlling for demographic variables examined whether active depression in the past 2 years, WMH volume, or their combination were associated with higher odds of all-cause dementia.

RESULTS

Depression and higher WMH volume were associated with a higher prevalence of dementia. These associations remained after controlling for demographic factors, as well as vascular disease burden. Dementia risk was highest in the depression/high WMH volume group compared to the depression-only group, high WMH volume-only group, and the no depression/low WMH volume group. Post hoc analyses comparing the Black sample to a demographically matched non-Hispanic White sample showed associations of depression and the combination of depression and higher WMH burden with dementia were greater in Black compared to non-Hispanic White individuals.

DISCUSSION

Results suggest late-life depression and WMH have independent and joint relationships with dementia and that Black individuals may be particularly at risk due to these factors.

Purpose in life and cognitive performance and informant ratings of cognitive decline, affect, and activities

OBJECTIVE

To examine (1) the association between purpose in life and multiple domains of cognitive function and informant-rated cognitive decline, affect, and activities; (2) whether these associations are moderated by sociodemographic factors, cognitive impairment, or depression; (3) whether the associations are independent of other aspects of well-being and depressive symptoms.

METHOD

As part of the 2016 Harmonized Cognitive Assessment Protocol from the Health and Retirement Study, participants completed a battery of cognitive tests and nominated a knowledgeable informant to rate their cognitive decline, affect, and activities. Participants with information available on their purpose in life from the 2014/2016 Leave Behind Questionnaire were included in the analytic sample (N = 2,812).

RESULTS

Purpose in life was associated with better performance in every cognitive domain examined (episodic memory, speed-attention, visuospatial skills, language, numeric reasoning; median β =.10, p <.001; median d =.53). Purpose was likewise associated with informant-rated cognitive decline and informant-rated affective and activity profiles beneficial for cognitive health (median β =.18, p < .001; median d =.55). There was little evidence of moderation by sociodemographic or other factors (e.g., depression). Life satisfaction, optimism, positive affect, and mastery were generally associated with cognition. When tested simultaneously with each other and depressive symptoms, most dimensions were reduced to non-significance; purpose remained a significant predictor.

CONCLUSIONS

Purpose in life is associated with better performance across numerous domains of cognition and with emotional and behavioral patterns beneficial for cognitive health that are observable by knowledgeable others. These associations largely generalize across demographic and clinical groups and are independent of other aspects of well-being.

Psychosocial factors associated with 7-year change in cognition among middle-aged and older Hispanics/Latinos: The Hispanic Community Health Study/Study of Latinos-Investigation of Neurocognitive Aging (SOL-INCA) and Sociocultural ancillary studies

INTRODUCTION

Few studies have examined the associations of psychosocial factors with cognitive change in Hispanics/Latinos.

METHODS

Data from the Hispanic Community Health Study/Study of Latinos-Investigation of Neurocognitive Aging (HCHS/SOL INCA) and Sociocultural studies were used (n = 2,155; ages ≥45 years). Psychosocial exposures included intrapersonal (ethnic identity, optimism, purpose in life), interpersonal (family cohesion, familism, social networks, social support), and social factors (ethnic discrimination, loneliness, subjective social status). Survey-linear regression models examined associations between psychosocial exposures and 7-year cognitive change (global cognition [GC], verbal learning, memory, word fluency [WF], and digit symbol substitution [DSS]).

RESULTS

Familism predicted decline in GC, verbal learning, and memory; family cohesion predicted DSS decline; and loneliness predicted memory decline. Ethnic identity was protective against decline in GC and memory, optimism and social support were protective against decline in memory, and purpose in life was protective against WF decline.

DISCUSSION

Psychosocial factors are differentially related to cognitive changes. Culturally relevant factors should be explored in Hispanic/Latino cognitive aging research.

HIGHLIGHTS

Psychosocial factors are differentially related to cognitive changes in Latinos. Role of culturally relevant factors on cognition should be further explored. Familism predicted decline in global cognition, verbal learning, and memory. Ethnic identity predicted increase in global cognition and memory.

Well-Being as a Protective Factor Against Cognitive Decline and Dementia: A Review of the Literature and Directions for Future Research

OBJECTIVES

Treatments that target the biological causes of dementia remain limited, making prevention critically important. Well-being-defined broadly as living in accordance with one's potential and experiencing one's life as enjoyable and satisfying-is a promising avenue for prevention. It can be targeted by large-scale, noninvasive interventions and has been linked with better cognitive health and lower dementia risk. In the current review, we begin by summarizing empirical evidence linking well-being to cognitive functioning, cognitive decline, dementia diagnosis, and dementia-related neuropathology. Then, we highlight 3 key areas for future research.

METHODS

We searched the literature on wellbeing, cognitive decline, and dementia, focusing on prospective and longitidinal evidence.

RESULTS

The research reviewed here provides consistent evidence for associations of well-being with cognitive decline, dementia risk, and cognitive resilience to neuropathology. However, several open questions remain regarding (1) causality and mechanism(s), (2) specificity versus generalizability of associations, and (3) timing.

DISCUSSION

To inform potential intervention efforts, the field must address complex open questions about whether, how, when, and for whom well-being influences dementia risk. The majority of existing research on well-being and cognitive health is correlational, and few studies have tested potential mechanisms that may explain those associations. Further, relatively little is known about the generalizability of associations across different aspects of well-being and for different sociocultural groups. Finally, we do not yet understand when in the life span and on what timescale well-being might influence cognitive health. We discuss challenges and opportunities for addressing each of these open questions, including concrete recommendations for research designs and use of open science practices.

Purpose in life promotes resilience to age-related brain burden in middle-aged adults

BACKGROUND

Disease-modifying agents to counteract cognitive impairment in older age remain elusive. Hence, identifying modifiable factors promoting resilience, as the capacity of the brain to maintain cognition and function with aging and disease, is paramount. In Alzheimer's disease (AD), education and occupation are typical cognitive reserve proxies. However, the importance of psychological factors is being increasingly recognized, as their operating biological mechanisms are elucidated. Purpose in life (PiL), one of the pillars of psychological well-being, has previously been found to reduce the deleterious effects of AD-related pathological changes on cognition. However, whether PiL operates as a resilience factor in middle-aged individuals and what are the underlying neural mechanisms remain unknown.

METHODS

Data was obtained from 624 middle-aged adults (mean age 53.71 ± 6.9; 303 women) from the Barcelona Brain Health Initiative cohort. Individuals with lower (LP; N = 146) and higher (HP; N = 100) PiL rates, according to the division of this variable into quintiles, were compared in terms of cognitive status, a measure reflecting brain burden (white matter lesions; WMLs), and resting-state functional connectivity, examining system segregation (SyS) parameters using 14 common brain circuits.

RESULTS

Neuropsychological status and WMLs burden did not differ between the PiL groups. However, in the LP group, greater WMLs entailed a negative impact on executive functions. Subjects in the HP group showed lower SyS of the dorsal default-mode network (dDMN), indicating lesser segregation of this network from other brain circuits. Specifically, HP individuals had greater inter-network connectivity between specific dDMN nodes, including the frontal cortex, the hippocampal formation, the midcingulate region, and the rest of the brain. Greater functional connectivity in some of these nodes positively correlated with cognitive performance.

CONCLUSION

Expanding previous findings on AD pathology and advanced age, the present results suggest that higher rates of PiL may promote resilience against brain changes already observable in middle age. Furthermore, having a purposeful life implies larger functional integration of the dDMN, which may potentially reflect greater brain reserve associated to better cognitive function.