Association between triglyceride glucose index and abnormal liver function in both urban and rural Chinese adult populations: Findings from two independent surveys

The purpose of this study was to investigate the association between triglyceride glucose (TyG) index and abnormal liver function both in urban and rural Chinese adult populations. The 5824 urban (Nanjing) and 20,269 rural (Hefei) Chinese adults, from random selected households provided clinical history, glucose, lipids, anthropometric, and blood pressure measurements. Liver functions were assessed using Alanine Aminotransferase (ALT). Linear regression was applied to examine the dose-response relationship between TyG index and ALT. Logistic regression was used to estimate the association between TyG index and abnormal liver and function. Cubic spline models were applied to investigate the dose-response association between TyG index and abnormal liver function. C-statistics was used to compare the discriminable capacity over triglyceride, glucose and TyG index. Linear dose-response relationship was identified between TyG index and ALT as 1.222 IU increase by 1 unit increase of TyG index (1.242 for urban population and 1.210 for rural population). The 6.0% of urban and 11.0% of rural Chinese adults were observed to have abnormal liver function. The linear association between TyG index and abnormal liver function was revealed as 2.044 (1.930 to 2.165) of odds ratio by in unit increase of TyG index (2.334 for urban population and 1.990 for rural population). Higher C-statistics was found for TyG index compared with fasting glucose and triglyceride both in Chinese urban and rural populations. This study suggested in both urban and rural Chinese adult populations, TyG index is associated with abnormal liver function. TyG index is a potential indicator to identify high-risk individuals with metabolic disorders, for example impaired liver function in Chinese population, especially in Chinese urban population.