Individual-, institutional-, and societal-level factors and their interactions in the association between minority ethnicity and self-reported health outcomes in China, 2010-2021: a repeated cross-sectional study.

BACKGROUND: Ecosocial theory emphasizes examining individual-, institutional-, and societal-level factors-and their interactions-when investigating racial and ethnic health disparities. This study evaluated the relationship between minority group ethnicity and self-reported health outcomes by comparing ethnic minorities (as a combined group) with the Han majority population in China. METHODS: Cross-sectional data from seven waves (2010-2021) of the nationally representative Chinese General Social Survey were analyzed. Among 66,057 respondents (61,036 Han and 5,021 ethnic minorities), we first described temporal trends in self-reported overall health, social functioning, and depressive symptoms by ethnicity. We then used mixed-effects ordinal regression models to assess associations between minority (comparison group) versus Han (reference) ethnicity and these three health outcomes. Models were adjusted for individual-level factors (e.g., sociodemographic), institutional factors (e.g., healthcare resources), societal factor (living region), and interactions (minority ethnicity status, living region, and institutional factors). McFadden's pseudo-R-squared was calculated to determine the relative contributions of individual-, institutional-, and societal-level factors, as well as their interactions. RESULTS: Among 66,057 respondents (92.4% Han, 7.6% ethnic minorities), minority ethnicity compared to Han ethnicity was associated with better overall health (Odds Ratio [OR] 2.15, 95% CI 1.52-3.05), social function (OR: 1.68, 95% CI 1.18-2.39), and lower frequency of depressive symptoms (OR: 0.64, 95% CI 0.47-0.86) after adjustments for potential confounding variables. Individual-level factors explained most of the variance: 94.2% (overall health), 90.0% (social function), and 75.0% (frequency of depressive symptoms). Institutional- and societal-level factors contributed 3.0%, 6.1%, and 7.0%, while interactions accounted for 2.8%, 3.8%, and 18%, respectively. CONCLUSIONS: As a group, ethnic minorities in China were associated with better health outcomes versus the Han majority. While individual-level factors accounted for most of the variation in health outcomes, institutional- and societal-level factors, as well as their interactions, also contributed. Findings demonstrate context-specific applications of social epidemiological theories in China.