Association of triglyceride-glucose index with carotid atherosclerosis in the general population: a case-control study of 14,535 participants

Atherosclerotic cardiovascular disease (ASCVD) remains a leading cause of death worldwide, with increased carotid intima-media thickness (CIMT) and carotid plaque serving as key markers of subclinical atherosclerosis. The triglyceride glucose (TyG) index, a surrogate for insulin resistance, is linked to cardiovascular risk, but its association with carotid atherosclerosis remains unclear. This study explored the relationship between the TyG index and carotid plaque and increased CIMT in general population. We screened 30,084 participants who received health check-ups at Aerospace Center Hospital between January and December 2019. The TyG index was calculated as Lnfasting triglyceride (mg/dL) × fasting blood glucose (mg/dL)/2. Carotid ultrasound assessed CIMT and plaque. Logistic regression and restricted cubic splines were used to examine the associations of TyG index with carotid atherosclerosis, adjusting for confounders. Fourteen thousand five hundred thirty-five participants were included in the final analysis. In multivariable logistic regression, the highest TyG index quartile (Q4) was significantly associated with greater odds of carotid plaque compared to normal CIMT (OR = 1.345; 95% CI: 1.098–1.648; P = 0.004) and increased CIMT (OR = 1.342; 95% CI: 1.067–1.689; P = 0.012), after adjustment for confounders. Restricted cubic spline analysis confirmed a significant nonlinear association between the TyG index and carotid plaque versus normal CIMT (P < 0.001), and a linear association versus increased CIMT (P = 0.002). No independent association was observed between the TyG index and increased CIMT versus normal CIMT. Age-stratified analyses showed significant associations between the TyG index and carotid plaque as compared with normal CIMT in individuals aged 40–69 years, and with increased CIMT in those aged 50–69 years (P < 0.05). The association with carotid plaque remained significant in both sexes. The TyG index is independently associated with carotid plaque but not increased CIMT, particularly in individuals aged 40–69 years. These findings suggest that the TyG index may serve as a useful biomarker for identifying subclinical atherosclerosis, especially in middle-aged individuals.