The Relationship between Vitamin D and TyG Index in Prediabetes and Type 2 Diabetes Mellitus among an Indian Tribal Community: A Cross-Sectional Study

Background: Vitamin D deficiency is thought to increase the likelihood of insulin resistance (IR) and diabetes onset. The objective of this study was to examine the association between the triglyceride glucose (TyG) index and vitamin D levels in individuals with prediabetes and type 2 diabetes mellitus (T2DM) in the tribal community of India. Methods: This study included 270 participants, consisting of 90 individuals with prediabetes, 90 individuals with T2DM, and 90 control patients. Anthropometric and biochemical characteristics were evaluated in all participants. 25-hydroxyvitamin D [25(OH)D] levels were measured using a chemiluminescent immunoassay. The TyG index was computed as Ln [fasting triglycerides (mg/dL) × fasting glucose (mg/dL)]/2. Spearman correlation analysis and linear regression analysis were performed to assess the relationship between the TyG index and 25(OH)D levels in people diagnosed with prediabetes and T2DM. The optimum cut-off value of the TyG index for detecting vitamin D deficiency was determined by receiver operating characteristic (ROC) curve analysis. Results: We observed a significant reduction in vitamin D levels in individuals with prediabetes and T2DM compared to those in the control group. However, the TyG index was significantly greater in individuals with prediabetes and T2DM than in controls. Statistical analysis revealed a significant negative correlation between the TyG index and 25(OH)D in both prediabetes and T2DM. Conclusions: The TyG index demonstrated a negative association with vitamin D levels and was identified as an independent predictor of vitamin D deficiency in individuals with prediabetes and T2DM.