Impact of cortisol on liver fat and metabolic health in adrenal incidentalomas and Cushing's syndrome.

OBJECTIVE

To evaluate liver fat content in patients with non-functional adrenal incidentalomas (NFAI), mild autonomous cortisol secretion (MACS), and Cushing's syndrome (CS), and assess its relationship with cortisol levels.

METHODS

This cross-sectional study used retrospective data from 103 NFAI patients, 100 MACS (serum cortisol after a 1-mg dexamethasone test >50 nmol/L), and 59 with CS. Abdominal CT scans measured hepatic and splenic CT values to calculate the liver-to-spleen (L/S) ratio. Metabolic indicators including fasting plasma glucose (FPG), LDL-c, HDL-c, HbA1c, etc were measured. Mediation analysis was used to explore the indirect effects of metabolic traits on the cortisol-liver fat relationship.

RESULTS

Patients included 103 NFAI, 100 MACS, and 59 CS. MACS patients had higher NAFLD prevalence (57%) than NFAI (26.2%, p < 0.001) but lower than CS (66.1%, p < 0.001). MACS and CS were associated with NAFLD (OR 3.83 and OR 5.73, p < 0.01), adjusted for age, body mass index (BMI), and covariates. Midnight serum cortisol correlated with L/S ratio (p < 0.001). HbA1c and Triglyceride-glucose index (TyG) mediated 24.5% and 49.5% of the cortisol and L/S ratio association, respectively. FPG, HbA1c, HDL-c, and TyG mediated the association between MACS or CS and the L/S ratio. Homeostasis model assessment of insulin resistance (HOMA-IR), fructosamine, and triglycerides mediated for MACS, while alkaline phosphatase did so for CS. Total cholesterol, LDL-c, ALT, AST, γ-GT, insulin, and uric acid did not mediate the association.

CONCLUSION

MACS and CS are linked to significant metabolic disturbances, including increased liver fat and impaired glucose and lipid metabolism, contributing to fatty liver.