Association between triglyceride–glucose index and all-cause and cardiovascular mortality in US adults: A cohort study

The aim of this study was to investigate the association between the triglyceride-glucose (TyG) index and all-cause mortality and cardiovascular mortality, and to assess age differences. We analyzed data from the National Health and Nutrition Examination Survey (1999-2018), which included 101,316 participants. Restricted cubic spline and Cox regression models were used to examine the relationship between the TyG index and mortality rates in a sample of adult patients in the United States, age analysis was performed. Subgroup analysis was performed to evaluate potential differences in the relationship between the TyG index and mortality rates in different subgroups. The final analysis included 21,959 individuals. Observed were 3269 all-cause mortalities and 846 cardiovascular mortalities. Elevated TyG index values were associated with a significant rise in mortality, as depicted by Kaplan-Meier curves for both all-cause and cardiovascular causes (all-cause mortality: P < .001; cardiovascular mortality: P < .001). Analysis using restricted cubic splines uncovered a nonlinear association between baseline TyG index and both all-cause and cardiovascular mortality rates, with highly significant statistical correlations (all-cause mortality: P < .001; cardiovascular mortality: P = .004), with thresholds of 9.47 and 9.427. Participants were further categorized by age and divided into quartiles for survival curve analysis. Within the ≥ 40 < 60 age group, survival analyses revealed pronounced differences in mortality rates across quartiles (all-cause: P < .001; cardiovascular: P < .001). This study found a significant positive correlation between the TyG index and the overall mortality rate as well as the cardiovascular disease mortality rate among adults in the United States aged ≥ 40 and < 60.