title: Seasonal variability of vitamin D and bone metabolism in infliximab-treated paediatric Crohn's disease.
abstract: BACKGROUND
  Paediatric Crohn's disease patients suffer from several complications, including low bone mineral density and inadequate serum levels of 25-hydroxy vitamin D.
  
  
  OBJECTIVE
  The aim of this prospective study was to address the effect of infliximab therapy on bone metabolism, bone mineral density and vitamin D homeostasis. The seasonal variability of serum vitamin D levels in relation to infliximab treatment was also analysed.
  
  
  METHODS
  Serum osteocalcin and beta-crosslaps (markers of bone metabolism), seasonal variability of vitamin D, and bone mineral density were assessed and followed throughout the yearlong treatment regimen of infliximab in 50 consecutive paediatric patients with moderate to severe Crohn's disease.
  
  
  RESULTS
  Bone forming osteocalcin levels were significantly (p<0.001) increased during infliximab therapy. In contrast, no significant changes in beta-crosslaps and vitamin D levels were observed. Vitamin D levels were significantly different when the summer and winter periods were compared at week 0 (p=0.039); however, this difference was not detected after one year of infliximab therapy. Despite the beneficial clinical effect of infliximab, there was no significant change in bone mineral density Z-scores after one year of treatment.
  
  
  CONCLUSIONS
  Infliximab may beneficially affect bone homeostasis. Moreover, seasonal variability in vitamin D levels observed prior to initiation of infliximab treatment was diminished after one year of treatment.
authors.affiliation: 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary.
authors.forename: Dolóresz
authors.initials: D
authors.lastname: Szabó
authors.affiliation: 2nd Department of Pediatrics, Semmelweis University, Budapest, Hungary.
authors.forename: Éva
authors.initials: É
authors.lastname: Hosszú
authors.affiliation: 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary.
authors.forename: András
authors.initials: A
authors.lastname: Arató
authors.affiliation: 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary.
authors.forename: Katalin Eszter
authors.initials: KE
authors.lastname: Müller
authors.affiliation: 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary.
authors.forename: Nóra
authors.initials: N
authors.lastname: Béres
authors.affiliation: 1st Department of Medicine, Semmelweis University, Budapest, Hungary.
authors.forename: Péter László
authors.initials: PL
authors.lastname: Lakatos
authors.affiliation: Institute of Internal Medicine, Department of Gastroenterology, University of Debrecen, Clinical Center, Debrecen, Hungary.
authors.forename: Mária
authors.initials: M
authors.lastname: Papp
authors.affiliation: 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary.
authors.forename: Antal
authors.initials: A
authors.lastname: Dezsőfi
authors.affiliation: 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary; MTA-SE, Pediatrics and Nephrology Research Group, Budapest, Hungary.
authors.forename: Attila J
authors.initials: AJ
authors.lastname: Szabó
authors.affiliation: Department of Pediatrics and Paediatric Health Care Center, University of Szeged, Faculty of Medicine, Szeged, Hungary.
authors.forename: Dániel
authors.initials: D
authors.lastname: Szűcs
authors.affiliation: 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary. Electronic address: veres.gabor@med.semmelweis-univ.hu.
authors.forename: Gabor
authors.initials: G
authors.lastname: Veres
mesh_terms: D000293:Adolescent; D015519:Bone Density / Q000187:drug effects; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism; D002648:Child; D003424:Crohn Disease / Q000097:blood* / Q000188:drug therapy*; D005260:Female; D005765:Gastrointestinal Agents / Q000494:pharmacology*; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D000069285:Infliximab / Q000494:pharmacology*; D008297:Male; D015675:Osteocalcin / Q000097:blood; D011446:Prospective Studies; D012621:Seasons; D012720:Severity of Illness Index; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D005765:Gastrointestinal Agents; D015675:Osteocalcin; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D000069285:Infliximab
keywords: Bone markers; Bone mineral density; Crohn's disease; Infliximab; Paediatric; Vitamin D