Serum lipocalin-2 as an insulin resistance marker in patients with polycystic ovary syndrome

Background: Our aim was to investigate levels of lipocalin-2 and its relationship with metabolic factors in women with polycystic ovary syndrome (PCOS). Materials/Subjects and methods: In this cross-sectional study, two groups of women were studied: group 1 consisted of women with PCOS (no.=30), and group 2 consisted of control women with normal ovulatory function (no.=30). The circulating levels of free testosterone (T), DHEAS, glucose, insulin, triglycerides (TG), HDL, LDL and lipocalin were measured. Insulin resistance was assessed using the homeostasis model assessment (HOMA-IR). In order to determine a lipocalin value indicating insulin resistance, receiver operating characteristic (ROC) curves were established. Results: Serum lipocalin was significantly higher in PCOS subjects (54.26±15.58 vs 26.09±7.47 ng/ml, p=0.0001). We found a close correlation between lipocalin and insulin, lipocalin and HOMA-IR, lipocalin and T, and lipocalin and DHEAS. A cut-off level of >39.54 ng/ml for serum lipocalin has a predictive value for insulin resistance of 81% sensitivity and 82.1% specificity. Conclusion: In our study, lipocalin-2 levels were found to be significantly higher in women with PCOS compared to body mass index-matched controls. Serum lipocalin-2 may prove to be a useful marker for insulin resistance in patients with PCOS.