From circumstances to efforts: the shifting determinants of health opportunity inequality in China

This study applies Roemer’s theory of equality of opportunity to construct an age-group comparative framework grounded in the circumstances–effort dichotomy. Using microdata from the China Family Panel Studies, the analysis employs ordered probit models and counterfactual decomposition techniques to assess health opportunity inequality and its structural components across age groups. The results indicate that approximately 34.92% of national health inequality is attributable to circumstances, highlighting the extent of health inequity. Provincial analysis identifies four archetypal patterns, including the “high equity–low circumstance dependence” and “high circumstance dependence–high inequality” models. Age-group analysis reveals a U-shaped pattern: the contribution of circumstances is 36.02% among young adults, declines to 28.12% among middle-aged adults, and rises to 38.17% among older adults. Childhood health remains consistently associated with adult health across all age groups, with the largest marginal effect observed among middle-aged adults. These findings provide empirical evidence and theoretical support for health equity policies that address both life-stage heterogeneity and regional disparities.