Research on Body Composition and Lifestyle Behaviors During Pubertal Development in 6–12-Year-Old Children with Obesity

<b>Objective:</b> The objective of this study was to investigate the pubertal development in school-age children with obesity and to explore the body composition and lifestyle behaviors influencing its onset. <b>Method:</b> We enrolled 217 children, aged 6-12 years, who visited the Pediatrics Department at Beijing Jishuitan Hospital, Capital Medical University. All participants underwent a series of examinations. These assessments included body composition analysis, measurement of blood glucose and fasting insulin levels, and evaluation of secondary sexual characteristics. Statistical analysis was conducted using R4.0.3 software. <b>Results:</b> Of the 152 male participants, 83 (54.6%) were in the adolescent-undeveloped group, and 69 (45.4%) were in the adolescent-developed group. Of the 119 female students, 30 (25.2%) were in the adolescent-undeveloped group, and 89 (74.8%) were in the adolescent-developed group. In a comparative analysis of children, those in the adolescent development group exhibited significantly higher values for age, height, weight, body mass index (BMI), BMI-z score, body fat, muscle mass, fat-free weight, fat-free body mass index, and waist/hip ratio compared to the adolescent-undeveloped group (<i>p</i> < 0.05). Additionally, fasting insulin and insulin resistance index were also higher in the development group, with statistical significance observed. BMI emerged as an independent factor affecting the adolescent development of school-age girls with obesity (<i>p</i> < 0.05). Among boys in the adolescent development group, the consumption of sugary drinks and fried food was higher than in the undeveloped group, and moderate-intensity exercise was significantly lower, with statistical significance (<i>p</i> < 0.05). In girls, the adolescent development group reported longer daily sitting times and higher intakes of sugary drinks and fried foods compared to the undeveloped group, with these differences being statistically significant (<i>p</i> < 0.05). The consumption of fried food was positively correlated with adolescent development in children with obesity and was identified as an independent influencing factor of adolescent development (<i>p</i> < 0.05). <b>Conclusions:</b> A high body mass index (BMI) in girls with obesity and high intake of fried foods in both genders are strong predictors of early puberty in school-age children.