The association between triglyceride glucose index-related indices and depression among adults in the United States: NHANES 2005–2018

Background It has been established that the triglyceride-glucose (TyG) index is associated with depression. Nonetheless, it remains unclear whether combining TyG with obesity indices could show a stronger association with depression. Methods Based on the 2005–2018 National Health and Nutrition Examination Survey (NHANES), this large cross-sectional study analyzed a total of 14,821 adults. Four main indices were used in the present study: the TyG index, TyG-WC (with waist circumference), TyG-WHtR (with waist-to-height ratio), and TyG-BMI (with body mass index). Using logistic regression, restricted cubic splines (RCS), and stratified analysis, we rigorously examined the association between TyG-related indices and symptoms of depression. Diagnostic values were assessed using receiver operating characteristic (ROC) curves. Finally, sensitivity analyses were performed to determine whether the association was robust and consistent. Results A positive association was identified between TyG, TyG-WHtR, TyG-WC, and TyG-BMI and depression. This association is particularly pronounced among women, individuals with higher education levels, and those with hypertension and diabetes. Compared to the other three indices, TyG-WHtR demonstrated the most significant association with depression after adjusting for all covariates (odds ratio (OR):1.21, 95% confidence interval (CI):1.07–1.37). ROC curves indicated that TyG-WHtR had the highest diagnostic efficacy (AUC: 0.601, 95% CI 0.575–0.610). Sensitivity analyses consistently confirmed the robustness and reliability of the association between TyG-related indices and depressive symptoms. Conclusions Among American adults, TyG-WC, TyG-WHtR, and TyG-BMI showed a positive and non-linear association with depressive symptoms. Furthermore, our analysis revealed that TyG-WHtR offered superior precision and sensitivity in evaluating this association compared to TyG alone, TyG-WC, and TyG-BMI.