Insulin resistance–related indices have been increasingly evaluated for their association with cognitive outcomes in type 2 diabetes (T2D). In this prospective cohort study of 1,412 individuals with T2D, investigators assessed whether the triglyceride glucose–body roundness index (TyG-BRI) was longitudinally associated with cognitive performance and whether arterial stiffness mediated this relationship. The study was published in the Journal of Diabetes and Its Complications.

TyG-BRI was calculated by multiplying TyG [Ln (fasting triglyceride - fasting plasma glucose / 2)] and body roundness index (BRI). Arterial stiffness was measured using pulse wave velocity (PWV) by tonometry. Cognitive function was assessed using the Repeatable Battery for Assessment of Neuropsychological Status (RBANS).

At baseline, adjusted analyses demonstrated an inverse association between Ln TyG-BRI and total RBANS score (coefficient −1.33; 95% CI −2.62 to −0.40). Among 823 patients with follow-up cognitive assessment over up to 8.4 years, the inverse association persisted in adjusted linear mixed models (coefficient −2.01; 95% CI −3.60 to −0.41). Higher Ln TyG-BRI was associated with reductions in delayed memory, visuo-spatial/construction, and attention domains during follow-up. Mediation analysis showed that PWV accounted for 16.8% of the association between Ln TyG-BRI and total RBANS score.

Higher TyG-BRI was longitudinally associated with lower cognitive performance across global and specific domains in T2D. Arterial stiffness partially mediated this relationship, suggesting a potential mechanistic pathway.