Assessment of BMI percentages of obesity thresholds and cardiometabolic risk factors in children and adolescents: a retrospective cross-sectional study in Beijing

The prevalence of pediatric obesity, particularly severe obesity, is rising rapidly in China. Few studies have examined the relationship between body mass index (BMI) expressed as percentages of obesity thresholds (%BMI) and cardiometabolic risks in Chinese pediatric population. This study aims to evaluate the dose-response relationship between %BMI and cardiometabolic risk factors among children and adolescents in Beijing. This retrospective cross-sectional study utilized electronic health records (EHRs) of children and adolescents aged 7–18 years with obesity attending a specialized clinic. Anthropometric and laboratory data were extracted and validated. Individuals were categorized into class 1 obesity (BMI 100–120% of the obesity thresholds), class 2 (120–140%), and class 3 (≥ 140%). Logistic regression assessed the associations between obesity subcategories and four cardiometabolic risk factors, including prediabetes, dyslipidemia, insulin resistance (IR), and elevated liver enzymes. Restricted cubic spline (RCS) models were used to investigate the dose-response relationship between %BMI and cardiometabolic risk factors. Among 1,761 included individuals, class 3 obesity was associated with significantly higher odds of prediabetes (OR = 1.49 [95% CI: 1.01–2.19] for boys; OR = 2.91 [95% CI: 1.57–5.41] for girls), IR (OR = 4.40 [95% CI: 2.66–7.51] for boys; OR = 3.52 [95% CI: 1.63–8.35] for girls), and elevated liver enzymes (OR = 2.65 [95% CI: 1.81–3.93] for boys; OR = 2.97 [95% CI: 1.65–5.47] for girls) compared to class 1. Linear dose-response relationships were observed between %BMI and these factors. Dyslipidemia and its components (e.g., low high-density lipoprotein cholesterol and high triglyceride) exhibited complex dose-response relationships that varied by sex and Tanner Stage. Among obese children and adolescents in Beijing, higher %BMI might be linearly associated with greater likelihood of prediabetes, IR, and elevated liver enzymes, while dyslipidemia exhibits sex- and puberty-specific patterns. Further researches are required to characterize cardiometabolic risks across the obesity spectrum in Chinese pediatric population to inform targeted interventions.