BOP% was positively correlated with PI (rs = 0.60 and rs = 0.79, for the PCOS group and the control group, respectively, p < 0.001), BMI in the control group (rs = 0.40, p = 0.0368), fasting insulin (rs = 0.36, p = 0.0469), HOMA-IR in the study group (rs = 0.48, p = 0.0068), and negatively correlated with salivary testosterone levels in the PCOS group (rs = − 0.37, p = 0.0424). Here, INS is linked to polycystic ovary syndrome.