Association between serum adipsin levels and insulin resistance in subjects with various degrees of glucose intolerance

Abstract

Context: The association between adipsin and glucose metabolism in human subjects remains unclear. Objective: We investigated the associations between adipsin and insulin resistance/b-cell function in subjects with various degrees of glucose intolerance. Design: Fasting blood samples were collected for measurements of fasting plasma glucose (FPG), insulin, and adipsin. An oral glucose tolerance test was conducted in subjects with no history of diabetes. Setting: This study was conducted at a medical center. Patients: We enrolled 240 subjects with no history of diabetes and 80 patients with known type 2 diabetes (T2D) on diet control or metformin monotherapy. Main Outcome Measure: B-cell function and insulin resistance were assessed using the homeostasis model assessment (HOMA-b and HOMA-IR, respectively). Results: Levels of serum adipsin were higher in subjects with normal glucose tolerance (4.0 ± 1.1 mg/mL) or prediabetes (4.0 6 1.5 μg/mL) compared with subjects with newly diagnosed diabetes (3.8 ± 1.1 μg/mL) or with known T2D on diet control (3.4 6 1.0 μg/mL) or metformin monotherapy (3.0 ± 1.0 μg/mL, P , 0.001). There was no significant association between adipsin and HOMA-β. In contrast, there was an independent negative association between adipsin and HOMA-IR (β coefficient 20.414, 95% CI 20.720 to 20.109, P = 0.008). The association was more prominent in subjects with a body mass index (BMI) ≥25 kg/m2 or an FPG ≥100 mg/dL (P interaction , 0.001 and 0.014, respectively). Conclusions: Serum adipsin levels were negatively associated with insulin resistance, especially in subjects with a BMI ≥25 kg/m2 or an FPG ≥100 mg/dL.