Development and Clinical Application of ApoC3 Protein as a Predictive Biomarker for Insulin Resistance in Polycystic Ovary Syndrome

I. Diagnostic Criteria The 2003 Rotterdam diagnostic criteria for PCOS jointly established by the European Society of Human Reproduction and Embryology (ESHRE) and the American Society for Reproductive Medicine (ASRM): Clinical and/or biochemical signs of hyperandrogenism; Oligo-ovulation or anovulation; Ultrasound findings: ovarian volume ≥ 10 mL, and/or \> 12 follicles with a diameter of 2-9 mm in a single section. A diagnosis of PCOS can be established when at least two of the following three criteria are met: ovarian dysfunction, hyperandrogenism, and polycystic ovarian morphology on ultrasound. II. Inclusion and Exclusion Criteria 1. PCOS with Insulin Resistance (PCOS-IR) Inclusion Criteria: Meets the 2003 Rotterdam diagnostic criteria for PCOS (at least 2 of the following 3 items): ① Oligo-ovulation or anovulation; ② Clinical or biochemical signs of hyperandrogenism; ③ Polycystic ovaries on ultrasound (unilateral or ovarian volume ≥ 10 mL). Insulin resistance (IR), meeting at least 1 of the following 3 criteria: ① HOMA-IR ≥ 2.5; ② Fasting insulin ≥ 15 μIU/mL; ③ Diagnosed impaired glucose tolerance (IGT) or type 2 diabetes mellitus (T2DM). Exclusion Criteria: Other endocrine disorders; Medication effects; Severe systemic diseases; Special physiological conditions (e.g., pregnancy, lactation); Poor sample quality. 2. PCOS without Insulin Resistance (PCOS-non-IR) Inclusion Criteria: Meets the PCOS diagnostic criteria (as above), with HOMA-IR \< 2.5 and no glucose metabolism abnormalities. Exclusion Criteria: Same as above.