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

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.