Year: 2026
Type: dissertation
Study design: Observational Study
Abstract: The dissertation examined the bidirectional associations between cognition and social relationships in very old age. Very old age, defined as 80 years and older, represents a life phase with unique strengths and vulnerabilities. In this age group, cognitive impairment is a common health risk. Lifestyle factors have been shown to play an important role in preventing cognitive impairment. In particular, social relationships have been identified as a key modifiable lifestyle factor. Prior studies have shown that multiple social aspects are associated with higher cognitive functioning and a lower risk of cognitive impairment in old age. Meanwhile, most findings stem from research on adults younger than 80 years, while there is reason to assume that the associations are age-dependent. Furthermore, research has often overlooked the bidirectional nature of the associations between social relationships and cognition, as cognitive impairment also affects social relationships. Based on this theoretical framework, the dissertation addressed two main research questions within three scientific articles. The first question investigated whether and which social aspects are associated with cognition in very old age and may thus help reduce the risk of cognitive impairment in this age group. The second research question examined how cognitive impairment is linked to social relationships and how these associations are connected to well-being. Both research questions were answered using data from the Study on Quality of Life and Well-Being of the Very Old in North Rhine-Westphalia (NRW80+ Study). In the first study (n = 518), structural social aspects, as measures of social bridging, were positively associated with global cognition throughout very old age. Functional/qualitative aspects, as measures of social bonding, showed no significant associations. The second study also observed positive cross-sectional associations between structural social aspects, global cognition, and episodic memory (n = 1207), but no associations between social aspects and cognition 2 years later (n = 639). The third study (n = 1516) found that individuals with cognitive impairment, particularly with severe forms, showed a high risk of poor social and mental health. Moreover, lower social outcomes were more strongly associated with reduced well-being among participants with severe cognitive impairment compared to those without cognitive impairment. In summary, the dissertation revealed that social aspects, as related to social bridging, are positively associated with cognitive functioning in very old age. The fact that the associations were only cross-sectional suggests that social relationships serve as a life course resource rather than a short-term intervention target for cognition in very old age. Moreover, the findings highlight the importance of social relationships not only in preventing cognitive impairment but also in supporting the well-being of those affected. Individuals with cognitive impairment, who represent a large proportion of the very old population, should be included more in future research projects. Finally, the dissertation recommends promoting social participation throughout the lifespan. Particularly in very old age, peripheral social networks tend to shrink for several reasons, while close relationships are often strengthened. Encouraging social participation supports the maintenance of these broader ties, benefiting both cognitive functioning and well-being in very old age. Targeted measures should include reducing age-related barriers to social participation, such as those due to sensory, physical, and cognitive impairment.
Author: Vogel, Selina
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7222854158