Abstract Body (Do not enter title and authors here): Background: The triglyceride-glucose index (TyG), an inexpensive novel surrogate marker for insulin resistance, and lipoprotein (a) [Lp(a)] are both risk factors for atherosclerotic cardiovascular disease (ASCVD). However, it is uncertain whether TyG modifies the relationship of Lp(a) with incident ASCVD.
Objective: To investigate the relationship of Lp(a) and TyG with the risk of incident ASCVD.
Methods: We included UK Biobank participants without ASCVD at enrollment. Baseline TyG was calculated as ln[fasting triglycerides (mg/dL) × fasting plasma glucose (mg/dL)/2]. We classified TyG values as high (≥75th percentile) or low (<75th percentile), and Lp(a) levels, in nmol/L, as <125 or ≥125. Participants were then stratified into four groups: Group-1: Low TyG with Lp(a), <125, Group-2: Low TyG with Lp(a) ≥125, Group-3: High TyG with Lp(a) <125, and Group-4: High TyG with Lp(a) ≥125. We used multivariable Cox regression to estimate the risk of ASCVD (a composite of peripheral arterial disease, coronary artery disease, myocardial infarction, ischemic stroke, and cardiovascular mortality) of TyG and Lp(a) adjusted for the other, and in the four combination groups.
Results: Eligible participants (N=254,377) had a mean (SD) age of 56.0 (8.1) years, and 53.2% were female. The median follow-up was 14.6 years. In separate models additionally adjusted for cardiovascular risk factors (see Figure legend), the hazard ratio (HR [95% CI]) for ASCVD was 1.18(1.13–1.23) for Lp(a) ≥125 nmol/L (vs. <125 nmol/L), adjusted for TyG, and 1.09(1.05–1.13) for high TyG (vs. low), adjusted for Lp(a). A statistically significant interaction between TyG and Lp(a) was observed in the fully adjusted model (p <0.001). Compared to Group-1 (low TyG with Lp(a) <125nmol/L), the adjusted HR (95% CI) of incident ASCVD in Group-2, -3 and -4 were: 1.07(1.04–1.13), 1.15 (1.09–1.21) and 1.34(1.25–1.44), respectively (Figure).
Conclusions: These findings demonstrate that TyG and Lp(a) are associated with incident ASCVD risk independently of each other. Moreover, TyG modified the effect of Lp(a) on ASCVD, suggesting that insulin resistance may amplify the atherogenic, inflammatory, and/or thrombotic effects of Lp(a), thereby further increasing ASCVD risk.