Objective: X-box binding protein-1 (XBP1) is a possible indicator of metabolic syndrome and diabetes. This study aimed to evaluate the relationship between serum XBP1 levels and polycystic ovary syndrome (PCOS).
Method: A prospective observational study was conducted with 88 patients. The first group was defined as the control group with ovulatory and normal-BMI patients (n = 28). The second group comprised of nonobese PCOS patients (n = 30). The third group included overweight/obese patients with PCOS (n = 30). Fasting plasma glucose, serum lipids, follicle stimulating hormone, luteinizing hormone, total testosterone, dehydroepiandrosterone and XBP1 levels l were evaluated in all groups.
Results: There was a significant difference in XBP1 levels between the study groups, and higher levels were observed both in the nonobese and obese PCOS groups than in the healthy controls (p < .001). The median level of XBP1 was 73.7 pg/ml in the control group, 114.11 pg/ml in the nonobese PCOS group, and 151.61 pg/ml in the overweight/obese PCOS group. A cutoff level of XBP1 at 95.79 pg/ml level was determined with a significant AUC (area under the curve) level of 99% and high specificity and sensitivity rates to predict PCOS. Also, a significant positive correlation was observed between XBP1 levels and BMI, waist circumference, fasting plasma glucose and triglyceride levels (p < .05).
Conclusions: XBP1 levels were significantly higher in PCOS patients, particularly in overweight/obese PCOS patients, than in the controls. Also, the parameters associated with metabolic syndrome were related to XBP1 levels.
Keywords: ER stress; Polycystic ovary syndrome; X-box protein 1; insulin resistance.