Educational inequalities in self-rated health and their mediators in late adulthood: Comparison of China and Japan

Education has an impact on health, but the magnitude of the impact may vary across countries. This cross-sectional study compared educational inequalities in health and their mediators in late adulthood between China and Japan, which both face rapid population aging. We studied the same age cohort (63–72 years) based on two nationwide population-based surveys in 2018: the China Health and Retirement Longitudinal Study (N = 5,277) and Japan’s Longitudinal Survey of Middle-Age and Elderly Persons (N = 20,001). The relative index of inequality (RII) in education was used to measure educational inequality in self-rated health (SRH). We then examined the extent to which income, smoking, leisure-time physical activity, and social participation mediated educational inequalities in SRH. In both countries, a lower educational level was associated with a higher risk of poor SRH; in China, however, the gradient was flatter. In China, the RII of education was 1.69 (95% confidence interval [CI]: 1.20–2.39) for men and 1.47 (95% CI: 1.06–2.05) for women. In Japan, meanwhile, RII was 2.70 (95% CI: 2.21–3.28) for men and 2.60 (95% CI: 2.13–3.18) for women. Our mediation analysis based on logistic regression models with bootstrapping also found that social participation was a key mediator of educational inequalities in health in both countries. In all, the results underscore that one’s relative position in educational inequalities is a reliable predictor of subjective health in late adulthood in both China and Japan.