title: Normalization of plasma 25-hydroxy vitamin D is associated with reduced risk of surgery in Crohn's disease.
abstract: BACKGROUND
  Vitamin D may have an immunologic role in Crohn's disease (CD) and ulcerative colitis (UC). Retrospective studies suggested a weak association between vitamin D status and disease activity but have significant limitations.
  
  
  METHODS
  Using a multi-institution inflammatory bowel disease cohort, we identified all patients with CD and UC who had at least one measured plasma 25-hydroxy vitamin D (25(OH)D). Plasma 25(OH)D was considered sufficient at levels ≥30 ng/mL. Logistic regression models adjusting for potential confounders were used to identify impact of measured plasma 25(OH)D on subsequent risk of inflammatory bowel disease-related surgery or hospitalization. In a subset of patients where multiple measures of 25(OH)D were available, we examined impact of normalization of vitamin D status on study outcomes.
  
  
  RESULTS
  Our study included 3217 patients (55% CD; mean age, 49 yr). The median lowest plasma 25(OH)D was 26 ng/mL (interquartile range, 17-35 ng/mL). In CD, on multivariable analysis, plasma 25(OH)D <20 ng/mL was associated with an increased risk of surgery (odds ratio, 1.76; 95% confidence interval, 1.24-2.51) and inflammatory bowel disease-related hospitalization (odds ratio, 2.07; 95% confidence interval, 1.59-2.68) compared with those with 25(OH)D ≥30 ng/mL. Similar estimates were also seen for UC. Furthermore, patients with CD who had initial levels <30 ng/mL but subsequently normalized their 25(OH)D had a reduced likelihood of surgery (odds ratio, 0.56; 95% confidence interval, 0.32-0.98) compared with those who remained deficient.
  
  
  CONCLUSIONS
  Low plasma 25(OH)D is associated with increased risk of surgery and hospitalizations in both CD and UC, and normalization of 25(OH)D status is associated with a reduction in the risk of CD-related surgery.
authors.affiliation: Division of Gastroenterology, Massachusetts General Hospital, Boston, MA 02114, USA. aananthakrishnan@partners.org
authors.forename: Ashwin N
authors.initials: AN
authors.lastname: Ananthakrishnan
authors.forename: Andrew
authors.initials: A
authors.lastname: Cagan
authors.forename: Vivian S
authors.initials: VS
authors.lastname: Gainer
authors.forename: Tianxi
authors.initials: T
authors.lastname: Cai
authors.forename: Su-Chun
authors.initials: SC
authors.lastname: Cheng
authors.forename: Guergana
authors.initials: G
authors.lastname: Savova
authors.forename: Pei
authors.initials: P
authors.lastname: Chen
authors.forename: Peter
authors.initials: P
authors.lastname: Szolovits
authors.forename: Zongqi
authors.initials: Z
authors.lastname: Xia
authors.forename: Philip L
authors.initials: PL
authors.lastname: De Jager
authors.forename: Stanley Y
authors.initials: SY
authors.lastname: Shaw
authors.forename: Susanne
authors.initials: S
authors.lastname: Churchill
authors.forename: Elizabeth W
authors.initials: EW
authors.lastname: Karlson
authors.forename: Isaac
authors.initials: I
authors.lastname: Kohane
authors.forename: Robert M
authors.initials: RM
authors.lastname: Plenge
authors.forename: Shawn N
authors.initials: SN
authors.lastname: Murphy
authors.forename: Katherine P
authors.initials: KP
authors.lastname: Liao
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D003093:Colitis, Ulcerative / Q000097:blood / Q000209:etiology / Q000601:surgery*; D003424:Crohn Disease / Q000097:blood / Q000209:etiology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors; D062606:Tertiary Care Centers; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications / Q000601:surgery*
chemical_list: D015415:Biomarkers; D014807:Vitamin D; C104450:25-hydroxyvitamin D