Low Serum Concentrations of Insulin-like Growth Factor-I in Children with Active Crohn Disease: Effect of Enteral Nutritional Support and Glutamine Supplementation

Abstract

Background: Impaired growth is a frequent problem in childhood Crohn disease. Low serum concentrations of insulin-like growth factor-I (IGF-I), an important marker of nutritional status and linear growth, have been described in children with Crohn disease. This study tested the hypotheses that enteral nutritional support and glutamine supplementation would be associated with improvements in serum IGF-I levels in children with Crohn disease. Methods: In a double-blind randomized controlled study, 15 children with active Crohn disease (8 boys, 7 girls; mean age 11.3 years, range 6.8-15.7) were assigned to receive a 4-week course of either a standard low glutamine polymeric diet (4% of amino acid content) (Group S, n = 8) or an isocaloric, isonitrogenous, glutamine-enriched polymeric diet (42% of amino acid content) (Group G, n = 7). Serum IGF-I was measured by a radioimmunoassay method at 0 and 4 weeks and converted to standard deviation scores (SDS). Weight SDS, height SDS, weight-for-height, height-for-age, mid-arm circumference (MAC), serum albumin, platelet count, orosomucoid and the paediatric Crohn disease activity index (PCDAI) were also measured at 0 and 4 weeks. Results: IGF-I SDS were significantly depressed in all the children at the start of the study (below-2 SDS) and remained so after 4 weeks of enteral nutritional support. Within each group, there was no significant change in IGF-I SDS ( P = 0.306 for Group S and P = 0.903 for Group G). Nor was there any significant difference between the two groups when changes in IGF-I SDS over the 4-week period were compared ( P = 0.568), although the proportion of patients experiencing an increase in IGF-I levels was greater in Group S (7 of 8 (87%) versus 2 of 7 (28%); P = 0.040). Weight SDS ( P = 0.002), weight-for-height ( P = 0.001) and mid-arm circumference ( P = 0.001) increased significantly in Group S but the increases in Group G were not statistically significant. No significant correlation was found between changes in IGF-I SDS and changes in the following parameters: weight SDS ( r = 0.170; P = 0.545), height SDS ( r = -0.240; P = 0.389), weight-for-height ( r = 0.261; P = 0.348), PCDAI ( r = -0.156; P = 0.579) or orosomucoid ( r = 0.173; P = 0.537). There was a significant negative correlation between changes in PCDAI and changes in weight SDS ( r = -0.79; P < 0.001), and serum albumin ( r = -0.76; P = 0.001) and a positive correlation between changes in PCDAI and changes in platelet count ( r = 0.69; P = 0.004). Conclusions: Serum IGF-I SD scores were greatly diminished in children with active Crohn disease and showed no significant improvements after 4 weeks of nutritional support. Glutamine supplementation was not associated with any significant alterations in serum IGF-I.