Sex-Specific Associations of the Triglyceride-Glucose Index With Systemic Inflammation and Arterial Stiffness in Adults With Normal Glucose and Triglyceride Levels

The triglyceride-glucose (TyG) index is a surrogate marker of insulin resistance. However, its clinical relevance in individuals with strictly normal fasting glucose and triglyceride levels remains unclear. We aimed to investigate the sex-specific associations of the TyG index with systemic inflammation and arterial stiffness among adults with normal fasting glucose and triglyceride levels. This cross-sectional study included 2,574 apparently healthy adults (1,300 males and 1,274 females) with fasting plasma glucose <100 mg/dL and triglycerides <150 mg/dL. Elevated systemic inflammation was defined as high-sensitivity C-reactive protein (hsCRP) >3.0 mg/L, and increased arterial stiffness as brachial-ankle pulse wave velocity (baPWV) ≥1,400 cm/s. Sex-stratified multivariable logistic regression was used to evaluate these associations across TyG quartiles. In females, higher TyG quartiles were independently associated with both outcomes. Compared with the lowest quartile (Q1), adjusted odds ratios (AORs) in females for elevated hsCRP were 2.44 (95% CI, 1.36–4.39) for Q3 and 2.95 (1.65–5.29) for Q4. For increased arterial stiffness, AORs in females were 2.46 (1.34–4.53), 2.39 (1.31–4.36) and 2.44 (1.34–4.45) for Q2–Q4, respectively. Conversely, no significant independent associations were identified in males across all quartiles. A significant sex-interaction was observed for elevated hsCRP (p <0.001). Among adults with normal fasting glucose and triglyceride levels, a higher TyG index is independently associated with subclinical inflammation and arterial stiffness, predominantly in females. These findings suggest that the TyG index may help identify early cardiometabolic vulnerability in women even within conventionally normal metabolic ranges.