Different risk factors for elevated blood pressure according to abdominal obesity in overweight children and adolescents

BACKGROUND: The increasing hypertension (HTN) prevalence in children, largely driven by obesity, highlights the need to investigate its risk factors, including the role of abdominal obesity. METHODS: We analysed data from the Korea National Health and Nutrition Examination Survey (2007-2021) to assess the prevalence of overweight and obesity (OW-OB), elevated blood pressure (EBP), and HTN among 11,554 participants aged 10-18 years. EBP and HTN were defined according to the 2017 American Academy of Pediatrics guidelines, and abdominal obesity was defined as a waist-to-height ratio (WHtR) of ≥ 0.5. Secular trends in the prevalence of OW-OB and EBP-HTN were examined across five time periods, and risk factors for EBP-HTN were evaluated in OW-OB children stratified by abdominal obesity status. RESULTS: The prevalence of EBP, HTN, and OW-OB was 8.22% (95% confidence interval [CI], 7.60-8.86), 10.46% (95% CI, 9.72-11.20), and 25.11% (95% CI, 24.17-26.05), respectively. Among the 3,015 participants with OW-OB, 13.53% (95% CI, 12.03-15.04) and 17.64% (95% CI, 15.98-19.31) were diagnosed with EBP and HTN, respectively. Although the prevalence of OW-OB and EBP-HTN had increasing trends from 2007 to 2009 to 2019-2021, these trends were not statistically significant. In the children with OW-OB, obesity severity, male sex, older age, and paternal HTN were associated with EBP-HTN. The HTN risk factors differed according to abdominal obesity status. In participants with abdominal obesity, male sex (OR 2.32, 95% CI 1.643-3.299; p < 0.0001), older age (OR 1.16, 95% CI 1.102-1.233; p < 0.0001), and severe obesity (OR 3.12, 95% CI 1.991-4.895; p < 0.0001) were significant risk factors; whereas, in those without abdominal obesity, paternal HTN (OR 1.66, 95% CI 1.207-2.303; p = 0.0025), hypercholesterolemia (OR 1.85, 95% CI 1.114-3.083; p = 0.0178), male sex (OR 1.83, 95% CI 1.329-2.530; p = 0.0002), and older age (OR 1.11, 95% CI 1.036-1.198; p = 0.0038) were significant risk factors. CONCLUSIONS: In children with overweight or obesity, the risk factors for EBP-HTN vary depending on the presence of abdominal obesity. These findings highlight the need for differentiated surveillance and prevention strategies based on abdominal obesity status in this high-risk population. CLINICAL TRIAL NUMBER: Not applicable.