Widening disparities in health between educational levels and their determinants in later life: evidence from a nine-year cohort study

Background: Education has attracted more attention as a key determinant of health in later life. In this study, the hypothesis that widened educational disparities in health can be observed in later life was investigated, and the factors that mediated the association between education and changes in health were also assessed. Methods: Using the 9-year (10-wave) longitudinal data of 20,024 individuals (9320 men and 10,704 women) aged 5059 years at baseline, collected from a nationwide population survey in Japan (2005-2014), the changes in self-rated health, functional limitations, and psychological distress between educational levels were compared. Mediation analysis was further conducted to assess the factors that mediated the association between education and changes in health, with reference to six types of potential mediators (household spending, social participation, leisure-time physical activity, smoking, problem drinking, and regular health check-ups). The analyses were conducted separately for men and women. Results: All three health variables rapidly deteriorated among lower-educated men and women. For men, the six potential mediators mediated 55.2%, 64.3%, and 47.3% of the associations between educational levels and changes in self-rated health, functional limitations, and psychological distress, respectively. The proportions for women were 42.0%, 49.5%, and 58.8%, respectively. Social participation was the primary mediator, followed by physical activity, regular health check-ups, and smoking. In general, no substantial or consistent differences were observed between men and women. Conclusions: The results suggested that policy measures that encourage social participation and promote healthy behaviors can improve educational disparities in health in later life.