Social health and subsequent cognitive functioning in people aged 50 years and older: examining the mediating roles of depressive symptoms and inflammatory biomarkers in two European longitudinal studies.

BACKGROUND: Social health markers, including marital status, contact frequency, network size, and social support, have been shown to be associated with cognition. However, the mechanisms underlying these associations remain poorly understood. We investigated whether depressive symptoms and inflammation mediated associations between social health and subsequent cognition. METHODS: In the English Longitudinal Study of Ageing (ELSA), a nationally representative longitudinal study in England, UK, we sampled 7136 individuals aged 50 years or older living in private households without dementia at baseline or at the intermediate mediator assessment timepoint, who had recorded information on at least one social health marker and potential mediator. We used four-way decomposition to examine to what extent depressive symptoms, C-reactive protein, and fibrinogen mediated associations between social health and subsequent standardised cognition (verbal fluency and delayed and immediate recall), including cognitive change, with slopes derived from multilevel models (12-year slope). We examined whether findings were replicated in the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K), a population-based longitudinal study in Sweden, in a sample of 2604 individuals aged 60 years or older living at home or in institutions in Kungsholmen (central Stockholm) without dementia at baseline or at the intermediate mediator assessment timepoint (6-year slope). Social health exposures were assessed at baseline, potential mediators were assessed at an intermediate timepoint (wave 2 in ELSA and 6-year follow-up in SNAC-K); cognitive outcomes were assessed at a single timepoint (wave 3 in ELSA and 12-year follow-up in SNAC-K), and cognitive change (between waves 3 and 9 in ELSA and between 6-year and 12-year follow-ups in SNAC-K). FINDINGS: The study sample included 7136 participants from ELSA, of whom 3962 (55·5%) were women and 6934 (97·2%) were White; the mean baseline age was 63·8 years (SD 9·4). Replication analyses included 2604 participants from SNAC-K, of whom 1604 (61·6%) were women (SNAC-K did not collect ethnicity data); the mean baseline age was 72·3 years (SD 10·1). In ELSA, we found indirect effects via depressive symptoms of network size, positive support, and less negative support on subsequent verbal fluency, and of positive support on subsequent immediate recall (pure indirect effect [PIE] 0·002 [95% CI 0·001-0·003]). Depressive symptoms also partially mediated associations between less negative support and slower decline in immediate recall (PIE 0·001 [0·000-0·002]) and in delayed recall (PIE 0·001 [0·000-0·002]), and between positive support and slower decline in immediate recall (PIE 0·001 [0·000-0·001]). We did not observe mediation by inflammatory biomarkers. Findings of mediation by depressive symptoms in the association between positive support and verbal fluency and between positive support and change in immediate recall were replicated in SNAC-K. INTERPRETATION: The findings of this study provide new insights into mechanisms linking social health with cognition, suggesting that associations between interactional aspects of social health, especially social support, and cognition are partly underpinned by depressive symptoms. FUNDING: EU Joint Programme-Neurodegenerative Disease Research (JPND) and Alzheimer's Society. TRANSLATION: For the Swedish translation of the abstract see Supplementary Materials section.

Do Health and Well-Being Change Around the Transition to Informal Caring in Early Adulthood? A Longitudinal Comparison Between the United Kingdom and Germany.

PURPOSE: Providing care in early adulthood may have long-term consequences, given the importance of this life stage for life-course transitions. This study aimed to analyze how the transition into caring during young adulthood (17-29 years old) influenced health and life satisfaction in the United Kingdom and Germany. METHODS: Datasets were from 10 annual waves of the UK Household Longitudinal Study and the German Socioeconomic Panel between the years 2009-2018. We used propensity score matching to match young adult carers (YACs) to similar noncarers to address the endogeneity of unpaid care provision. Then we applied piecewise growth curves to observe changes in self-rated health (United Kingdom N = 2,851; Germany N = 454) and life satisfaction (United Kingdom N = 2,263; Germany N = 449) between YAC and noncarers before, during, and after the onset of care. We assessed carer status, weekly hours spent on care, and duration of care. RESULTS: In the United Kingdom, life satisfaction decreased and the probability of reporting poor health increased after becoming a YAC, particularly for those who reported caring for more weekly hours. However, no such differences were found between YAC and noncarers in Germany. DISCUSSION: The onset and intensity of caring responsibilities during early adulthood influenced health and life satisfaction in the United Kingdom but not in Germany. One possible interpretation for these differences may be attributed to the different welfare contexts in which YACs are providing informal care. Our results highlight the importance of identifying and supporting the needs of young adults who are providing informal care while making key life-course transitions.

Examining the Interrelationships Between Social Isolation and Loneliness and Their Correlates Among Older British Adults Before and During the COVID-19 Lockdown: Evidence From Four British Longitudinal Studies.

Background and Objectives: Unprecedented social restrictions during the coronavirus disease 2019 (COVID-19) pandemic have provided a new lens for considering the interrelationship between social isolation and loneliness in later life. We present these interrelationships before and during the COVID-19 restrictions and investigate to what extent demographic, socioeconomic, and health factors associated with such experiences differed during the pandemic. Research Design and Methods: We used data from four British longitudinal population-based studies (1946 NSHD, 1958 NCDS, 1970 BCS, and ELSA, N = 12,129). Rates, co-occurrences, and correlates of social isolation and loneliness are presented prior to and during the early stage of the COVID-19 pandemic and the interrelationships between these experiences are elucidated in both periods. Results: Across the Four studies, prepandemic proportions reporting social isolation ranged from 15% to 54%, with higher rates in older ages (e.g., 32% of individuals aged 70-79 years and 54% of those more than 80). During the pandemic, the percentage of older people reporting both social isolation and loneliness and isolation only slightly increased. The interrelationship between social isolation and loneliness did not change. Associations between sociodemographic and health characteristics and social isolation and loneliness also remained consistent, with greater burden among those with higher economic precarity (females, nonhomeowners, unemployed, illness, and greater financial stress). Discussion and Implications: There were already large inequalities in experiences of social isolation and loneliness and the pandemic had a small impact on worsening extent and inequalities in these. The concepts of loneliness and social isolation are not interchangeable, and clarity is needed in how they are conceptualized, operationalized, and interpreted. Given many older adults experience high levels of social isolation, there should be greater emphasis on reducing social isolation and the inequalities observed in who experiences greater isolation and loneliness.