5174 A longitudinal retrospective cohort study on the application of the Superimposition by translation and rotation (SITAR) model to estimate body composition growth trajectory in Korean children and adolescents during puberty

Abstract Disclosure: S. Kim: None. S. Kim: None. J. Suh: None. Introduction: In addition to adulthood, pediatricians have noted a growing emphasis on research concerning sarcopenic obesity. Studies in this field have expanded beyond basic BMI-related inquiries, actively delving into investigations based on body fat mass (BFM) and fat-free mass (FFM). However, limited research has systematically analyzed the acquisition of body composition during children and adolescence based on longitudinal data. Objective: This study aims to assess the acquisition of weight, FFM, and BFM during the pubertal growth of Korean children and adolescents. Methods: This study utilized mixed longitudinal body measurement and body composition data, employing bioelectrical impedance analysis, from 4,641 height measurements (2,204 for boys and 2,437 for girls) obtained from 361 individuals (170 boys and 191 girls) among Korean children and adolescents aged 7 to 18. The SITAR (the Superimposition by Translation and Rotation) model, a shape-invariant growth curve model, was used to estimate a reference height velocity curve during pubertal growth. Results: The SITAR methodology allowed us to investigate the timing, magnitude, and intensity of adolescent weight, FFM, and BFM gain. The results revealed significant differences in growth trajectories between boys and girls, with boys exhibiting a persistent elevation in FFM and a pattern of ascent followed by a decline in BFM, while girls show an increase in BFM and a deceleration in FFM growth. In Korean boys, the peak weight velocity (PWV) occurred at a mean age of 12.41 years, with a rate of 8.19 kg/year. Peak fat-free mass velocity (PFV) was observed at a mean age of 9.69 years, with a rate of 7.60 kg/year, and peak body fat mass velocity (PBV) at a mean age of 12.70 years, with a rate of 2.67 kg/year. In Korean girls, the mean age of PWV was 11.28 years, with a velocity of 6.33 kg/year. PFV occurred at a mean age of 12.33 years, with a rate of 4.86 kg/year, and PBV at a mean age of 11.13 years, with a rate of 2.72 kg/year. The ages of peak velocities of height (PHV), PWV, PFV, and PBW positively correlated. Conclusions: This study is the first to apply the SITAR model to examine the acquisition of body composition in Korean children and adolescents. Future research should delve into exploring the connections between various disease groups during childhood and adolescence and the patterns of change in body composition. Presentation: 6/1/2024