Early childhood adversity and late-life depressive symptoms: unpacking mediation and interaction by adult socioeconomic status.

PURPOSE

Adverse childhood experiences (ACEs) have been linked to diminished health achievement across the life course. However, few studies have rigorously investigated the role of adult socioeconomic status (SES) as a mediator and an effect modifier of the association between ACEs and late-life depression. We used a four-way decomposition analysis to examine the relative contributions of mediation and interaction by low adult SES to the association between ACEs and late-life depression.

METHODS

Data came from two waves (2013 and 2016) of the Japan Gerontological Evaluation Study, a nationwide cohort of older people (n = 7271). ACEs were determined as ≥ 2 experiences of the following: parental loss, parental divorce, parental mental illness, domestic violence, physical abuse, psychological neglect, psychological abuse, and economic disadvantage. Low adult SES was defined as earning < 2 million yen of income and < 10 years of schooling. Depressive symptoms were assessed using the Geriatric Depression Scale.

RESULTS

Controlled direct effect (coefficient 0.28; 95% CI 0.08-0.46) accounted for 69.1% of the total effect, which was greater than the other three estimates for the decomposed effects (reference interaction 20.8%, mediated interaction 5.7%, and pure indirect effect 4.4%). Adult SES accounted for 10.1% (via mediation) and 26.5% (via exposure-mediator interaction) of the total association between ACEs and depressive symptoms, respectively.

CONCLUSION

ACEs appeared to be a strong and independent determinant of depressive symptoms in later life. Nonetheless, the interaction between ACEs and adult SES indicates that achieving high adult SES could mitigate the adverse effect of ACEs on late-life depression.