Serum Glycocholic Acid-to-Total Bile Acid Ratio Is Independently Associated with Nonalcoholic Fatty Liver Disease: A Retrospective Cross-Sectional Study

Introduction and Aims. Bile acids play an essential role in the progression of nonalcoholic fatty liver disease (NAFLD). This study was aimed at investigating the association of the serum glycocholic acid- (GCA-) to-total bile acid (TBA) ratio with NAFLD in the general population. Materials and Methods. A total of 6708 subjects (2859 cases with NAFLD and 3849 controls) were enrolled in the development cohort and additional 1568 subjects (784 cases with NAFLD and 784 controls) in an independent validation cohort. Demographic characteristics and biochemical data were compared between subjects with NAFLD and controls. Multivariate logistic regression analysis was performed to determine the association of the GCA-to-TBA ratio with NAFLD. A novel model incorporating the GCA-to-TBA ratio was developed for screening NAFLD from the general population. Results. The serum TBA and GCA levels were significantly higher in subjects with NAFLD than in those without NAFLD (2.8 (2.0-4.2) μmol/L vs. 2.5 (1.8-3.7) μmol/L and 1.30 (1.10-1.53) μg/mL vs. 1.28 (1.08-1.50) μg/mL, respectively, all p ≤ 0.01 ), whereas the serum GCA-to-TBA ratio was significantly lower in subjects with NAFLD than in subjects without NAFLD (0.44 (0.33-0.60) vs. 0.48 (0.36-0.64), p ≤ 0.01 ). Logistic regression analysis showed that the GCA-to-TBA ratio was independently associated with NAFLD after adjustment for confounding factors (odds ratio: 0.81, 95% confidence interval (CI): 0.71-0.92, p ≤ 0.01 ). The area under the receiver operating characteristic curve of the novel developed GCA-to-TBA ratio score model in discriminating NAFLD was 0.84 (95% CI: 0.83-0.85) in the development cohort and was 0.91 (95% CI: 0.36-0.65) in the validation cohort. Conclusion. The serum GCA-to-TBA ratio is independently associated with NAFLD. A simple novel model incorporating the GCA-to-TBA ratio score has a good performance in discriminating NAFLD from the general population.