title: Long-term development of bone geometry and muscle in pediatric inflammatory bowel disease.
abstract: OBJECTIVE
  The muscle-bone unit is crucial for normal bone development. As muscle mass is frequently reduced in pediatric patients with inflammatory bowel disease (pIBD), we investigated the impact of muscles on the bone development over time.
  
  
  METHODS
  Bone and muscle parameters were measured repeatedly in 102 pIBD patients (67 boys; 82 Crohn's disease; 30 newly diagnosed) by peripheral quantitative computed tomography (pQCT) at the forearm. The first and last measurements were included in the evaluation. Results were expressed as sex- and age-specific and partly height-corrected Z-scores for a healthy reference population.
  
  
  RESULTS
  At baseline, patients showed reduced Z-scores for height (median -0.7; range -3.7 to 1.6), trabecular bone mineral density (TrbBMD; -0.6; 3.0-2.8), and for height-corrected cortical cross-sectional area (CSA(height); -0.4; -3.0 to 2.2), cortical thickness (CrtTh(height); -0.7; -3.0 to 1.2), and MuscleCSA(height) (-1.0; -4.9 to 2.0; all P<0.01). Cortical bone mineral density (CrtBMD) and height-corrected TotalCSA(height) Z-scores were elevated (0.57; -4.55 to 2.8, both P<0.01). Over time, TotalCSA(height) (+0.36; -1.5 to 4.5) further increased, CorticalCSA(height) (+0.21; -2.1 to 3.0) and MuscleCSA(height) (+0.64; -2.0 to 3.9, all P<0.01) improved, whereas CrtBMD decreased toward normalization (-0.36; -5.1 to 3.6, P<0.05). The change in MuscleCSA(height) significantly correlated with the changes in TrbBMD (r=0.42), TotalCSA(height) (r=0.35), CorticalCSA(height) (r=0.38), and CrtTh(height) (r=0.24; all P<0.02). The relations became even stronger after adjustment for several confounders.
  
  
  CONCLUSIONS
  Bone metabolism and geometry are altered in pIBD patients expressed by low trabecular mineral density, low cortical thickness, and high cortical mineral density. The increased height-corrected cortical CSA might reflect a compensatory effect. In our cohort, treatment increased height-corrected muscle CSA and its changes were closely associated with bone parameters. Therefore, physical activity to enhance muscle mass and bone health should be promoted in pIBD patients.
authors.affiliation: Division of Pediatric Gastroenterology and Hepatology, Dr von Haunersches Kinderspital, Ludwig-Maximilians-University of Munich, Munich, Germany.
authors.forename: Katharina J
authors.initials: KJ
authors.lastname: Werkstetter
authors.forename: Susanne Bechtold-Dalla
authors.initials: SB
authors.lastname: Pozza
authors.forename: Birgit
authors.initials: B
authors.lastname: Filipiak-Pittroff
authors.forename: Stephanie B
authors.initials: SB
authors.lastname: Schatz
authors.forename: Christine
authors.initials: C
authors.lastname: Prell
authors.forename: Philip
authors.initials: P
authors.lastname: Bufler
authors.forename: Berthold
authors.initials: B
authors.lastname: Koletzko
authors.forename: Sibylle
authors.initials: S
authors.lastname: Koletzko
mesh_terms: D000293:Adolescent; D000886:Anthropometry; D015519:Bone Density; D001846:Bone Development; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D018737:Hand Strength; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed