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Original Article

Anthropometric trajectories of Korean children and adolescents with severe obesity

Jeongho Han¹  , Hakyung Lee¹  , Dong Jun Ha¹  , Jieun Lee²  , Yong Hee Hong³  , Hwa Young Kim^1,4  , Jaehyun Kim^1,4 

¹Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, Korea
²Department of Pediatrics, Inje University Ilsan Paik Hospital, Goyang, Korea
³Department of Pediatrics, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea
⁴Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea

Correspondence Jaehyun Kim ,Email: jaehyun.kim@snu.ac.kr

Received: December 28, 2025; Revised: February 2, 2026   Accepted: February 12, 2026.

Abstract

Background
The burden of severe pediatric obesity is increasing globally, including in South Korea, and associated with metabolic and cardiovascular complications. However, longitudinal data of Korean children with severe obesity are limited.
Purpose
This study evaluated the changes in body mass index (BMI) and associated metabolic syndrome components in children and adolescents with severe obesity managed without pharmacological or surgical treatment.
Methods
We retrospectively reviewed participants diagnosed with severe obesity (BMI ≥120% of the 95th percentile) before the age of 18 years at 3 medical centers in 2017–2024. Participants with more than 1 year of follow-up were included. Management consisted exclusively of lifestyle modifications, including nutritional counseling and physician-led education on physical activity, screen time, and sleep. Patients with chronic illnesses, with psychiatric disorders, or who were taking medications that affect weight were excluded. The primary outcome was the change in BMI z score from baseline to the last visit. Predictors of a change in the BMI z score were analyzed using multivariable linear regression with adjustment for age, sex, pubertal stage, baseline BMI z score, and follow-up duration and frequency.
Results
Among 124 participants (mean age, 9.69±3.39 years; 61.3% boys) followed for a mean duration of 2.64±1.51 years, BMI z scores significantly decreased (from 3.68±0.75 to a mean change of -0.27±0.79, P<0.001). Younger age and male sex were associated with greater reductions in BMI z scores. However, most participants remained severely obese. Except for modest improvements in liver transaminase levels, no substantial differences were observed in other metabolic syndrome components.
Conclusion
Lifestyle modification resulted in a modest BMI z score reduction; however, most participants remained severely obese with no significant improvements in most metabolic syndrome components. These findings underscore the need for early and intensive interventions for pediatric obesity.

Keywords :Pediatric obesity, Morbid obesity, Body-weight trajectory, Metabolic syndrome, Body composition