Serum retinol-binding protein 4 levels in nonobese women with polycystic ovary syndrome

Objective To test whether there was a difference in serum retinol-binding protein 4 (RBP4) levels between subjects with polycystic ovary syndrome (PCOS) and those with a healthy regular menstrual cycle and, in addition, to correlate serum RBP4 levels with a variety of parameters. Design Clinical study. Setting University hospital. Patient(s) A total of 74 nonobese women were evaluated. Thirty-seven had PCOS, whereas the remaining 37 served as control subjects. Intervention(s) Serum RBP4 levels were analyzed using ELISA. Main Outcome Measure(s) Serum levels of FSH, LH, TSH, E 2 , T, insulin, glucose, cholesterol, triglycerides, and RBP4. Result(s) The women with PCOS had higher levels of serum RBP4, waist-to-hip ratio, LH, T, insulin, homeostatic model assessment of insulin resistance, cholesterol, and triglycerides. Logistic regression analyses revealed a significant association between odds ratio (OR) values of PCOS and both T (OR = 1.125; 95% confidence interval [CI] 1.050–1.205), and cholesterol levels (OR = 1.029; 95% CI 1.004–1.056). Age and triglycerides were significantly correlated to serum RBP4 levels by multiple linear regression analysis. Conclusion(s) Our study has shown that [1] elevated RBP4 levels might arise from triglyceride metabolism, and that RBP4 levels might not be influenced by PCOS itself. [2] RBP4 might not be a useful marker of insulin resistance in subjects with PCOS.