Association Between Triglyceride‐Glucose‐Body Mass Index and Depression in Elderly Diabetic Individuals: A Population‐Based Study

Background Although the association between insulin resistance (IR) and depression has been extensively studied, the relationship between triglyceride‐glucose‐body mass index (TyG‐BMI) and depressive symptoms in elderly patients with diabetes remains unclear. This study aimed to investigate the association between TyG‐BMI and depression risk in older adults with diabetes using data from the National Health and Nutrition Examination Survey (NHANES). Methods This retrospective cross‐sectional study included a total of 2584 participants aged ≥ s65 years with diabetes from NHANES (2005–2018). Depression was assessed using the Patient Health Questionnaire‐9 (PHQ‐9), with a score ≥ 10 defining clinically significant depression. Multivariable logistic regression and restricted cubic spline models were employed to analyze the TyG‐BMI–depression association, adjusting for sociodemographic, lifestyle, and disease‐related covariates. In addition, subgroup analyses were also conducted. Results Participants in the highest TyG‐BMI quartile (Q4: > 314.04) exhibited a significantly higher risk of depression compared to the lowest quartile (Q1: < 232.44), with an adjusted odds ratio (OR) of 2.972 (95% CI: 1.264–6.988). A dose‐response analysis revealed a linear positive relationship between TyG‐BMI and depression risk ( p for nonlinearity = 0.066). Subgroup analyses showed no significant interactions by gender, education level, or other stratification factors (all p > 0.05). Conclusion Elevated TyG‐BMI is independently associated with increased depression risk in elderly diabetic patients, highlighting its potential as a biomarker for metabolic‐psychiatric comorbidity. Further studies are warranted to validate TyG‐BMI’s utility in early depression screening and intervention strategies.