Association Between Serum Adipsin Levels and Insulin Resistance in Subjects With Various Degrees of Glucose Intolerance

CONTEXT: The association between adipsin and glucose metabolism in human subjects remains unclear. OBJECTIVE: We investigated the associations between adipsin and insulin resistance/β-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: β-cell function and insulin resistance were assessed using the homeostasis model assessment (HOMA-β and HOMA-IR, respectively). RESULTS: Levels of serum adipsin were higher in subjects with normal glucose tolerance (4.0 ± 1.1 µg/mL) or prediabetes (4.0 ± 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 ± 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 −0.414, 95% CI −0.720 to −0.109, P = 0.008). The association was more prominent in subjects with a body mass index (BMI) ≥25 kg/m(2) 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/m(2) or an FPG ≥100 mg/dL.