title: A two-year longitudinal study of persistent lean tissue deficits in children with Crohn's disease.
abstract: OBJECTIVE
  Deficits in lean body mass have been reported in cross-sectional studies of children with Crohn's disease, but no longitudinal data exist from diagnosis. We observed the effects of Crohn's disease on body composition and bone mineral content (BMC), beginning at diagnosis and followed prospectively for 2 years.
  
  
  METHODS
  The study was conducted at 2 tertiary care centers for pediatric inflammatory bowel diseases. At diagnosis we recorded age, weight, height, levels of serum interleukin-6 and insulin-like growth factor-1, sexual maturation stage, disease activity, z scores for body mass index (BMI), fat-free mass (FFM), and bone mineral content (BMC). z Scores were adjusted for height and age, when appropriate. Measurements were made yearly in patients with Crohn's disease (n = 42) but only at the start of the study in controls (n = 81).
  
  
  RESULTS
  BMI and FFM z scores were significantly reduced at the time of diagnosis in children with Crohn's disease, compared with controls. During the 2-year study period, the BMI z scores normalized in patients with Crohn's disease, but the FFM z scores did not increase significantly. The BMC z scores increased significantly, but they were still lower than control values after 2 years. Changes in BMC during a period of 2 years were associated with increases in FFM (R(2) = 0.318, P < .01).
  
  
  CONCLUSIONS
  The correction of BMI that is associated with clinical improvement in children with Crohn's disease 2 years after diagnosis results from gains in fat mass. Significant FFM deficits might hamper normal acquisition of bone mass in children with Crohn's disease because of a lack of mechanical strain.
authors.affiliation: Connecticut Children's Medical Center, Hartford, Connecticut 06106, USA. fsylves@ccmckids.org
authors.forename: Francisco A
authors.initials: FA
authors.lastname: Sylvester
authors.forename: Scott
authors.initials: S
authors.lastname: Leopold
authors.forename: Miriam
authors.initials: M
authors.lastname: Lincoln
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Hyams
authors.forename: Anne M
authors.initials: AM
authors.lastname: Griffiths
authors.forename: Trudy
authors.initials: T
authors.lastname: Lerer
mesh_terms: D000293:Adolescent; D001823:Body Composition; D015992:Body Mass Index; D015519:Bone Density; D002648:Child; D003424:Crohn Disease / Q000150:complications*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D013851:Thinness / Q000209:etiology*