Stratification of polycystic ovary syndrome by central adiposity phenotypes: Toward diagnostic precision

Polycystic ovary syndrome (PCOS) remains the most common endocrine disorder in reproductive-aged women, yet its diagnosis and classification are inconsistent. Conventional frameworks emphasize reproductive and androgenic features, while relying heavily on body mass index (BMI) as a proxy for adiposity. However, BMI fails to capture visceral fat distribution, which is a stronger determinant of insulin resistance, low-grade inflammation, and cardiovascular risk. Emerging evidence highlights waist-to-height ratio (WHtR) and waist circumference (WC) as superior markers of central adiposity and metabolic dysfunction in PCOS. Based on pooled data from recent studies, consolidated cut-offs for PCOS and insulin-resistant PCOS (PCOS-IR) were derived, allowing phenotype-based stratification according to adiposity patterns. These evidence-based thresholds distinguish the metabolic transition from general to insulin-resistant PCOS, providing practical reference points for clinical use. Based on these insights, we propose a hypothesis-based stratification of PCOS into three adiposity-driven phenotypes: lean PCOS with central adiposity, obese PCOS with predominant central adiposity, and obese PCOS with peripheral adiposity. This stratification framework integrates general and central adiposity measures to identify women at varying metabolic risk levels more accurately. Moving beyond BMI towards adiposity-driven classification is therefore a crucial step toward diagnostic precision in reproductive endocrinology.