The Relationship between the Triglyceride-Glucose Index and Vitamin D Levels in American Adults

Original Research Articles The Relationship between the Triglyceride-Glucose Index and Vitamin D Levels in American Adults Ishwarlal Jialal 1,* and Beverley Adams-Huet 2 1 Retired Distinguished Professor of Internal Medicine and Pathology, UC Davis School of Medicine, 2616 Hepworth Drive, Davis, CA 95618, USA 2 UT Southwestern Medical Center, Dallas, TX 75390, USA * Correspondence: [email protected]; Tel.: +1-530-902-0125 Received: 16 December 2024; Accepted: 28 December 2024; Published: 1 March 2025 Abstract: The triglyceride-glucose (TyG) index is a cost-effective, reliable and validated measure of insulin resistance. Furthermore it is a promising biomarker of Metabolic Syndrome (MetS), Type-2 Diabetes (T2DM) and premature atherosclerotic cardiovascular diseases (ASCVD). Although groups from numerous countries especially Asia have shown an inverse relationship between Vitamin D levels and the TyG index, there is a severe paucity of data by US investigators. Accordingly, in the present preliminary report we investigated the relationship between tertiles of TyG index and Vitamin D levels and also undertook correlations with relevant variables. The TyG index increased significantly over tertiles in the combined group of MetS (n = 41) and controls (n = 37). However there was no significant change in plasma Vitamin D levels over tertiles, p = 0.15. We show a modest but significant correlation between TyG and Vitamin D. In conclusion in this pilot study we failed to see a significant decrease in Vitamin D levels over increasing tertiles of the TyG index but showed a modest inverse correlation. Hence future studies with much larger sample sizes of American participants can settle this important issue.