- Titel
- Impact of Social Isolation on Grey Matter Structure and Cognitive Functions
- Zitierfähige Url:
- https://nbn-resolving.org/urn:nbn:de:bsz:15-qucosa2-976783
- Datum der Einreichung
- 02.05.2024
- Datum der Verteidigung
- 08.05.2025
- Abstract (EN)
- Dementia is a major public health concern and will become an even more pressing issue due to the forthcoming global demographic developments. The severe limitations of available treatment options render preventative measures pivotal to any endeavour aiming to reduce the burden of this disease. Social isolation has been linked to manifold adverse health outcomes including cognitive decline and dementia and thus is a key public health concern. Still, high-quality neuroimaging studies of this potential risk factor of dementia in large longitudinal datasets are lacking and existing studies did not distinguish between- and within participant effects and often did not offer reliable measures and clear conceptualisation of social isolation. Therefore, we investigated the associations of social isolation with grey matter structure and cognitive functions in this pre-registered longitudinal analysis of a large cognitively healthy sample of 1992 participants (50–82years old, 921women, 1409 participants at follow-up). To measure social isolation, we employed the Lubben Social Network Scale, a validated tool whose items are well suited to assess this aspect of participants’ social life. We employed rigorously quality controlled FreeSurfer segmentations leveraging the longitudinal structure of the data on advanced high-resolution T1-MRIs at 3 Tesla and thorough neuropsychological testing to accurately measure our outcomes of interest. For our statistical analyses, we combined linear mixed effects models and structural equation modelling and provided frequentist as well as Bayesian measures of significance. In accordance with our pre-specified hypotheses, we showed a significant association of smaller hippocampal volumes with stronger baseline social isolation and increases in social isolation over the course of around six years. Both predictors had an effect size per point on the Lubben Social Network Scale comparable to a 2.5 month difference in baseline age. Perspicuously put, assuming ceteris paribus, the difference between having 1 or 3–4 close and supportive friends is comparable to a 1-year difference in hippocampal ageing. Furthermore, we found significant associations of stronger baseline social isolation with lower executive functions, memory, and processing speed. For increases in social isolation, confidence intervals were wider but effect sizes, except for executive functions, were similar in magnitude to that of baseline social isolation. This observed within-participant effect is of particular relevance as it implies social isolation to indeed be a modifiable risk factor of cognitive decline and thus a promising target for public health strategies. In multiple sensitivity analyses, we showed the robustness of our findings. Neither applying less or stricter exclusion criteria, only including participants with two timepoints, nor controlling for the impact of the ongoing pandemic changed our results substantially. Likewise, analyses only including participants with two timepoints and using standard mean and within scores, using a hypertension cut-off of 140 mmHg, additionally controlling for physical activity or for sleep quality, and standardizing cognitive functions using the baseline mean rather than the grand mean confirmed the regression coefficients of our models in terms of direction and size. Moreover, we found clusters of decreased cortical thickness in the cuneus, precuneus, precentral, posterior cingulate, supramarginal, and middle frontal gyrus associated with social isolation cross-sectionally or longitudinally. Mediation analysis in smaller sample sizes testing potential effects of social isolation through lowering adverse effects of stress revealed no significant effects. Likewise, analogous analyses of the mediating role of hippocampal volume in the link between social isolation and cognitive functions did not yield significant results. We did not find statistical evidence indicating social isolation to be a causal risk factor. Yet, from a theoretical point of view, the reliable detection of an adverse effect in a cognitively healthy sample, is hardly compatible with the competing hypothesis of reverse causality underlying this association. In sum, this large-scale population neuroimaging analysis adds robust support to the view that social isolation is associated with accelerated brain ageing and cognitive decline in non-demented adults in mid- to late-life. Our findings imply that social contact protects from detrimental processes and thereby preserves brain structure and function. By identifying both adverse between- and within-participant effects of social isolation, we clarified that social isolation is not an immutable character trait but a potential target for preventive interventions. Henceforth, targeting social isolation through tailored strategies might contribute to maintaining brain health into old age. Whether a public health strategy directed at individuals or the population as a whole is more appropriate to pursue this end is subject to ongoing investigations. Throughout this project, we have adhered to open science practices like thorough preregistration, preprinting, open source coding and open access publishing to increase the transparency, accessibility and reproducibility of our study. Moreover, we incorporated the method of reflexivity, commonly practiced in qualitative research, to further strengthen the rigour and transparency of our work.
- Anderes Format
- Impact of social isolation on grey matter structure and cognitive functions: A population-based longitudinal neuroimaging study
Link: https://elifesciences.org/articles/83660#abstract - Freie Schlagwörter (EN)
- epidemiology, social isolation, grey matter structure, cognitive functions
- Klassifikation (DDC)
- 610
- Den akademischen Grad verleihende / prüfende Institution
- Universität Leipzig, Leipzig
- Version / Begutachtungsstatus
- aktualisierte Version
- URN Qucosa
- urn:nbn:de:bsz:15-qucosa2-976783
- Veröffentlichungsdatum Qucosa
- 25.06.2025
- Dokumenttyp
- Dissertation
- Sprache des Dokumentes
- Englisch
- Lizenz / Rechtehinweis
CC BY 4.0