IL-1 receptor antagonist levels are associated with glucose tolerance in polycystic ovary syndrome.

Abstract

To investigate serum interleukin-1 receptor antagonist (IL-1Ra) levels in women with polycystic ovary syndrome (PCOS). Serum IL-1Ra levels were measured at baseline in 73 women with PCOS and 45 control subjects (18-47 years), and in 27 women with PCOS who underwent oral and intravenous glucose tolerance tests (OGTTs and IVGTTs). IL-1Ra concentrations predicted OGTT 2-h glucose levels independently of BMI and insulin resistance (P ≤ 0·001) in women with PCOS. Serum IL-1Ra concentration was elevated in women with PCOS compared with controls [mean (SD): 309·5 (208·8) vs 199·1 (81·4) ng/l, P < 0·001], but the difference disappeared after adjusting for BMI. An increment of five BMI units raised IL-1Ra levels by 108·5 ng/l [95% confidence interval (CI): 85·5-131·5, r(2) = 0·603] in women with PCOS and only by 77·0 ng/l (95% CI: 50·5-103·5, r(2) = 0·512) in controls when adjusted for BMI and age. Levels of IL-1Ra in obese women with PCOS reflected decreasing OGTT-derived insulinogenic index (P = 0·032) and disposition index (P = 0·046) independently of BMI. Increased levels of IL-1Ra correlated with indices showing increasing insulin resistance and AUC insulin (P ≤ 0·002). Increased IL-1Ra levels in women with PCOS were largely explained by increasing adiposity. However, serum IL-1Ra concentrations predicted 2-h glucose levels independently of BMI suggesting that increased IL-1Ra may be associated with disturbed glucose metabolism.