Leptin, triglycerides, and interleukin 6 are independently associated with C-reactive protein in Japanese type 2 diabetic patients

The aim of the present study was to investigate the factors contributing to the concentration of serum C-reactive protein in type 2 diabetic patients. One hundred and 48 Japanese type 2 diabetic patients were studied. In conjunction with C-reactive protein (CRP), BMI, systolic and diastolic blood pressure, glycosylated hemoglobin (HbA1c), fasting concentrations of plasma glucose, and serum lipids (triglycerides, HDL cholesterol, and total cholesterol), interleukin 6 (IL-6), and leptin were measured. Insulin resistance was also estimated by the insulin resistance index of homeostasis model assessment (HOMA-IR). With univariate analysis, serum CRP was positively correlated with BMI (r = 0.281, P < 0.001), diastolic blood pressure (r = 0.176, P = 0.048), triglycerides (r = 0.293, P < 0.001), HOMA-IR (r = 0.294, P < 0.001), IL-6 (r = 0.323, P < 0.001), and leptin (r = 0.330, P < 0.001), and negatively correlated with HDL cholesterol (r = −0.181, P = 0.028). Multiple regression analyses showed that serum CRP was independently predicted by the level of IL-6 (P < 0.001, F = 4.04), leptin (P < 0.001, F = 7.09), and triglycerides (P < 0.001, F = 15.13), which explained 17.6% of the variability of serum CRP concentration in these patients. From these results, it can be concluded that along with IL-6 and triglycerides, leptin is another important independent factor that is associated with CRP in Japanese type 2 diabetic patients.