Plasma concentration of Retinol Binding Protein 4 (RBP4) in relation to nutritional status and kidney function in older population of PolSenior Study

Purpose: The aim of the study was to assess plasma RBP4 concentration in elderly subjects in relation to nutritional status and kidney function in the population of the PolSenior Study. Material and methods: We assessed RBP4, glucose, insulin, albumin, lipid profile, C-reactive protein, (hsCRP) and creatinine concentrations in 2614 PolSenior Study participants (1235 women and 1379 men). The study group was divided based on BMI and HOMA-IR values, and the occurrence of diabetes. Results: Plasma RBP4 concentration was similar in normal weight, overweight, and obese subgroups, both in women (40.4 vs 40.8 vs 41.8 ng/ml, respectively), and men (41.2 vs 40.3 vs 42.9 ng/ml, respectively). Similar values were found in subjects with HOMA-IR < 2.5; >= 2.5 and diabetes, while those with decreased eGFR ( < 60 ml/min/1.73 m(2)) were characterized by increased RBP4 levels [46.0 (32.0-64.8) vs 39.4 (28.2-54.9) ng/ml; p < 0.001]. Plasma RBP4 level variability was explained by: age, waist circumference or BMI, and eGFR, but not HOMA-IR and/or hsCRP. The standardized coefficients beta (slopes) for BMI and waist circumference were similar. Conclusions: The results revealed that in older subjects, circulating RBP4 levels are mostly affected by kidney function and modestly by age, gender, and nutritional status, but not insulin resistance.