Determinants of changes in linear growth and body composition in incident pediatric Crohn's disease.

BACKGROUND & AIMS: Pediatric Crohn's disease (CD) is associated with growth, lean mass (LM), and fat mass (FM) deficits. This study assessed and identified determinants of changes in height and body composition in children with CD following. METHODS: Whole-body LM and FM were assessed using dual-energy x-ray absorptiometry in 78 CD subjects at diagnosis, 6, 12, and a median of 43 months (range, 24-63) later. Race- and sex-specific Z scores for lean mass (LM-ht-Z) and fat mass (FM-ht-Z) relative to height were derived using reference data in >900 controls. Serum cytokines and growth factors were measured, and quasi-least squares regression was used to identify determinants of changes in height and body composition. RESULTS: LM-ht-Z and FM-ht-Z (both P<.005) improved significantly after diagnosis; however, female patients had persistent LM deficits vs controls (-0.50+/-1.02, P<.05). Serum interleukin-6, tumor necrosis factor-alpha, and lipopolysaccharide binding protein decreased significantly (all P<.001). Greater increases in LM-ht-Z were associated with infliximab therapy (P<.05), increases in albumin (P<.001) and decreases in erythrocyte sedimentation rate (P<.05), interleukin-6 (P<.005), and lipopolysaccharide binding protein (P<.05). Greater increases in FM-ht-Z were associated with glucocorticoid, methotrexate, and infliximab therapy, and increases in albumin (P<.05) and growth hormone binding protein (P<.05). Overall, height-Z did not improve; however, greater increases in insulin-like growth factor-1 (P<.05) and decreases in tumor necrosis factor-alpha (P<.05), interleukin-6 (P<.05), and lipopolysaccharide binding protein (P<.05) levels were associated with increases in height-Z. CONCLUSIONS: Immune-mediated mechanisms contribute to growth and body composition deficits in CD. Therapies should target these deficits.