This study aims to assess the changes in nutritional status amongstudents aged 11 to 14 at Thanh Thuy Secondary School, Hanoi, over threeconsecutive years (2021 to 2023). The study involved a total of 606 students in2021, 638 in 2022, and 694 in 2023. Nutritional status was evaluated based onWHO 2007 guidelines using the WHO AnthroPlus software. Results showed astatistically significant decline in median height from 152 cm in 2021 to 150 cm in2022 and 2023 (P = 0.036), indicating a decrease in physical stature. Thepercentage of students with normal nutritional status decreased from 75.4% in 2021to 69.2% in 2023. Concurrently, moderate thinness increased from 9.6% to 13.3%,and severe thinness rose from 1.5% to 3.2%. Overweight prevalence remainedstable at around 11%, while obesity slightly increased from 2.1% to 2.7%. Theoverall prevalence of malnutrition significantly increased from 24.6% in 2021 to 33%in 2023 (P <
0.05), primarily due to a significant rise in undernutrition, which rosefrom 11.1% in 2021 to 17.6% in 2023 (P <
0.05). For 11-year-olds, overweightprevalence significantly decreased (P <
0.001), while moderate thinnesssignificantly increased (P = 0.037). Among 12- and 13-year-olds, significantincreases in moderate thinness and overweight were observed. These findingsunderscore the growing issue of the double burden of malnutrition and highlightthe need for targeted nutritional interventions among school-aged children.This study aims to assess the changes in nutritional status amongstudents aged 11 to 14 at Thanh Thuy Secondary School, Hanoi, over threeconsecutive years (2021 to 2023). The study involved a total of 606 students in2021, 638 in 2022, and 694 in 2023. Nutritional status was evaluated based onWHO 2007 guidelines using the WHO AnthroPlus software. Results showed astatistically significant decline in median height from 152 cm in 2021 to 150 cm in2022 and 2023 (P = 0.036), indicating a decrease in physical stature. Thepercentage of students with normal nutritional status decreased from 75.4% in 2021to 69.2% in 2023. Concurrently, moderate thinness increased from 9.6% to 13.3%,and severe thinness rose from 1.5% to 3.2%. Overweight prevalence remainedstable at around 11%, while obesity slightly increased from 2.1% to 2.7%. Theoverall prevalence of malnutrition significantly increased from 24.6% in 2021 to 33%in 2023 (P <
0.05), primarily due to a significant rise in undernutrition, which rosefrom 11.1% in 2021 to 17.6% in 2023 (P <
0.05). For 11-year-olds, overweightprevalence significantly decreased (P <
0.001), while moderate thinnesssignificantly increased (P = 0.037). Among 12- and 13-year-olds, significantincreases in moderate thinness and overweight were observed. These findingsunderscore the growing issue of the double burden of malnutrition and highlightthe need for targeted nutritional interventions among school-aged children.