Plasma Retinol-Binding Protein-4 Concentrations Are Elevated in Human Subjects With Impaired Glucose Tolerance and Type 2 Diabetes

In their recent study, Cho et al. (1) demonstrated higher levels of retinol-binding protein-4 (RBP4) in in-dividuals with impaired glucose tolerance and type 2 diabetes. Additionally, higher waist circumferences increased with plasma RBP4 quartiles. This was also demonstrated by Graham et al. (2). Cho et al. suggested that visceral fat may be more important than total body fat in determining circulating RBP4 levels. In our study (3), we investigated whether visceral …