Abstract
BACKGROUND: Cardiometabolic health in children has become a growing global concern due to its long-term association with chronic diseases such as cardiovascular disease and type 2 diabetes. Diet quality plays a critical role in determining cardiometabolic health. This study explored the association between diet quality and cardiometabolic health indicators in Chinese children aged 8-10 years and assessed the mediating role of cardiorespiratory fitness (CRF). METHODS: A total of 1,389 third-grade students from Ningbo, China were included. Diet quality was assessed using a validated questionnaire to calculate a Global Dietary Recommendations (GDR) score, with higher scores indicating healthier dietary patterns. Anthropometric data and fasting blood samples were collected to evaluate metabolic markers. A cardiometabolic risk (CMR) score was calculated based on age- and sex-adjusted Z-scores for waist circumference, systolic blood pressure, triglycerides, total cholesterol to high-density lipoprotein cholesterol ratio, and homeostasis model assessment for insulin resistance (HOMA-IR). CRF was measured using the 20-meter shuttle run test. Generalized linear mixed models were used to examine associations, and mediation analysis was conducted to assess the mediating effect of CRF. RESULTS: After adjusting for age, sex, and physical activity, higher GDR scores were significantly associated with lower fasting insulin (β = -0.013; p = 0.023), lower HOMA-IR (β = -0.014; p = 0.019), and reduced CMR score (β = -0.074; p = 0.030). Stratified and interaction analyses revealed stronger associations in girls than in boys. Mediation analysis showed that CRF accounted for 26.1% of the association between GDR score and fasting insulin, 25.3% for HOMA-IR, and 32.9% for CMR score (all p < 0.05). CONCLUSION: In Chinese children, better diet quality is associated with more favorable cardiometabolic profiles. CRF showed a statistically significant mediating role in the cross-sectional association, highlighting the potential importance of both healthy eating and physical fitness in promoting cardiometabolic health in youth.