Mid-to-late-life social network size and resilience to neurodegeneration: the Framingham Heart Study

Background Social stimulation from having large networks may build cognitive reserve and contribute to cognitive resilience. However, limited research has assessed whether this relationship differs across the adult life course. We examined the relationship between social network size and resilience to neurodegeneration in memory, language, and executive function among mid-to-late-life adults. Methods The sample included 1,602 participants from the Framingham Heart Study Offspring cohort who completed the Berkman-Syme Social Network Index (SNI) questionnaire, had available plasma total tau (t-tau) measures at Exam 8, and had neuropsychological (NP) factor scores in memory, language, and executive function. Social network size was operationalized through a calculated SNI score and categorized into small, medium, and large networks. Cognitive resilience was operationalized using a residual approach by regressing each NP factor score on the plasma t-tau measure. Linear regression was used to assess associations between social network size and cognitive resilience, adjusting for age, sex, education, APOE ε4 allele carrier status, time between the most recent NP exam visit date and Exam 8 date, physical activity, smoking status, and depressive symptoms. Models were stratified by midlife (age 47–64 years) and late-life (age 65–91 years) groups. Results Average age was 67 years with most participants identifying as female (n = 880; 55%). By age group, more participants were in the late-life group (n = 918; 57%) compared to the midlife group (n = 684; 43%). Large social network size was significantly associated with greater resilience to neurodegeneration in memory compared to small social network size (β = 0.070; 95% CI = 0.007–0.133). There were no significant associations between large social networks and resilience to neurodegeneration in language or executive function. In the stratified models, large social networks were only associated with resilience to neurodegeneration in executive function among the midlife group (β = 0.110; 95% CI = 0.010–0.210). Conclusions Large social networks may promote greater resilience to neurodegeneration in memory among mid-to-late-life adults. Specific to middle-aged adults was a significantly greater resilience in executive function associated with large networks. Additional studies in more diverse samples are needed to replicate and generalize our findings to other groups.