title: Increased risk of nonmelanoma skin cancers among individuals with inflammatory bowel disease.
abstract: OBJECTIVE
  There are limited data on the risk of nonmelanoma skin cancer (NMSC) among individuals with inflammatory bowel disease (IBD), including those with or without exposure to immunosuppressant medications.
  
  
  METHODS
  Individuals with IBD (n = 9618) were identified from the University of Manitoba IBD Epidemiology Database and matched with randomly selected controls (n = 91,378) based on age, sex, and postal area of residence on the date of IBD diagnosis (index date). Groups were followed up from the index date until a diagnosis of any invasive cancer (including NMSC), death, migration from the province, or the end of the study (December 31, 2009), whichever came first. Cox regression analysis was performed to calculate the relative risk of NMSC among the individuals with IBD, adjusting for frequency of ambulatory care visits and socioeconomic status.
  
  
  RESULTS
  Of the individuals followed, 1696 were diagnosed with basal cell skin cancer (BCC) and 341 were diagnosed with squamous cell skin cancer (SCC). Individuals with IBD had an increased risk for BCC, compared with controls (hazard ratio, 1.20; 95% confidence interval [CI], 1.03-1.40). Among patients with IBD, use of thiopurines increased the risk of SCC (hazard ratio, 5.40; 95% CI, 2.00-14.56), compared with controls. Use of thiopurines also was associated with SCC in a case-control, nested analysis of individuals with IBD (odds ratio, 20.52; 95% CI, 2.42-173.81).
  
  
  CONCLUSIONS
  The risk of BCC could be increased among individuals with IBD. Use of thiopurines increases the risk of SCC among individuals with IBD.
authors.affiliation: Internal Medicine, University of Manitoba, Winnipeg, Manitoba, Canada. singh@cc.umanitoba.ca
authors.forename: Harminder
authors.initials: H
authors.lastname: Singh
authors.forename: Zoann
authors.initials: Z
authors.lastname: Nugent
authors.forename: Alain A
authors.initials: AA
authors.lastname: Demers
authors.forename: Charles N
authors.initials: CN
authors.lastname: Bernstein
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects / Q000627:therapeutic use; D015212:Inflammatory Bowel Diseases / Q000150:complications* / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D018295:Neoplasms, Basal Cell / Q000453:epidemiology*; D018307:Neoplasms, Squamous Cell / Q000453:epidemiology*; D015995:Prevalence; D011687:Purines / Q000009:adverse effects / Q000627:therapeutic use; D012307:Risk Factors; D012878:Skin Neoplasms / Q000453:epidemiology*
chemical_list: D000305:Adrenal Cortex Hormones; D007166:Immunosuppressive Agents; D011687:Purines