title: The nondietary determinants of vitamin D status in pediatric inflammatory bowel disease.
abstract: OBJECTIVE
  The aim of this study was to investigate the relationships between 25-hydroxy vitamin D (25[OH]D) and markers of vitamin D status in inflammatory bowel disease (IBD).
  
  
  METHODS
  We conducted a retrospective case-control study of 59 pediatric patients with IBD (age 16.4 ± 2.2 y) and 116 controls (age 14.6 ± 4.4 y), to investigate the association between 25(OH)D and albuminemia for protein-losing enteropathy (PLE) and hepatic dysfunction; alanine transaminase (ALT) for hepatic inflammation; erythrocyte sedimentation rate (ESR) for intestinal inflammation; body mass index (BMI) for adiposity; seasons and skin pigmentation for insolation. Vitamin D deficiency was defined as 25(OH)D < 50 nmol/L; abnormal liver enzyme by ALT >40 U/L; overweight status by BMI of ≥85th but <95th percentile, and obesity by BMI ≥95th percentile. Seasons were categorized as summer, winter, spring, and fall.
  
  
  RESULTS
  Patients with IBD had a higher prevalence of vitamin D deficiency (42.4% versus 26.7%; P = 0.04), elevated ALT (16.9% versus 2.6%; P < 0.001), and lower albumin (41.1 ± 4.8 versus 45.1 ± 3.8; P < 0.001) than controls. In both the IBD cohort and controls, 25(OH)D was highest in summer and lowest in winter, and significantly higher in white than in non-white patients. ESR varied significantly with 25(OH)D (R(2) = 0.24; β = -0.32; P = 0.010), and only patients with IBD with elevated ESR had lower 25(OH)D than controls (49.5 ± 25.2 versus 65.3 ± 28.0 nmol/L; P = 0.045).
  
  
  CONCLUSIONS
  Intestinal inflammation, not the loss of albumin-bound vitamin D in the gut, is the primary intestinal determinant of vitamin D status in IBD. The extraintestinal determinants are seasons and skin pigmentation, but not adiposity and hepatic inflammation.
authors.affiliation: Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA, USA.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Veit
authors.affiliation: Department of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, MA, USA.
authors.forename: Louise
authors.initials: L
authors.lastname: Maranda
authors.affiliation: Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA, USA. Electronic address: benjamin.nwosu@umassmemorial.org.
authors.forename: Benjamin Udoka
authors.initials: BU
authors.lastname: Nwosu
mesh_terms: D050154:Adiposity / Q000276:immunology; D000293:Adolescent; D000410:Alanine Transaminase / Q000097:blood; D000418:Albumins / Q000032:analysis; D001799:Blood Sedimentation; D015992:Body Mass Index; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood; D015212:Inflammatory Bowel Diseases / Q000097:blood* / Q000276:immunology; D008099:Liver / Q000201:enzymology / Q000276:immunology; D008297:Male; D050177:Overweight; D015995:Prevalence; D012189:Retrospective Studies; D012621:Seasons; D012880:Skin Pigmentation; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000418:Albumins; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D000410:Alanine Transaminase
keywords: Adiposity; Alanine transaminase; Crohn's disease; Hepatic inflammation; Hypoalbuminemia; Inflammatory bowel disease; Intestinal inflammation; Protein-losing enteropathy; Ulcerative colitis; Vitamin D