Adverse Childhood Experiences and Dementia: Interactions With Social Capital in the Japan Gerontological Evaluation Study Cohort

Abstract

Introduction: This study investigated whether individual-level social capital modifies the association between adverse childhood experiences and dementia onset.

Methods: A 3-year follow-up (2013-2016) was conducted among participants who were physically and cognitively independent in the Japan Gerontological Evaluation Study. Dementia incidence for 16,821 participants was assessed through the public long-term care insurance system. Adverse childhood experiences before age 18 years and social capital were assessed using a self-report questionnaire at baseline in 2013. A total of 7 adverse childhood experiences were assessed: parental death, parental divorce, parental mental illness, family violence, physical abuse, psychological neglect, and psychological abuse. To assess social capital's mediating effect, 3 individual social capital items were measured (community trust, reciprocity, and attachment). The overall social capital score was categorized as low (<10th percentile), middle (10th-90th percentile), or high (>90th percentile). Data were analyzed in 2020.

Results: During the 3-year follow-up, 652 dementia cases occurred. Those with more adverse childhood experiences had a greater risk of dementia. Stratification by social capital score showed that the hazard ratio of ≥3 adverse childhood experiences (versus none) was 3.25 (95% CI=1.73, 6.10) among those with low social capital and 1.19 (95% CI=0.58, 2.43) among those with middle social capital. Among those with ≥3 adverse childhood experiences and high social capital, no dementia cases were observed.

Conclusions: Among older adults in Japan, adverse childhood experiences were associated with increased dementia incidence only for those with low social capital.