Fig. 2

Nonlinear associations of BFR and METS-IR with NAFLD risk. A Dose–response curve depicting the relationship between BFR and NAFLD risk. The solid line represents the odds ratio (OR), and the shaded area indicates the 95% confidence interval. The inflection point is identified at BFR = 25.103%; below this threshold, the risk increases sharply (OR = 1.61), while above it, the risk continues to rise but at a reduced slope (OR = 1.09). B Dose–response curve illustrating the association between METS-IR and NAFLD risk. The threshold is observed at METS-IR = 36.066; below this value, the risk escalates rapidly (OR = 1.72), whereas above it, the risk remains elevated but increases at a slower rate (OR = 1.47). C Restricted cubic spline curve demonstrating the association between BFR and NAFLD risk, using BFR = 32% as the reference point. The model incorporates knots at 17.9%, 28.3%, 36.1%, and 46.2% to capture the nonlinear association