Effects of size at birth, gestational age and early growth in preterm infants on glucose and insulin concentrations at 9-12 years

Aims/hypothesis. To test the hypothesis that small size for gestation and poor postnatal growth in preterm infants is associated with higher fasting and post-load plasma glucose and insulin concentrations at 9-12 years of age. Methods. Prospective follow-up at 9-12 years of 385 preterm children with birth weight less than 1850 g, who had anthropometry recorded at birth, 18 months and 7 years. Fasting plasma glucose, insulin, proinsulin and 32,33 split proinsulin concentrations and glucose and insulin concentrations 30 min after a standard glucose load were measured. Results. Post-load glucose concentrations were negatively related to birth weight, independently of gestation or subsequent growth. Fasting split proinsulin and 30-min insulin concentrations were highest in children who showed the greatest increase in weight centile between birth and current follow-up, regardless of gestation. When weight during childhood was included, birthweight centile was, however, no longer statistically significant: concentrations of fasting, split, proinsulin and 30-min insulin were highest in those children who had shown the greatest increase in weight centile between 18 months of age and current follow-up, with no evidence of a greater effect in those who were smallest at 18 months. Conclusion/interpretation. Our findings suggest that fetal growth influences plasma glucose 30 min after a. glucose load in preterm children at 9-12 years. In contrast, childhood weight gain is the most important factor influencing insulin concentrations and this effect is the same regardless of early size.