Vitamin E intake mediates the associations of triglyceride-glucose index and its related parameters with phenotypic age acceleration in middle-aged and elderly population.

The triglyceride-glucose (TyG) index and vitamin E intake have been demonstrated to be associated with various health outcomes. However, the relationship between the TyG and its obesity-related metrics with accelerated phenotypic aging, as well as the potential mediating role of vitamin E intake, remain unclear. Our study included 3114 participants from the National Health and Nutrition Examination Survey (NHANES). Weighted linear regression and logistic regression analyses were performed to examine the associations of TyG and its related indicators (triglyceride glucose-waist to height ratio [TyG-WHtR], triglyceride glucose-body mass index [TyG-BMI], and triglyceride glucose-body roundness index [TyG-BRI]) with phenotypic age acceleration (PhenoAgeAccel) and accelerated aging, respectively. Mediation analysis was performed to evaluate the mediating role of vitamin E intake in the associations between these parameters with PhenoAgeAccel. The diagnostic value of these indices for accelerated aging was evaluated using receiver operating characteristic (ROC) curve analysis. 27.71% of participants were classified as experiencing accelerated aging. TyG and its related indicators were all significantly positively associated with PhenoAgeAccel (TyG: β = 2.67, 95% confidence interval [CI]: 2.27, 3.07; TyG-WHtR: β = 1.87, 95% CI: 1.61, 2.13; TyG-BMI/100: β = 2.59, 95% CI: 2.20, 2.99; TyG-BRI/10: β = 0.80, 95% CI: 0.67, 0.93). Furthermore, all metrics were positively correlated with accelerated aging (TyG: odds ratio [OR] = 2.00, 95% CI: 1.63, 2.46; TyG-WHtR: OR = 1.85, 95% CI: 1.59, 2.15; TyG-BMI/100: OR = 2.46, 95% CI: 1.95, 3.11; TyG-BRI/10: OR = 1.30, 95% CI: 1.21, 1.40). In addition, both PhenoAgeAccel and the risk of accelerated aging increased across ascending tertiles of these indicators. Mediation analysis further demonstrated that vitamin E intake exerted significant mediating effects on the associations between TyG and its related parameters and PhenoAgeAccel (P < 0.05). Among all indices assessed for their diagnostic performance in detecting accelerated aging, TyG-WHtR demonstrated the highest diagnostic accuracy (area under the curve [AUC] = 0.694, 95% CI: 0.673, 0.715). In conclusion, TyG and its obesity-related metrics were positively associated with accelerated phenotypic aging. Vitamin E intake mediated the associations between these parameters and PhenoAgeAccel.