Abstract
Abdominal obesity and related cardiometabolic risk (CMR) factors frequently begin in adolescence and contribute to long‑term health burden, yet longitudinal trajectories in U.S. youth are poorly characterized. This study quantifies the prevalence and 2‑ and 4‑year incidence of emerging CMR, with emphasis on excess adiposity, in a diverse adolescent cohort. We analyzed longitudinal data from the Adolescent Brain Cognitive Development Study, collected at three time points: 2018-2020 (mean age, 12.1 years), 2020-2022 (mean age, 14.2 years), and 2022-2024 (mean age, 16.1 years). Adolescents (n = 4788 to 3313) with anthropometric and laboratory data were included. Abdominal obesity was defined as a waist-to-height ratio > 0.5. Additional CMR factors included elevated total cholesterol (≥ 145 mg/dL), glycated hemoglobin (HbA1c ≥ 5.7%), and high blood pressure (≥ 95th percentile for age, sex, and height). Weighted prevalence and 2- and 4-year incidence were calculated. At baseline, abdominal obesity affected 38.4% (95% CI: 36.4%-40.4%), followed by elevated cholesterol (17.6%), HbA1c (8.7%), and blood pressure (3.0%). Over a four-year period, new-onset abdominal obesity occurred in 10.5% of individuals, compared with 15.4% for cholesterol, 4.7% for HbA1c, and 3.1% for blood pressure. The steepest CMR progression was observed for lipid and adiposity markers. Abdominal obesity is highly prevalent by early adolescence, and new cardiometabolic risk develops rapidly, particularly for adiposity and dyslipidemia. These results highlight the need for early obesity screening and interventions to mitigate long‑term cardiometabolic risk in youth.