Stunting, Thinness, Obesity, and Double Burden of Malnutrition in Vietnamese Urban Children

Objectives: To characterize prevalence and secular trends in stunting, thinness, overweight, obesity, and the double burden of malnutrition (DBM) in urban Vietnamese children. Methods: We analyzed 249,745 annual health check visits from 97,111 children aged 18 months to 18 years attending a private school system in Hanoi, Ho Chi Minh City, and Haiphong from 2018 to 2025. Temporal trends in stunting, thinness, and obesity were modelled using generalized estimating equation (GEE) logistic regression. Results: A total of 51,034 males and 46,077 females were included. Stunting prevalence was low but rose significantly in both sexes (males: 0.7% to 1.3%, p=0.006, females: 0.7% to 1.7%, p<0.001), concentrated in children under 10 years (GEE OR/year=1.076 and 1.089, both p<0.05), females exceeded males by 2025. Obesity declined overall in males (21.4% to 17.0%) and females (6.2% to 5.0%, both p<0.001), but rose significantly among males aged 15-18 years (OR=1.055, p=0.021). Overweight increased in males (19.7% to 20.5%, p=0.010) but declined in females (18.0% to 14.8%, p<0.001). Individual-level DBM (concurrent stunting with overweight/obesity) was uncommon (<0.2%). City-level heterogeneity was marked, with Haiphong showing the highest male obesity (22.7% in 2025) and individual-level DBM. Conclusion: Vietnamese urban schoolchildren experienced simultaneous, divergent nutritional burdens from 2018-2025: rising stunting and thinness under age 10, declining early childhood obesity, and rising adolescent male obesity. Individual-level DBM was rare, but a population-level double burden was evident across age groups. City, age, and sex specific nutrition and school health policies are needed to address this complex malnutrition transition.