BMI-C as a predictor of advanced liver fibrosis: mediation by insulin and synergy at F3+ in two NHANES cohorts (2017–23)

Abstract Introduction: Liver fibrosis is the advanced stage of metabolic dysfunction-associated steatotic liver disease (MASLD), affecting about 10% of adults with steatosis. BMI, the main anthropometric tool, does not distinguish fat mass from lean mass and does not capture central fat distribution. BMI-C (Body Morphometric Index – Corrected) is a proprietary index that corrects the dimensional error of BMI, identifies 23.7% of normal-BMI individuals at metabolic risk, and correlates fibrosis with insulin.

Objective

To validate BMI-C as a predictor of advanced liver fibrosis (F2+, F3+, F4) in two NHANES cohorts (2017–18 and 2021–23), and to investigate the role of insulin as a mediator and amplifier of the BMI-C effect on fibrosis.

Methods

Cross-sectional study with n = 5,014 adults (≥ 20 years) from NHANES 2017–18 and 2021–23 with valid liver elastography (FibroScan).