Recently, contrarily to previous studies [45, 46], Olszanecka-Glinianowicz et al. [48] reported significantly higher RBP4 levels in normal weight PCOS compared to obese PCOS subjects and significantly lower concentrations in normal weight controls compared to obese controls, with a negative correlation between RBP4 and HOMA-IR or insulin concentrations, hypothesizing a compensatory effect in the negative feedback between RBP4 and insulin resistance to prevent deterioration in obese PCOS patients. Here, RBP4 is linked to polycystic ovary syndrome.