The double burden of malnutrition: a cross-sectional study of associations between micronutrient deficiencies and cardiometabolic risk factors in chinese children and adolescents

The double burden of malnutrition (DBM)—the coexistence of micronutrient deficiencies and overweight/obesity—poses a growing challenge in pediatric populations. This cross-sectional study examined divergent associations of vitamin D, vitamin A, zinc, and iron deficiencies with cardiometabolic risk factors in Chinese children and adolescents (Causality cannot be inferred from these observational data). This cross-sectional study analyzed data from 9,585 children and adolescents aged 6–17 years from the Nutrition and Health Survey in Zhejiang Province (2022–2024). Micronutrient status was assessed using established cut-offs. Cardiometabolic outcomes included seven binary risk factors and the continuous metabolic syndrome score (cMetS). Modified Poisson regression with robust standard errors and multiple linear regression were used, adjusted for age, sex, residence, and energy intake. Vitamin D deficiency was associated with higher risk of hypertriglyceridemia (RR = 1.13, p = 0.005) and low HDL-C (RR = 1.45, p < 0.001), yet lower risk of hypercholesterolemia (RR = 0.85, p = 0.007) and hypertension (RR = 0.88, p = 0.022). Vitamin A deficiency was inversely associated with overweight/obesity (RR = 0.68, p < 0.001), hypertriglyceridemia (RR = 0.35, p < 0.001), and hypertension (RR = 0.68, p = 0.032). Zinc deficiency risk showed divergent associations: lower risk of overweight/obesity (RR = 0.85, p = 0.033) and hypertension (RR = 0.66, p < 0.001), yet higher risk of impaired fasting glucose (RR = 2.27, p < 0.001) and low HDL-C (RR = 1.62, p < 0.001). Iron deficiency was inversely associated with overweight/obesity (RR = 0.74, p = 0.002), hypertriglyceridemia (RR = 0.75, p = 0.005), and low HDL-C (RR = 0.38, p < 0.001). In the blood pressure subsample ( n = 3,492), cMetS was higher with vitamin D deficiency and zinc deficiency risk (β = 0.356 and 0.515) but lower with vitamin A and iron deficiencies (β = − 0.700 and − 0.374; all p ≤ 0.013). The inverse associations for vitamin A and iron were attenuated after additional adjustment for BMI z-score, whereas the adverse associations for vitamin D and zinc remained robust. Micronutrient deficiencies showed nutrient-specific, bidirectional associations with cardiometabolic risk in this cross-sectional study. Vitamin D and zinc deficiencies were consistently associated with adverse profiles, whereas the inverse associations for vitamin A and iron should not be interpreted as evidence of protective effects of deficiency; they likely reflect adiposity-driven metabolic and inflammatory alterations. Precision nutrition approaches that account for metabolic context warrant evaluation for micronutrient screening and supplementation in youth with obesity.