INS and metabolic syndrome: Results of the Sobel Test showed that the indirect association between adiponectin and MetS-IDF was significantly different from zero after controlling for insulin (z-test = 2.539, SE = 0.010, P = 0.011), BMI (z-test = 2.898, SE = 0.012, P = 0.004), waist circumference (z-test = 2.732, SE = 0.012, P = 0.006), HDL-cholesterol (z-test = 2.388, SE = 0.011, P = 0.017) or triglyceride concentration (z-test = 2.163, SE = 0.010, P = 0.031).