Fig. 2

The relationship between SUA and BMD. Adjusted smoothed curves corresponding to the relationship between SUA levels and BMD. A generalized additive model revealed a thresholded non-linear relationship between SUA and BMD in OP patients with a BMI < 24 kg/m2. Red, green, and blue curves respectively correspond to estimated values for OP patients with a BMI < 24 kg/m2, 24–28 kg/m2, and > 28 kg/m2. Models were adjusted for age, gender, 25(OH)D levels, and BUN. The red curve in Model 3 exhibited an inflection point (K) at 2.96 per 100 μmol/L. SUA, serum uric acid; BMD, bone mineral density; BMI, body mass index; 25(OH)D, 25-hydroxy vitamin D; BUN, blood urea nitrogen