The impact of early nutrition in premature infants on later childhood insulin sensitivity and growth

OBJECTIVES. Children born prematurely have decreased insulin sensitivity. The etiology of this insulin resistance is unknown. The aim of this study was to evaluate infant nutrition and its influence on insulin sensitivity and postnatal growth in children born <= 32 weeks' gestation. METHODS. A total of 56 healthy, developmentally normal, prepubertal children, aged 4 to 10 years were recruited. Thirty-seven were born <= 32 weeks' gestation, and 19 were control subjects born at term with a birth weight > 10th percentile. Insulin sensitivity (10(-4) min(-1) mu U/mL) was calculated from a 90-minute frequently sampled intravenous glucose tolerance test. Perinatal, nutritional, and growth data were obtained retrospectively from both neonatal and early infancy records in the premature cohort. RESULTS. Children born prematurely had decreased insulin sensitivity when compared with those born at term (13.8 vs 30.6). Neonatal nutrition was not correlated with insulin sensitivity; however, all of the infants had inadequate protein in the first month followed by excessive fat intake thereafter. Premature children with greater weight gain had lower insulin sensitivity. Higher carbohydrate intake in the first month of life was associated with greater weight gain from birth. No relationship was seen between weight gain and either protein or lipid intake. CONCLUSIONS. Prematurely born children are insulin resistant and have suboptimal neonatal nutrition. Greater childhood weight gain magnifies this reduction in insulin sensitivity and seems to be associated with early nutrition. We speculate that a high carbohydrate neonatal diet may lead to greater weight gain and a greater reduction in insulin sensitivity in this group.