Work

The heritability of social connections among older adults and their associations with mental and cognitive health: Older Australian Twins Study

Year: 2026

Type: article

Abstract: Background Social connections might be protective against depressive and anxious symptoms and dementia in later life. The extent to which social connections are heritable versus modifiable in older age remains unknown. Aims We aimed to investigate the heritability of social connections and their influence on mental and cognitive health over time among older adults in a longitudinal cohort. Method We analysed data from the Older Australian Twins Study (333 monozygotic, 266 dizygotic twins; 65+ years) at three time-points over 6 years. We examined the factor structure and heritability of baseline social connections and their associations with mental and cognitive health longitudinally. Results We found three weakly heritable social connections factors: (a) interacting with friends/neighbours/community ( h 2 = 0.09, 95% CI: 0.00, 0.44); (b) family interactions/childcare ( h 2 = 0.13, 95% CI: 0.00, 0.43); (c) involvement in religious groups/caregiving ( h 2 = 0.00, 95% CI: 0.00, 0.19). Strong genetic correlations were observed between depressive symptoms and factors a ( r = −0.96) and b ( r = −0.60). More frequent baseline interactions with friends/neighbours/community were associated with fewer depressive symptoms cross-sectionally ( B = −0.14, p = .004) and longitudinally ( B = −0.09, p = 0.006), but the associations between social connections and cognitive health were not significant. Conclusions Social connections were weakly heritable, suggesting large environmental determination. Connections with friends/neighbours/community were associated with better mental health cross-sectionally and over time.

Source: The British Journal of Psychiatry

DOI: 10.1192/bjp.2025.10505