Serum Osteoprotegerin is Diminished in the Polycystic Ovary Syndrome and Associated with Insulin Resistance

Abstract

Abstract Introduction: The polycystic ovary syndrome (PCOS) is a common endocrine disorder of reproductive age characterized by androgen excess and anovulation. PCOS is associated with insulin resistance (IR) and cardiovascular risk factors. Osteoprotegerin (OPG), an osteoclastogenesis inhibitor, has recently been related to metabolic and vascular disorders suggesting a possible link between OPG, PCOS and IR. Objectives: To determine the association between OPG and IR in women suffering from PCOS and to review the existing literature. Materials and Methods: Informed, written consent was obtained from 30 premenopausal women classified as PCOS (n = 13) or controls (n = 17) according to the Rotterdam criteria. Obese patients were excluded from the study. Biochemical analyses were performed including hormonal parameters, basal and after glucose overload determination of glucose and insulin. Serum OPG (pmol/L) was performed using a commercial enzyme immunoassay. Results: PCOS patients showed higher fasting glucose and a tendency towards higher glucose concentration in the rest of the curve. Serum OPG concentration was significantly lower in PCOS patients than in controls (PCOS 1512.6 ± 95.7 vs Controls, 1952.5 ± 154.8 pg/mL, p = 0.023). Among PCOS women, those suffering from IR showed significantly diminished OPG levels (n = 9; 1365.3 ± 88 pg/mL; p = 0.023), compared to non-insulino-resistant PCOS (n = 4; 1844.0 ± 140.2 pg/mL; p = 0.03). Conclusion: OPG concentration is diminished in PCOS independently of obesity. Further decrease is observed in those suffering from IR. All these findings suggest that OPG may not be implicated in the increased cardiovascular risk observed in PCOS.