Metabolic Markers and Insulin Resistance

Blood samples were drawn via a venipuncture without any anticoagulant tubes for serum and EDTA—anticoagulant tubes for plasma. All blood samples were centrifuged at 1800 g for 10 min. After separation of serum and plasma samples, they were frozen at −80 °C until analysis. Glucose, lipid (TC and TG), and lipoprotein (HDL-C and LDL-C) levels were determined using the AU5800 auto analyzer (Beckman Coulter, Shizuoka, Japan). Insulin level was measured using the IMMULITE 2000 XPi analyzer (Siemens, Munich, Germany). To evaluate insulin resistance, the homeostasis model assessment of insulin resistance (HOMA-IR) was used. The formula used for calculating the index was as follows: fasting serum insulin (μU/mL) × fasting plasma glucose (mmol/L)/22.5 [28 (link)]. Fasting remnant lipoprotein cholesterol (RLP-C) was calculated using the formula TC˗(HDL-C + LDL-C) [29 (link)], and the atherogenic index of plasma (AIP) was calculated as log (TG/HDL-C) [30 (link)].