TyG index (triglyceride-glucose index)

The TyG index is a surrogate marker for insulin resistance calculated as ln(fasting triglycerides [mg/dL] × fasting glucose [mg/dL] ÷ 2). Proposed by Simental-Mendía et al. in 2008, it approximates hyperinsulinemic-euglycemic clamp measurements without an insulin assay. The index reflects impaired triglyceride clearance and elevated hepatic glucose output, hallmarks of insulin resistance in adipose and liver tissue. Insulin resistance accelerates atherosclerosis, promotes visceral adiposity, and contributes to β-cell exhaustion; elevated TyG values are independently associated with biological aging phenotypes. A 2022 meta-analysis (12 cohorts, n ≈ 6.4 million) found the highest TyG quartile carried roughly doubled coronary artery disease risk (HR 2.01; 95% CI 1.68–2.40) and 46% higher composite CVD risk; mortality associations were weaker and heterogeneous. A 2023 Swedish cohort analysis (Malmö Diet and Cancer Study, Malmö Preventive Project) showed TyG increments predicted arterial stiffness, 3.3-fold diabetes incidence (top vs. bottom quartile), and higher all-cause (HR 1.22) and cardiovascular mortality (HR 1.37). All evidence is observational; TyG-guided interventions remain untested in randomized trials, and the index performs best in non-diabetic, insulin-naïve populations.