Retinol-binding protein 4 in obese and obese-diabetic postmenopausal women in Montenegro
Introduction: Menopause is associated with an increase in visceral fat and obesity and is the leading risk factor for insulin resistance (IR) and type 2 diabetes mellitus (T2DM). Recent evidence suggests that retinol-binding protein 4 (RBP4) is not an independent determinant of IR and its role in human glucose metabolism is not well clarified. We examined RBP4 and its association with IR, cardiometabolic and kidney parameters in obese postmenopausal women with and without T2DM.
Methods: Basic anthropometric, biochemical parameters, and blood pressure (BP) were determined in 50 obese diabetic and 50 obese non-diabetic sedentary postmenopausal women, and compared with 50 healthy normal weight controls.
Results: Higher levels of RBP4 were observed in obese individuals, as compared with normal weight group (p=0.033). However, we did not find significant difference between obese non-diabetic and obese-diabetic individuals (p=0.583). Serum RBP4 did not correlate with anthropometric measurements or any indicator of glucose metabolism in diabetic group, whereas RBP4 correlated with creatinine (r=0.416, p=0.003), eGFR (r= -0.304, p=0.032) and triglycerides (r=0.484, p<0.001). In obese non-diabetic group, correlations were observed with fasting glucose (r=0.346, p=0.014), insulin (r=0.292, p=0.038), HOMA-IR (r=0.329 p=0.020), HbA1c (r=0.326, p=0.021), creatinine (r=0.399, p=0.004), eGFR (r= -0.389, p=0.005), HDL-c (r= -0.316, p=0.025), triglycerides (r=0.461, p<0.001), and systolic BP (r=0.286, p=0.044). In multiple regression analysis, triglycerides (Beta=0.302, p<0.001) and eGFR (Beta= -0.188, p=0.015) were independent predictors of RBP4.Conclusions: Serum RBP4 is not increased in obese type 2 diabetic postmenopausal women, but is associated with triglycerides and eGFR independently of diabetes.