Compared with the polyp-free group with normal glucose tolerance, FPG, 2hPG, HOMA-IR, plasma visfatin, and resistin levels were significantly higher in the polyp-free group with prediabetes (P = 0.025 for FPG; P = 0.009 for 2hPG; P = 0.034 for HOMA-IR; P = 0.001 for visfatin; P = 0.041 for resistin, respectively); plasma adiponectin levels were significantly lower [(9.2 ± 4.4 vs 13.3 ± 3.9) mg/L, P = 0.028]; and the other clinical parameters were not statistically significant between the two groups (P > 0.05) (Table 1, Fig. 2). Here, RETN is linked to prediabetes syndrome.