Higher serum retinol-binding protein concentration in Indonesian neonates in Surabaya than Japanese neonates in Kobe

The concentrations of serum retinol-binding protein (RBP), prealbumin (PA) and vitamin A of Indonesian neonates were compared with those of Japanese neonates. The mean serum concentrations of both PA and vitamin A did not differ significantly in Indonesian and Japanese neonates. Indonesian neonates had significantly higher serum RBP (2.75 + 0.87 mg/dl, mean + SD) than Japanese neonates (1.65 + 0.55 mg/dl, p < 0.01). The molar ratio of vitamin A:RBP in Indonesian infants was significantly lower than in Japanese infants (p < 0.02), and this in turn is indicative of increased concentrations of retinol-free RBP in the plasma of Indonesian neonates. The results suggest that RBP metabolism in Indonesian neonates differs from that in Japanese neonates.