Association between sedentary behavior, physical activity, and the triglyceride glucose index and its derived...

While sedentary behavior and physical activity have been associated with the TyG index, their associations with TyG-derived indices and their potential interaction remain unclear.

This study aimed to examine the independent and interactive associations of sedentary behavior and physical activity with the TyG index and its derived indices.

This cross-sectional analysis used NHANES 2013-2018 data. We employed survey-weighted multivariate regression and restricted cubic splines to evaluate independent and nonlinear associations. Multiplicative interaction terms were used to examine if physical activity levels altered the association between sedentary behavior and outcomes.

After multivariable adjustment, longer sedentary time was significantly associated with higher TyG index (β = 0.0051, p < 0.0001), TyG-BMI (β = 1.1395, p < 0.0001), TyG-WHtR (β = 0.0163, p < 0.0001) and TyG-WC (β = 3.0860, p < 0.0001). Higher physical activity showed inverse associations with TyG (β = -0.0039, p < 0.0001), TyG-BMI (β = -0.2677, p = 0.0007), TyG-WHtR (β = -0.0054, p < 0.0001) and TyG-WC (β = -1.0057, p < 0.0001). Nonlinear relationships were observed between physical activity and TyG-BMI, TyG-WHtR, and TyG-WC (p < 0.01). Significant interactions existed between sedentary behavior and physical activity on TyG (p = 0.037), TyG-WHtR (p = 0.047) and TyG-WC (p = 0.047).

Prolonged sedentary behavior and lower physical activity showed associations with adverse profiles of the TyG index and its derivatives. Significant interactions between these behaviors were observed, indicating a particularly important combined association with central obesity-related indices. Integrating reductions in sedentary time with increases in physical activity could represent a synergistic approach for improving metabolic health.