title: Gender differences in body composition deficits at diagnosis in children and adolescents with Crohn's disease.
abstract: BACKGROUND
  Childhood Crohn's disease (CD) is associated with poor growth and decreased body mass index (BMI); however, lean mass (LM) and fat mass (FM) deficits prior to therapy have not been characterized.
  
  
  OBJECTIVE
  To quantify LM and FM in incident pediatric CD subjects and controls, and to identify determinants of LM and FM deficits.
  
  
  METHODS
  Whole body LM and FM were assessed using DXA in 78 CD subjects and 669 healthy controls, ages 5-21 yr. Gender specific z-scores for LM (LM-Ht) and FM (FM-Ht) relative to height were derived using log linear regression models in the controls. Multivariate linear regression models adjusted for potential confounders.
  
  
  RESULTS
  CD was associated with significantly lower height and BMI for age. Within CD subjects, FM-Ht and LM-Ht were significantly lower in females compared with males (FM-Ht z: -0.66+/-0.83 vs. -0.08+/-0.95, p<0.01; LM-Ht z: -1.12+/-1.12 vs. -0.57+/-0.99, p<0.05). In females, CD was associated with significantly lower LM-Ht (p<0.001) and FM-Ht (p=0.001), adjusted for age, race and Tanner stage, compared with controls. LM and FM deficits were significantly greater in older females with CD; 47% of adolescent females had LM-Ht<or=5th percentile. In non-black males, CD was also associated with lower LM-Ht (p<0.02); FM-Ht deficits were not significant.
  
  
  CONCLUSIONS
  Incident CD was associated with significant LM deficits in males and females, and FM deficits in females. Future studies are needed to identify etiologies for the age and gender differences and to evaluate therapies for these deficits.
authors.affiliation: Children's Hospital of Philadelphia-Gastroenterology, Hepatology, and Nutrition, Philadelphia, Pennsylvania 19104, USA. thayu@email.chop.edu
authors.forename: Meena
authors.initials: M
authors.lastname: Thayu
authors.forename: Justine
authors.initials: J
authors.lastname: Shults
authors.forename: Jon M
authors.initials: JM
authors.lastname: Burnham
authors.forename: Babette S
authors.initials: BS
authors.lastname: Zemel
authors.forename: Robert N
authors.initials: RN
authors.lastname: Baldassano
authors.forename: Mary B
authors.initials: MB
authors.lastname: Leonard
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000886:Anthropometry; D001823:Body Composition; D015992:Body Mass Index; D002100:Cachexia; D002648:Child; D002675:Child, Preschool; D003424:Crohn Disease / Q000175:diagnosis* / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D012044:Regression Analysis; D012737:Sex Factors