Social relationship factors, cognitive activity engagement and cognitive decline across 25 years in the Maastricht Ageing Study.

Background: Social relationship factors and cognitive activity engagement have been suggested as protective for cognitive decline and dementia. However, relatively few studies have addressed the risk for reverse causation with extended follow‐up periods. This study therefore aimed at examining associations between those factors and cognitive decline across up to 25 years. Method: We used data of 1,823 participants of the Maastricht Ageing study, who received baseline measurements of social relationship factors (social network size, social activity engagement and loneliness) and cognitive activity engagement (e.g. hours per week spent with reading books) from 1993 to 1995. Associations with baseline levels and change in memory, processing speed and executive functioning until the fifth Wave of follow‐up (2019 to 2022) were assessed using linear‐mixed models, controlling for age, sex, education, and a summary score of ten risk and protective factors for cognitive decline and dementia (the LIfestyle for BRAinhealth/LIBRA score). Result: Mean age at baseline was 51.1 years (SD = 16.4) and 49.9% of participants were female. Participants were followed up for 17.3 years on average (SD = 9.1). At baseline, more frequent social activity engagement was positively associated with processing speed (p<.001). Moreover, larger social network size (p =.023), and more frequent cognitive activity engagement (p =.037) were associated with better executive functioning. Longitudinal analyses showed that people with smaller social network size (p<.001) and higher levels of loneliness had a steeper decline in processing speed from baseline to the 25‐year follow‐up (p =.020). People with higher levels of loneliness additionally showed a steeper decline in memory (p =.006). Conclusion: Social relationship factors were associated with cognitive function and decline across 25 years in a sample representative of the general Dutch adult population. Our findings support their role as potential targets for the maintenance of optimal cognitive functioning. [ABSTRACT FROM AUTHOR]