Most of the studies considered the following confounding variables: obesity (BMI > 30 kg/m2), hyperandrogenism, high blood pressure (BP), CVD, diabetes, hyperprolactinemia, congenital adrenal hyperplasia, thyroid disorder, Cushing ́s syndrome, hepatic or renal dysfunction, oral contraceptives, steroid hormones, and insulin-sensitizing medications. Here, INS is linked to diabetes mellitus.