Multidimensional Assessment of Subjective Well-Being and Risk of Dementia: Findings from the UK Biobank Study

Social participation, subjective well-being, and cognitive function as serial mediators between tooth loss and functional limitations in older Chinese adults

BACKGROUND

Although tooth loss appears to be related to functional limitations, the mechanisms that underpin this relationship are unknown. We sought to address this knowledge gap by examining a multiple mediation hypothesis whereby tooth loss is predicted to indirectly affect functional limitations through social participation, subjective well-being, and cognitive function.

METHODS

This study included 7,629 Chinese adults from the 2017/2018 Chinese Longitudinal Healthy Longevity Survey wave. The serial mediation effects were examined using Model 6 in the Hayes' PROCESS macro for SPSS.

RESULTS

Tooth loss was significantly related to functional limitations. There was a direct (β = - 0.0308; 95% CI, - 0.0131 to - 0.0036) and indirect (β = - 0.0068; 95% CI, - 0.0096 to - 0.0041) association between tooth loss and instrumental activities of daily living (IADL) limitations, but only an indirect correlation with activities of daily living (ADL) limitations (β = - 0.0188; 95% CI, - 0.0259 to - 0.0121). Social participation, subjective well-being, and cognitive function serially mediated the relationship between tooth loss and ADL/IADL limitations.

CONCLUSION

The association between tooth loss and functional limitations is serially mediated by social participation, subjective well-being, and cognitive function. Our findings underscore the necessity of considering psychological and social factors as integrated healthcare approaches for the functional health of older adults.

Purpose in Life and Cognitive Function: Evidence for Momentary Associations in Daily Life

Background and Objectives

Purpose in life is associated with healthier cognitive outcomes in older adulthood. This research examines within-person dynamics between momentary purpose and cognitive function to provide proof of concept that increases in purpose are associated with better cognitive performance.

Research Design and Methods

Participants (N = 303; 54% female; Mage = 51.71, SD = 7.32) completed smartphone-based momentary assessments of purpose and short cognitive tasks 3 times a day for 8 days.

Results

In moments when participants felt more purpose driven than their average, they had faster processing speed (b = -1.240, SE = 0.194; p < .001), independent of person, temporal, and contextual factors and practice effects. Momentary purpose was unrelated to visual working memory performance (b = -0.001, SE = 0.001; p = .475). In contrast to purpose, momentary hedonic affect (e.g., happiness) was unrelated to momentary cognition.

Discussion and Implications

Feeling more momentary purpose may support faster processing speed in daily life. Such evidence provides stage 0 support for a purpose-based intervention for healthier cognition, which may be particularly useful in middle adulthood and the transition to older adulthood before the onset of cognitive impairment.

The Association between Happiness and Cognitive Function in the UK Biobank

Feelings of happiness have been associated with better performance in creative and flexible thinking and processing. Less is known about whether happier individuals have better performance on basic cognitive functions and slower rate of cognitive decline. In a large sample from the UK Biobank (N=17,885; Age 40-70 years), we examine the association between baseline happiness and cognitive function (speed of processing, visuospatial memory, reasoning) over four assessment waves spanning up to 10 years of follow-up. Greater happiness was associated with better speed and visuospatial memory performance across assessments independent of vascular or depression risk factors. Happiness was associated with worse reasoning. No association was found between happiness and the rate of change over time on any of the cognitive tasks. The cognitive benefits of happiness may extend to cognitive functions such as speed and memory but not more complex processes such as reasoning, and happiness may not be predictive of the rate of cognitive decline over time. More evidence on the association between psychological well-being and different cognitive functions is needed to shed light on potential interventional efforts.

The association between personality and plasma biomarkers of astrogliosis and neuronal injury

Personality traits have been associated with the risk of dementia and Alzheimer's disease neuropathology, including amyloid and tau. This study examines whether personality traits are concurrently related to plasma glial fibrillary acidic protein (GFAP), a marker of astrogliosis, and neurofilament light (NfL), a marker of neuronal injury. Cognitively unimpaired participants from the Baltimore Longitudinal Study on Aging (N = 786; age: 22-95) were assayed for plasma GFAP and NfL and completed the Revised NEO Personality Inventory, which measures 5 domains and 30 facets of personality. Neuroticism (particularly vulnerability to stress, anxiety, and depression) was associated with higher GFAP and NfL. Conscientiousness was associated with lower GFAP. Extraversion (particularly positive emotions, assertiveness, and activity) was related to lower GFAP and NfL. These associations were independent of demographic, behavioral, and health covariates and not moderated by age, sex, or apolipoprotein E genotype. The personality correlates of astrogliosis and neuronal injury tend to be similar, are found in individuals without cognitive impairment, and point to potential neurobiological underpinnings of the association between personality traits and neurodegenerative diseases.