Changes in Serum Insulin-Like Growth Factors,Not Leptin,Are Associated With Postnatal Weight Gain in Preterm Neonates

Abstract

Background: Serum concentrations of conventional nutrition-related proteins, such as albumin, prealbumin, transferrin, and retinol-binding protein, are usually inconsistent with changes in anthropometric measurements in the postnatal period. The aim of this study was to evaluate how reliable growth hormone (GH), insulin-like growth factors (IGFs), IGF-binding proteins (IGFBPs), and leptin, the proteins known to be involved in the regulation of growth, are in reflecting postnatal growth and nutritional status in preterm neonates. Methods: Blood samples and anthropometric measurements were collected from 55 preterm neonates (chronological age 30.4 ± 2.8 weeks) for 4 continuous weeks (weeks 0 to 3). Results: After adjusting for chronological age, body weights and serum IGF-II concentrations were significantly greater and serum transferrin concentrations were significantly lower in weeks 2 and 3 than in week 0 (repeated-measures analysis of variance (ANOVA) and Bonferroni test, p < .05). Forward stepwise multivariate regression analysis showed that change in total IGF-I (week 0 to week 3) was a positive predictor, and changes in insulin and prealbumin were negative predictors of postnatal weight gain. In addition, daily fat intake was a positive predictor of postnatal length increases, and changes in prealbumin, insulin, and GH were negative predictors of postnatal changes in the ponderal index (weight × length^–3). Changes in GH and IGFBP-2 were negative predictors of changes in head circumference and triceps skinfold thickness, respectively. Conclusions: Serial measurements of serum IGF-I and IGF-II may be useful adjuncts to anthropometric measurements for monitoring postnatal growth and nutritional status in preterm neonates.

Clinical observations indicate that serum concentrations of conventional nutrition-related proteins are inconsistent with the growth response in preterm neonates. In this study, we demonstrate that increases in serum concentrations of insulin-like growth factors significantly contribute to weight gain in early postnatal life in preterm neonates.

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