Background: Increasing evidence suggests an impact of childhood disadvantage on late-life functional impairment in Western countries. However, the processes by which childhood disadvantage affects functional capacity are influenced by several factors unique to particular societies. We examined the impact of childhood disadvantage on functional decline among older Japanese, using a large-scale prospective cohort study.
Methods: Data came from surveys conducted in 2010 and 2013 as part of the Japan Gerontological Evaluation Study (JAGES), a nationwide cohort study targeting community-dwelling people aged 65 years and over. Childhood disadvantage included subjective childhood socioeconomic status (SES), body height, and educational level. The sample was stratified by age at baseline (65-69, 70-74, 75-79, and ≥ 80 years).
Results: A total of 11,601 respondents were analyzed. In the 65-69-year group, lower childhood SES was associated with functional decline but this association was mediated by adult SES. In contrast, childhood SES was independently associated with functional decline in the older cohort. In the 75-79-year group, lower childhood SES was associated with functional decline. However, in the ≥ 80-year group, people with higher childhood SES were more likely to experience functional decline. Shorter height was associated with functional decline in the 70-74-year group. Higher education was related to functional decline in all age groups except the ≥ 80-year group.
Conclusions: These findings suggest that childhood disadvantage affects functional decline but its effect varies by age cohort. The mechanisms underlying the association between childhood disadvantage and functional decline may be influenced by social and historical context.