Sex-Specific Associations of Childhood BMI Patterns with Cardiometabolic Risk: An 11-Year Korean Longitudinal Study

<b>Background/Objectives:</b> Childhood overweight/obesity status is a critical risk factor for adverse cardiometabolic outcomes. We aimed to evaluate the sex-specific associations between a maintained childhood overweight status and late-adolescent cardiometabolic risk factors using data from a Korean longitudinal study. <b>Methods</b>: We used data from the Korean Children-Adolescents Study, a prospective cohort of children enrolled at age 7 and followed annually from 2005 to 2020. Among participants who were followed at least once, a total of 899 children (438 boys, 461 girls) with consistent body mass index (BMI) status at ages 7-9 and 10-12 were included in the analysis. Participants were categorized into two groups on the basis of BMI: normal weight maintenance and overweight maintenance. Multivariable linear regression was used to examine the associations between BMI patterns and cardiometabolic risk factors, with adjustments for covariates. <b>Results</b>: Among the 899 children (mean age: 7.1 ± 0.4 years, 48.7% boys), 12.8% of boys and 5.9% of girls were classified into the overweight maintenance group. Boys in the overweight maintenance group had significantly greater BMIs, waist circumferences (WC), body fat percentages, trunk fat mass, and aspartate aminotransferase and alanine aminotransferase levels at ages 15 and 18. Girls in the same group had elevated BMI, WC, body fat percentage, trunk fat mass, and blood pressure and experienced earlier pubertal onset. <b>Conclusions</b>: Maintaining an overweight status during childhood is associated with adverse cardiometabolic profiles in adolescence, with sex-specific differences. These findings highlight the importance of early, sex-specific interventions to prevent long-term health risks associated with childhood obesity.