The growth hormone insulin-like growth factor 1 axis in children and adolescents with inflammatory bowel disease and growth retardation

Context There is scarce knowledge about the growth hormone (GH) insulin-like growth factor-1 (IGF1) axis in children & adolescents with inflammatory bowel disease (IBD) and growth retardation. Objective To describe the pattern of GH and IGF1 secretion in children & adolescents with IBD. Design A retrospective review of 28 patients (23 M) of IBD (25 Crohn's Disease and three Ulcerative Colitis) and growth retardation who had investigation of the GH/IGF-1 axis. Height velocity (HV) and serum IGF1 were converted to standard deviation score (SDS); to account for delayed puberty in girls over 11 years and boys over 12 years, HV and serum IGF1 SDS were adjusted for bone age. Results Median (range) age and Ht SDS at the time of endocrine evaluation was 14·3 years (7·7,17·0) and -2·0(-3·6,-0·9), respectively. Median HVSDS over the prior 12 months was - 2·2(-7·7,2·8). Median peak serum GH on insulin tolerance test (ITT) was 5·8 mcg/l (1·3, 24·0), and median serum IGF1 SDS was -0·9(-3·1, 0·1). Five of 28 (18%) had a peak serum GH of > 12 mcg/l. Overall, four had biochemical evidence of functional GH deficiency (peak GH < 3 mcg/l and IGF1 SDS < 0) and 11 children had biochemical evidence suggesting GH resistance (peak GH > 6 mcg/l and IGF1 SDS < 0). However, only one child had a peak serum GH > 6 mcg/l and a very low IGF1 SDS of <-2·0. There was a negative association between peak serum GH and Ht SDS (r = -0·49, P = 0·008), but there was no association with HV and there was no association between IGF1 SDS and Ht or HV SDS. IGF1 SDS showed a negative association with erythrocyte sedimentation rate (r = -0·41, P = 0·04). Conclusion Growth retardation in children and adolescents with IBD is commonly associated with a range of biochemical abnormalities ranging from functional GH deficiency to GH resistance. In these children, poor relationship between systemic markers of growth and height velocity point to an important role of growth factors at the target organ level in modulating growth in children with IBD. The value of assessing the GH/IGF-1 axis and whether it predicts subsequent response to growth-promoting therapy requires further exploration.