title: Inflammatory bowel disease and cervical neoplasia: a population-based nationwide cohort study.
abstract: OBJECTIVE
  We examined the risk of cervical neoplasia (dysplasia or cancer) in women with ulcerative colitis (UC) or Crohn's disease (CD). We also calculated the reverse, the risk for diagnosis with cervical neoplasia before development of inflammatory bowel disease (IBD).
  
  
  METHODS
  We established a national cohort of women diagnosed with UC (n = 18,691) or CD (n = 8717) between 1979 and 2011 and a control cohort of individually matched women from the general population (controls, n = 1,508,334). Incidence rate ratios (IRRs) of screening activity and diagnosis of cervical neoplasia in women with IBD were assessed by Cox proportional hazards regression analysis. Odds ratios (ORs) of cervical neoplasia before diagnosis of IBD were calculated by using conditional logistic regression.
  
  
  RESULTS
  Women with CD underwent cervical cancer screening as often as women in the general population (IRR, 0.99; 95% confidence interval [CI], 0.96-1.02), whereas screening frequency was slightly increased in women with UC (IRR, 1.06; 95% CI, 1.04-1.08). A total of 561 patients with UC were diagnosed with dysplasia during a median follow-up time of 7.8 years, and 28 patients with UC developed cervical cancer, compared with 1918 controls. A total of 407 patients with CD were diagnosed with dysplasia during a median follow-up time of 8.3 years, and 26 patients with CD developed cervical cancer, compared with 940 controls. Patients with UC had increased risk of low-grade (IRR, 1.15; 95% CI, 1.00-1.32) and high-grade (IRR, 1.12; 95% CI, 1.01-1.25) squamous intraepithelial lesions (SILs), whereas patients with CD had increased risks of low-grade SIL (IRR, 1.26; 95% CI, 1.07-1.48), high-grade SIL (IRR, 1.28; 95% CI, 1.13-1.45), and cervical cancer compared with controls (IRR, 1.53; 95% CI, 1.04-2.27). ORs for cervical cancer were also increased 1-9 years before diagnosis of UC, compared with women without UC (OR, 2.78; 95% CI, 2.12-3.64) or CD (OR, 1.85; 95% CI, 1.08-3.15).
  
  
  CONCLUSIONS
  In a population-based nationwide cohort study, we found a 2-way association between IBD, notably CD, and neoplastic lesions of the uterine cervix. This observation is not explained by differences in screening activity.
authors.affiliation: Department of Epidemiology Research, Statens Serum Institut, Copenhagen.
authors.forename: Christine
authors.initials: C
authors.lastname: Rungoe
authors.affiliation: Department of Epidemiology Research, Statens Serum Institut, Copenhagen.
authors.forename: Jacob
authors.initials: J
authors.lastname: Simonsen
authors.affiliation: Department of Pathology, Herlev University Hospital, Copenhagen.
authors.forename: Lene
authors.initials: L
authors.lastname: Riis
authors.affiliation: Department of Epidemiology Research, Statens Serum Institut, Copenhagen.
authors.forename: Morten
authors.initials: M
authors.lastname: Frisch
authors.affiliation: Department of Internal Medicine, Gentofte University Hospital, Copenhagen.
authors.forename: Ebbe
authors.initials: E
authors.lastname: Langholz
authors.affiliation: Department of Epidemiology Research, Statens Serum Institut, Copenhagen; Department of Clinical Epidemiology, University of Aalborg, Aalborg, Denmark. Electronic address: tjs@ssi.dk.
authors.forename: Tine
authors.initials: T
authors.lastname: Jess
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D015212:Inflammatory Bowel Diseases / Q000150:complications* / Q000453:epidemiology*; D008875:Middle Aged; D018570:Risk Assessment; D002583:Uterine Cervical Neoplasms / Q000150:complications* / Q000453:epidemiology*; D055815:Young Adult
keywords: Cancer Risk Factor; Neoplasia; Thiopurines; Treatment