Childhood Socioeconomic Status and Onset of Depression among Japanese Older Adults: The JAGES Prospective Cohort Study

Objective: Previous investigations on the impact of childhood socioeconomic status (SES) on depression have focused on middle-aged adults in Western countries. It is unknown whether childhood SES has a long-latency effect on the onset of depression among older adults. Design: Prospective cohort study. Setting: Data were from the Japan Gerontological Evaluation Study. Participants: We analyzed 10,458 individuals aged 65 years and older without depression (Geriatric Depression Scale <5) at baseline in 2010. Measurements: Participants rated their childhood SES at the age of 15 years according to standards at that time. We used binomial regression analyses with log link and with adjustment for known and potential risk factors to evaluate the risk of depression onset by 2013. Results: Overall, 13.9% of participants newly reported depression in 2013. After adjusting for age and sex, low childhood SES was positively associated with depression onset (adjusted risk ratio [ARR]: 1.44, 95% confidence interval [CI]: 1.23-1.69). The association decreased after adjustment for education (ARR: 1.33; 95% CI: 1.13-1.57). Even after adjustments for adult SES, current disease status, health behaviors, and social relationships, the association remained significant (ARR: 1.27; 95% CI: 1.08-1.50). The link was stronger among the younger old (6574 years) than the oldest old (>= 75 years). Conclusions: Low childhood SES, perhaps due to poverty in post-World War II, has a long-latency effect on the onset of depression among older Japanese adults. The impact of childhood SES on depression was weaker among the oldest old, suggesting survival effects for healthy older Japanese people.