Beyond BMI: insulin resistance emerges as the key metabolic correlate of AMH in PCOS.

Background: The association between anti-Müllerian hormone (AMH) levels, body weight and insulin resistance in women with polycystic ovary syndrome (PCOS) has been extensively discussed, yet evidence remains conflicting. Therefore, the aim of this study was to determine the relationship between AMH levels and metabolic parameters among reproductive-age women with PCOS in Poland. Methods: This retrospective study included 156 women diagnosed with PCOS according to the Rotterdam criteria and 156 controls without PCOS. Serum AMH, fasting glucose, and fasting insulin concentrations were measured, and insulin resistance was assessed using the homeostasis model assessment (HOMA-IR). Multiple regression, interaction, and mediation analyses were performed to evaluate the relationships between BMI, insulin resistance, and AMH levels. Results: A negative association between AMH concentration and both fasting insulin and HOMA-IR was revealed. Subsequent analysis further demonstrated that the relationship between HOMA-IR and AMH is independent of BMI, whereas the association between BMI and AMH was weaker and likely mediated by insulin resistance. Conclusions: Insulin resistance appears to represent a stronger metabolic correlate of AMH levels than BMI in women with PCOS. These findings may suggest that metabolic dysfunction, rather than excess body weight alone, is more closely associated with AMH alterations in PCOS.