Fig. 2

Association between NHHR and the progression of prediabetes in restricted cubic spline analysis: Crude model, unadjusted crude representation (A); Model 1, adjusted for sociodemographic variables such as age, gender, educational level, location, and marital status (B); and Model 2, further adjusted for confounding factors including smoking status, drinking status, HbA1c and hypertension, cardiovascular disease and statin use (C)