Association of retinol-binding protein 4 with metabolic syndrome in first-degree relatives of type 2 diabetic patients

Background: Retinol‑binding protein 4 (RBP4) is known to regulate lipid and glucose metabolism and insulin resistance. The influences of RBP4 on metabolic syndrome (MS) are still unclear. The purpose of this study is to evaluate the association between serum levels of RBP4 and MS components in first‑degree relations of type 2 diabetic patients. Materials and Methods: This cross‑sectional study was performed within the framework of the diabetes prevention project in Isfahan. This study has been conducted during 2012–2013. Seventy‑eight subjects participate, with an average age of 43.20 ± 5.29 years. Weight, height, waist and hip circumferences, blood pressure (BP) of participants, fasting plasma glucose, hemoglobin A1c, total cholesterol, high‑density lipoprotein cholesterol, triglyceride (TG), and serum RBP4 were measured from fasting blood sample taken from each participant after an overnight fast (12–14 h). Results: Systolic and diastolic BP were significantly higher in people in top median of RBP4 (11.8 ± 1.5 vs. 11.0 ± 1.2, P = 0.01 and 7.8 ± 1.0 vs. 7.3 ± 0.9, P = 0.03). Moreover, TG in people with high levels of RBP4 was higher compared with those with low levels of RBP4 (177.7 ± 97.6 vs. 138.7 ± 56.9, P = 0.02). People with low levels of RBP4 had significant greater hip circumferences (107.9 ± 7.5 vs. 104.3 ± 8.0, P = 0.04). There was no correlation between RBP4 and MS in crude model (odds ratio [OR]: 1.00, 0.95–1.05, P = 0.97). This null correlation remained after adjustment for body mass index, age, and physical activity (OR: 0.93, 0.91–1.07, P = 0.31). Conclusion: Although RBP4 levels were positively association with some risk factors of MS including hip circumference, TG, and systolic and diastolic BP, it does not seem to be a valuable marker for identification of the MS in the first relative degree of diabetic patients.