Childhood Peer Relationships and Dementia Risk in Chinese Older Adults: A Mediation Analysis

Early-life social experiences significantly influence later-life health, yet the association between childhood peer relationships and dementia, as well as the underlying mechanisms, remains underexplored. This study aimed to investigate this association and the mediating roles of social disengagement and loneliness.

Leveraging data from 7574 adults aged ≥ 60 in the China Health and Retirement Longitudinal Study (2011-2018), we employed marginal structural models to assess the associations between childhood peer relationships and dementia risk in later life. Inverse odds ratio weighting was used to examine the mediating roles of formal and informal social disengagement and loneliness.

Individuals with deficits in childhood peer relationships had a higher risk of dementia (odds ratio [OR], 1.21; 95% confidence interval [CI], 1.10-1.34) compared with those with more positive experiences. This association was partially mediated by formal social disengagement (proportion mediated, 21.44%; 95% CI, 12.20%-40.94%), loneliness (proportion mediated, 22.00%; 95% CI, 13.42%-33.82%), and their combination with informal social disengagement (proportion mediated, 41.50%; 95% CI, 30.76%-66.07%). Informal social disengagement alone did not show a significant mediating effect.

In this cohort study of older Chinese adults, negative childhood peer relationship experiences were associated with an elevated risk of dementia in later life. Formal social disengagement and loneliness partially mediated this association. These findings underscore the importance of fostering positive social relationships in early life and suggest potential psychosocial strategies to mitigate dementia risk in older adults due to childhood peer relationship deficits.