Elevated levels of interleukin-18 are associated with several indices of general and visceral adiposity and insulin resistance in women with polycystic ovary syndrome

OBJECTIVE: Our aim was to analyze levels of proinflammatory biomarker interleukin-18 (IL-18) in healthy controls and patients with polycystic ovary syndrome (PCOS) focusing on its association with obesity, clinical, hormonal, and metabolic characteristics. SUBJECTS AND METHODS: Fifty-eight patients with PCOS were enrolled in the study fulfilling the Rotterdam criteria and were matched for age, body mass index (BMI), and ethnicity with 30 healthy controls. Detailed anthropometric measurements, clinical investigations, hormonal and biochemical tests were obtained between the 3(rd) and 5(th) day of a menstrual cycle. A subanalysis of the PCOS group was performed separating patients into several groups according to a waist-to-height ratio (WHtR), insulin resistance (IR), and free androgen index (FAI). Serum IL-18 levels were measured using the ELISA method. RESULTS: Levels of IL-18 were similar between PCOS patients and controls. IL-18 was higher in overweight/obese women compared to normal-weight women when analyzing all participants together and separately PCOS or controls group (p < 0.001, p < 0.001, p = 0.01, respectively). Additionally, IL-18 levels were higher in high-WHtR and IR subgroups compared to low-WHtR (p < 0.001) and non-IR PCOS women (p < 0.001). PCOS women with high FAI had greater serum IL-18 levels than normal-FAI patients (p = 0.002). Levels of IL-18 correlated positively with most of the anthropometric and metabolic parameters. In multiple linear regression, age, waist circumference, and fasting insulin were independently related factors with IL-18. CONCLUSION: Elevated levels of IL-18 were related to several indices of general and visceral adiposity and insulin resistance in PCOS.