Unraveling the Association of Liver Steatosis and Fibrosis with Vitamin B12: A Cross-Sectional Study.

Background: There are conflicting studies reporting both an increase and a decrease in vitamin B12 (VB12) levels in non-alcoholic fatty liver disease (NAFLD). In this study, we aimed to dissect the effects of steatosis and fibrosis on VB12.

Methods: This is a cross-sectional study including all patients with a vibration-controlled transient elastography (VCTE) performed at the Hospital Miguel Servet (Zaragoza, Spain) between 2019 and 2022 for a chronic liver disease and having a recent blood test for VB12 levels. Liver fibrosis was assessed by VCTE and hepatic steatosis by ultrasonography and/or through controlled attenuation parameter (CAP).

Results: 1195 patients (NAFLD n = 441, other chronic liver disease n = 754) were included. Median age was 57 years, 53% female. Patients with NAFLD had lower levels of VB12 compared to the rest of chronic liver diseases (289 vs. 313 pg/mL, p < 0.001). A significant negative correlation was observed between VB12 levels and hepatic steatosis measured by CAP (r = -0.13, p < 0.001). A significant positive correlation was observed between VB12 levels and liver stiffness in patients with NAFLD in both sexes (men r = 0.31, p < 0.001 and women r = 0.15, p = 0.016). A significant association between VB12 levels and liver fibrosis in cirrhosis stage was observed in patients with NAFLD (OR 1.06, 95% CI, 1.025-1.098, p = 0.001).

Conclusion: VB12 levels were lower with greater hepatic steatosis. In NAFLD, VB12 levels were lower compared to other chronic liver diseases but their levels increased with higher liver stiffness and in cirrhosis stage.