Trends, ethnic inequalities, and determinants of multiple nutrition-related health outcomes among Chinese children and adolescents aged 7–18 years: evidence from four national school health surveys, 2005–19

BACKGROUND: Eliminating all forms of malnutrition is essential for optimal child and adolescent development. In multi-ethnic China, nutrition-related conditions coexist, but ethnic-group patterns remain unclear. We assessed trends, between-ethnic inequalities, and co-occurrence among the Han majority and 26 ethnic minority groups. METHODS: We analysed four cross-sectional national school health surveys from 2005 to 2019, including 1 201 557 students aged 7-18 years. We estimated age-standardised and sex-standardised prevalence, ethnicity-level sociodemographic index (SDI) inequalities, and co-occurrence; anaemia analyses included 389 124 participants aged 7, 9, 12, and 14 years. Contextual associations and model-based population-attributable fractions (PAFs) were examined. FINDINGS: Between 2005 and 2019, overweight and obesity increased from 9·77% (95% CI 9·67-9·88) to 20·06% (19·92-20·20), obesity from 3·27% (3·21-3·34) to 8·18% (8·08-8·28), and high blood pressure from 8·81% (8·71-8·90) to 13·39% (13·28-13·51); stunting declined from 5·16% (5·08-5·24) to 2·12% (2·07-2·17) and thinness from 4·86% (4·78-4·94) to 2·55% (2·50-2·61), whereas anaemia remained prevalent (9·42% [9·24-9·60] in 2005 vs 10·40% [10·20-10·59] in 2019). Stunting remained concentrated among lower-SDI ethnic groups, whereas obesity and overweight and obesity were concentrated among higher-SDI groups and absolute inequalities widened. Among children with anaemia, overweight and obesity increased from 7·89% (7·32-8·46) to 18·19% (17·37-19·01); among those with stunting, overweight and obesity increased from 2·44% (2·18-2·70) to 6·89% (6·15-7·62). Higher education, health, and urbanisation indicators were associated with lower stunting odds; model-based joint PAFs were 16·39% for obesity and 22·01% for high blood pressure. INTERPRETATION: Across multi-ethnic China, the nutrition transition remains incomplete, with anaemia remaining common, stunting declining but persisting in some ethnic groups, and overweight and obesity and high blood pressure rising. Ethnic heterogeneity and increasing within-person co-occurrence of nutrition-related outcomes reveal an increasingly complex burden and limits of single-condition approaches, calling for integrated surveillance and tailored responses. FUNDING: National Key R&D Program of China, National Natural Science Foundation of China, Beijing Natural Science Foundation, Peking University Talent Introduction Program Project, and Peking University Health Science Center Innovation Fund for Outstanding Doctoral Students.