Beyond conventional lipid panel: Estimated small dense and triglyceride-rich LDL cholesterol are associated with prediabetes independently of obesity in adolescents.

BACKGROUND: Childhood obesity is strongly associated with insulin resistance and atherogenic dyslipidemia. Novel lipid indices such as small dense low-density lipoprotein cholesterol (sdLDL-C) and triglyceride-rich LDL (LDL-TG), along with the triglyceride-glucose (TyG) index, may improve early detection of metabolic risk, but their role in adolescents remains unclear. OBJECTIVE: To evaluate the association of calculated lipid indices (sdLDL-C, LDL-TG) and the TyG index with adiposity and prediabetes, and to assess their discriminative performance beyond conventional lipid parameters. METHODS: We conducted a retrospective cross-sectional study including 1302 adolescents aged 10 to 19 years. Participants were classified by body mass index (BMI) category. Calculated lipid indices and TyG were derived from routine laboratory data. Multinomial logistic regression assessed associations with overweight and obesity. A matched case-control analysis (n = 154 pairs) evaluated independent associations with prediabetes, including a secondary model matched for LDL-C. Discriminative ability was assessed using receiver operating characteristic curves. RESULTS: All metabolic markers increased progressively with BMI (P < .001). The TG/high-density lipoprotein cholesterol (HDL-C) ratio showed the strongest association with obesity (standardized OR 7.17). In matched analyses, TyG, sdLDL-C, LDL-TG, and TG/HDL-C were independently associated with prediabetes. In the LDL-C matched model, TyG remained strongly associated (P < .001), while sdLDL-C and LDL-TG retained independent associations. TyG showed the highest discriminative ability for prediabetes (areas under the curve [AUC] 0.678); sdLDL-C, LDL-TG, and TG/HDL-C showed comparable, more modest discriminative power (AUC 0.586-0.601). CONCLUSION: Calculated lipid indices capture early atherogenic lipoprotein remodeling in adolescents, independently of adiposity and LDL-C. While TyG is the strongest marker of glucose dysregulation, lipid-derived indices provide complementary information on cardiometabolic risk. These accessible markers may provide complementary, independent information for early risk stratification using routine laboratory data.