title: Vitamin D deficiency in patients with inflammatory bowel disease: association with disease activity and quality of life.
abstract: BACKGROUND
  Vitamin D deficiency is common in inflammatory bowel disease (IBD). The aim of the study was to determine the prevalence and predictors of vitamin D deficiency in an IBD cohort. It was hypothesized that vitamin D deficiency is associated with increased disease activity and lower health-related quality of life (HRQOL).
  
  
  METHODS
  This was a retrospective cohort study. Harvey-Bradshaw index and ulcerative colitis disease activity index were used to assess disease activity. Short Inflammatory Bowel Disease Questionnaire scores were used to assess HRQOL. Multivariate logistic regression was used to identify independent predictors of vitamin D deficiency and its association with disease activity and HRQOL.
  
  
  RESULTS
  The study included 504 IBD patients (403 Crohn's disease [CD] and 101 ulcerative colitis [UC]) who had a mean disease duration of 15.5 years in CD patients and 10.9 years in UC patients; 49.8% were vitamin D deficient, with 10.9% having severe deficiency. Vitamin D deficiency was associated with older age (P = .004) and older age at diagnosis (P = .03). Vitamin D deficiency was associated with lower HRQOL (regression coefficient -2.21, 95% confidence interval [CI], -4.10 to -0.33) in CD but not UC (regression coefficient 0.41, 95% CI, -2.91 to 3.73). Vitamin D deficiency was also associated with increased disease activity in CD (regression coefficient 1.07, 95% CI, 0.43 to 1.71).
  
  
  CONCLUSIONS
  Vitamin D deficiency is common in IBD and is independently associated with lower HRQOL and greater disease activity in CD. There is a need for prospective studies to assess this correlation and examine the impact of vitamin D supplementation on disease course.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA. alex.ulitsky@gmail.com
authors.forename: Alex
authors.initials: A
authors.lastname: Ulitsky
authors.forename: Ashwin N
authors.initials: AN
authors.lastname: Ananthakrishnan
authors.forename: Amar
authors.initials: A
authors.lastname: Naik
authors.forename: Sue
authors.initials: S
authors.lastname: Skaros
authors.forename: Yelena
authors.initials: Y
authors.lastname: Zadvornova
authors.forename: David G
authors.initials: DG
authors.lastname: Binion
authors.forename: Mazen
authors.initials: M
authors.lastname: Issa
mesh_terms: D000328:Adult; D000367:Age Factors; D015331:Cohort Studies; D003093:Colitis, Ulcerative / Q000150:complications*; D003424:Crohn Disease / Q000150:complications*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D015995:Prevalence; D011788:Quality of Life; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D014808:Vitamin D Deficiency / Q000150:complications* / Q000453:epidemiology