Institutional change and health equity: Tracing the impact of market transition on health inequalities in China, 1993–2015

Health inequalities are intrinsically linked to social stratification, yet how institutional change, like market transition, reshapes these inequalities requires further elucidation. This study conceptualizes market transition as encompassing two dimensions: internal market-oriented reforms and external integration into the global market. Drawing on the market transition debate, we investigate the evolving mechanisms shaping health inequality in China. Utilizing China Health and Nutrition Survey (CHNS) data (1993–2015), we employ supervised machine learning models for exploratory analysis and multilevel linear probability models for confirmatory analysis. Our findings reveal an intensification of health inequalities based on working unit (danwei) and household registration (hukou) systems—key redistributive mechanism elements—alongside increasing disparities rooted in income and education levels, central to market mechanisms. Crucially, China's WTO accession marked a turning point, revealing non-linear temporal dynamics for redistributive mechanisms. Post-WTO, regional marketization exacerbated hukou-based urban-rural health gaps. Conversely, WTO accession moderated the widening effect of the marketization index on sectoral health gaps. The health gap of cadres relative to non-cadres remained stable. This study demonstrates the co-existence and complex, period-specific evolution of market and reconfigured redistributive mechanisms of health inequalities. It underscores the need for transitional societies to address both market-driven disparities and unequal public service distribution to advance health equity.