The Impact of Triglyceride-Glucose Index on Carotid Atherosclerosis: A Prospective Cohort Study in Middle Aged and Elderly Low-Income in Rural Chinese

Background: Atherosclerotic cardiovascular disease (ASCVD) is a major global health burden. The triglyceride-glucose (TyG) index, as a surrogate marker of insulin resistance, is associated with atherosclerosis, but its role in predicting carotid plaque and intima-media thickness (IMT) changes remains unclear. This study aimed to assess the relationship between the TyG index and carotid plaque incidence and IMT changes over a six-year period in a cohort of middle-aged and elderly individuals with low income and low education in rural China. Methods: The study was conducted from 2014 to 2020 in 18 rural villages in Tianjin, China. A total of 2702 participants were included in the IMT analysis, and after excluding those with carotid plaques at baseline, 1595 participants were included in the plaque incidence analysis. Multivariate logistic regression was used to assess the relationship between the TyG index and outcomes. Subgroup analyses were based on significant indicators from the multivariate adjustment. Results: During the six-year follow-up, 551 new cases of carotid plaque were identified, with an incidence rate of 34.5%. Univariate analysis showed a significant association between the TyG index and increased plaque incidence. However, after adjusting for multiple confounders, the TyG index emerged as an independent predictor only for IMT increase. Each 1-unit increase in TyG was associated with a 49% increased risk (RR: 1.49; 95% CI: 1.05-2.13; P = 0.026), with this association being particularly strong in males, individuals aged ≥60 years, and those without hypertension. Conclusion: Results highlight the importance of incorporating the TyG index into cardiovascular risk assessments, especially for IMT changes in specific subpopulations. The study underscores the need for targeted prevention strategies in rural, low-education and low-income populations. Future research is needed to elucidate the potential interactions between the TyG index and other metabolic factors in ASCVD.