Triglyceride-glucose indices distinguish clinical from preclinical obesity in US adults: A cross-sectional study

Obesity is a heterogeneous metabolic condition with individuals exhibiting varying risks of obesity-related complications. The triglyceride-glucose (TyG) and TyG-related indices are surrogate markers of insulin resistance and may reflect differences across obesity phenotypes. Whether these indices distinguish between clinical obesity phenotype (excess body fat, accompanied by obesity-related complications) and preclinical obesity phenotype (excess body fat, without obesity-related complications) remains unclear. This study aimed to examine the association of TyG and TyG-related indices with obesity phenotypes and metabolic risks in US adults. Data from 4532 adult participants from the National Health and Nutrition Examination Survey 2011 to 2020 were analyzed. Obesity phenotypes were classified based on excess body fat with or without obesity-related complications. Survey-weighted logistic regression models with progressively adjusted models including demographic, behavioral, socioeconomic and medication use assessed associations of TyG and TyG-body mass index, TyG-waist circumference, TyG-waist-to-height ratio, and homeostatic model assessment for insulin resistance with clinical obesity phenotype. Model discrimination was assessed using receiver operating characteristic analysis. The weighted prevalence of clinical obesity phenotype was 60.2% among individuals with excess body fat, with affected individuals more likely to be older males with higher anthropometric measurements. The TyG-related indices and homeostatic model assessment for insulin resistance values were significantly higher. In progressively adjusted models, TyG-related indices remained associated with clinical obesity, with the highest odds observed for TyG-body mass index (OR = 1.60), whereas TyG index was no longer significant in the fully adjusted model. TyG and TyG-related indices were associated with clinical obesity phenotype in US adults with excess adiposity. These markers may provide complementary information for risk stratification, although their independent discriminatory value appeared modest.