Relationship between Serum Liver Transaminase and Metabolic Syndrome in the Aged Based on Restrictive Cubic Spline Model

Background Metabolic syndrome (MS) has become a global health problem, and most studies have focused on the correlation of MS and its components with alanine aminotransferase (ALT) and aspartate aminotransferase (AST), but whether there is a dose-response relationship of ALT and AST with MS needs to be further explored. Objective To explore the relationship of ALT and AST with the risk of MS in the elderly, and provide a reference basis for the prevention and control of MS. Methods A health examination with multi-stage sampling method was conducted to residents (≥60 years) from 162 townships (streets) under jurisdiction of 18 cities of Henan Province in 2022. The investigation was performed with physical examination and laboratory test. Logistic regression model combined with restricted cubic spline model was recruited to analyze the relationship of ALT and AST with the risk of MS. Results Totally, 112 605 research participants were enrolled, of whome the prevalence of MS was 18.6% (20 935/112 605), ALT abnormality was 5.4% (6 132/112 605), and AST abnormality was 6.8% (7 661/112 605). The MS group showed a higher level of ALT and a lower level of AST than the non-MS group (P0.05), and a nonlinear dose-response relationship between AST and the risk of MS (P for overall