Association of triglyceride-glucose index (TyG) and a body shape index (ABSI) with cognitive decline and dementia risk

Background : The triglyceride-glucose (TyG) index, used to assess insulin resistance (IR), and a body shape index (ABSI), a measure of visceral obesity, are both established risk factors for cognitive decline and dementia. However, longitudinal evidence for a causal link between ABSI and cognitive decline or dementia remains scarce, and the two indices have rarely been combined for predictive diseases. The study aimed to explore the associations between the TyG index, ABSI and the combined TyG-ABSI index with cognitive decline and the risk of dementia. Methods : This study included 370,744 participants from the UK Biobank who were free of dementia and had complete data at baseline. The TyG, ABSI and TyG-ABSI indices were categorized into quartiles. Logistic regressions were employed to assess the associations of TyG, ABSI and TyG-ABSI indices with cognitive decline; cox regressions were used to analyze the associations of these indices with the risk of all-cause dementia (ACD) and its subtypes. Restricted cubic splines (RCS) were used to explore the dose-response relationships of TyG, ABSI and TyG-ABSI indices with cognitive decline and the risk of dementia. Receiver operating characteristic curves (ROC) were used to evaluate their diagnostic value. Result: After adjusting for confounders, TyG, ABSI and TyG-ABSI indices were all significantly associated with cognitive decline. Additionally, compared with the lowest quartiles, the highest quartiles of TyG, ABSI and TyG-ABSI indices were associated with a significantly increased risk of ACD by 33% (HR=1.33, 95% CI: 1.13-1.57), 79% (HR=1.79, 95% CI: 1.65-1.94) and 67% (HR=1.67, 95% CI: 1.54-1.82), respectively. These indices were also significantly associated with the risk of Alzheimer's disease (AD) and vascular dementia (VD) (all P < 0.05). Finally, ABSI and TyG-ABSI demonstrated good ROC curve performance in predicting cognitive decline and dementia. Conclusion: There were significant associations among the TyG, ABSI and TyG-ABSI indices with the risk of cognitive decline and dementia incidence, respectively. Moreover, ABSI and TyG-ABSI index exhibited superior predictive performance compared with TyG alone and other TyG-derived indices (TyG-WC, TyG-BMI, TyG-WHtR).