Associations Between Anorexia Nervosa Severity, Liver Dysfunction, and Cobalamin Serum Concentration.

Background: Anorexia nervosa (AN) is a severe psychiatric disorder characterized by extreme malnutrition, leading to multiple organ dysfunctions, including liver impairment. While AST and ALT are standard markers for liver dysfunction, recent reports suggest that elevated cobalamin (vitamin B12) levels are frequently observed in AN patients. However, the association between cobalamin levels and liver dysfunction remains unclear. This study aims to investigate the relationship between cobalamin levels, liver enzyme abnormalities, and body mass index (BMI) in AN patients. Methods: This retrospective observational study included patients diagnosed with AN who visited the outpatient department or were hospitalized at Yokohama City University Medical Center between April 2012 and March 2021. Patients with alcohol use disorder, cancer, or vitamin supplementation were excluded. AST, ALT, and cobalamin levels were measured during routine blood tests, and BMI was calculated based on clinical records. Results: BMI was significantly negatively correlated with AST (r = -0.4703, p < 0.0001) and ALT (r = -0.3743, p < 0.0001). Patients with cobalamin levels >4000 pg/mL exhibited significantly lower BMI compared to those with lower cobalamin levels. Additionally, higher cobalamin levels were associated with increased AST and ALT levels. Conclusion: Elevated cobalamin levels, alongside AST and ALT, may serve as a possible supportive indicator of liver dysfunction and the severity of malnutrition in AN patients. Further research is needed to clarify the underlying mechanisms and clinical implications for nutritional assessment and liver dysfunction evaluation.