title: U.S. Patients with Ulcerative Colitis Do Not Have a Decreased Risk of Diverticulosis.
abstract: BACKGROUND
  Studies outside the United States have described a lower prevalence of diverticulosis in patients with inflammatory bowel disease (IBD) than in patients without IBD. The aim of this study was to assess the prevalence of diverticulosis and associated risk factors in patients with ulcerative colitis (UC) at a U.S. tertiary care center.
  
  
  METHODS
  We performed a retrospective review of patients over 50 years of age who underwent screening or surveillance colonoscopy from January 2006 to December 2013. We first assessed the prevalence of diverticulosis in patients with UC compared with patients without IBD. Then, we performed a nested case-control study comparing UC patients with diverticulosis (cases) with UC patients without diverticulosis (controls).
  
  
  RESULTS
  We identified 544 patients with UC and 16,705 patients without IBD who underwent colonoscopy. On univariate analysis, 23.5% of patients with UC had diverticulosis, and 46.7% of patients without IBD had diverticulosis, P < 0.01 and relative risk = 0.50 (95% CI, 0.43-0.58). Multivariate analysis adjusting for age and gender found a relative risk of diverticulosis in UC = 1.02 (95% CI, 1.02-1.03). In the nested case-control study, there were no differences between UC cases and UC controls in disease duration (16.7 versus 18.7 yr; P = 0.27), extent of disease (pancolitis 50% versus 60.1%; P = 0.24), obesity (34.5% versus 29.2%; P = 0.40), or ethnicity (86.3% white versus 79.8%; P = 0.20). There was a trend toward history of smoking in patients with UC and diverticulosis (49.5% versus 35.5%; P = 0.09).
  
  
  CONCLUSIONS
  In this U.S.-based study, patients with UC had a slightly increased of diverticulosis compared with patients without IBD undergoing screening or surveillance colonoscopy. There were no identified predictors for diverticular disease in patients with UC, but there was a trend toward previous smoking status and development of diverticulosis. These results are different than previously reported data in patients with IBD in other countries and may represent unique dietary differences that contribute to the development of diverticulosis.
authors.affiliation: Inflammatory Bowel Disease Center, University of Chicago Medicine, Chicago, Illinois.
authors.forename: Jami
authors.initials: J
authors.lastname: Kinnucan
authors.forename: Justin
authors.initials: J
authors.lastname: Tomal
authors.forename: David T
authors.initials: DT
authors.lastname: Rubin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003093:Colitis, Ulcerative / Q000150:complications* / Q000473:pathology; D003113:Colonoscopy; D004240:Diverticulum / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D012907:Smoking; D013997:Time Factors; D014481:United States / Q000453:epidemiology