Social relationship factors, depressive symptoms, and incident dementia: a prospective cohort study into their interrelatedness

Lukas A Duffner; Kay Deckers; Dorina Cadar; Marjolein E de Vugt; Sebastian Köhler

doi:10.1017/S0033291724001272

Social relationship factors, depressive symptoms, and incident dementia: a prospective cohort study into their interrelatedness

Psychol Med. 2024 Sep 4:1-11. doi: 10.1017/S0033291724001272. Online ahead of print.

Authors

Lukas A Duffner¹, Kay Deckers¹, Dorina Cadar^{2

3}, Marjolein E de Vugt¹, Sebastian Köhler¹

Affiliations

¹ Alzheimer Centrum Limburg, Mental Health and Neuroscience Research Institute (MHeNS), Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, Maastricht University, The Netherlands.
² Department of Behavioural Science and Health, Institute of Epidemiology and Health, University College London, UK.
³ Department of Neuroscience, Centre for Dementia Studies, Brighton and Sussex Medical School, Brighton, UK.

PMID: 39228209
DOI: 10.1017/S0033291724001272

Abstract

Background: Different aspects of social relationships (e.g., social network size or loneliness) have been associated with dementia risk, while their overlap and potentially underlying pathways remain largely unexplored. This study therefore aimed to (1) discriminate between different facets of social relationships by means of factor analysis, (2) examine their associations with dementia risk, and (3) assess mediation by depressive symptoms.

Methods: Thirty-six items from questionnaires on social relationships administered in Wave 2 (2004/2005) of the English Longitudinal Study of Ageing (n = 7536) were used for exploratory and confirmatory factor analysis. Factors were then used as predictors in Cox proportional hazard models with dementia until Wave 9 as outcome, adjusted for demographics and cardiovascular risk factors. Structural equation modeling tested mediation by depressive symptoms through effect decomposition.

Results: Factor analyses identified six social factors. Across a median follow-up time of 11.8 years (IQR = 5.9-13.9 years), 501 people developed dementia. Higher factor scores for frequency and quality of contact with children (HR = 0.88; p = 0.021) and more frequent social activity engagement (HR = 0.84; p < 0.001) were associated with lower dementia risk. Likewise, higher factor scores for loneliness (HR = 1.13; p = 0.011) and negative experiences of social support (HR = 1.10; p = 0.047) were associated with higher dementia risk. Mediation analyses showed a significant partial effect mediation by depressive symptoms for all four factors. Additional analyses provided little evidence for reverse causation.

Conclusions: Frequency and quality of social contacts, social activity engagement, and feelings of loneliness are associated with dementia risk and might be suitable targets for dementia prevention programs, partly by lowering depressive symptoms.

Keywords: cohort study; dementia; depressive symptoms; factor analysis; prevention; public health; risk reduction; social relationships; structural equation modeling.