title: Appendectomy, smoking habits and the risk of developing ulcerative colitis: a case control study in private practice setting.
abstract: OBJECTIVE
  The strongest environmental factors identified for ulcerative colitis (UC) are cigarette smoking and appendectomy. However, most studies have been performed using case-controls from hospital-based populations. The purpose of this study was to compare the history of previous appendectomy and smoking habits in a group of patients with UC and a control group, followed by gastroenterologists in private practice.
  
  
  METHODS
  We performed a case control study in which 100 physicians recruited UC-patients and age and sex matched controls. Data were collected during a single visit. Based on a standardized questionnaire, UC patients and controls were divided into never, former or current smokers, and into subjects with or without a previous history of appendectomy.
  
  
  RESULTS
  One hundred and ninety eight age- and sex-matched pairs of UC patients and controls were included. The prevalence of appendectomy in the UC-patients and control group was 12% and 46%, respectively. The pairwise-matched OR of ulcerative colitis for previous appendectomy was 0.10 (95% CI, 0.05-0.21) (P<0.0001). The OR for former and never smokers versus current smokers was 2.40 (95% CI 1.31-4.38) (P=0.004). In UC-patients, the OR of family history of UC compared with controls was 2.80 (95% CI, 1.01-7.77) (P=0.048).
  
  
  CONCLUSIONS
  This case-control study confirmed a strong negative correlation between both appendectomy and tobacco smoking, and ulcerative colitis in patients followed-up by gastroenterological practitioners.
authors.affiliation: Division de Gastroentérologie et d'Hépatologie, Hôpitaux Universitaires de Genève, Genève, Suisse.
authors.forename: Philippe
authors.initials: P
authors.lastname: de Saussure
authors.forename: Pierre
authors.initials: P
authors.lastname: Clerson
authors.forename: Pierre-Louis
authors.initials: PL
authors.lastname: Prost
authors.forename: Nghiep
authors.initials: N
authors.lastname: Truong Tan
authors.forename: Yoram
authors.initials: Y
authors.lastname: Bouhnik
authors.lastname: Gil-Rch
mesh_terms: D000328:Adult; D001062:Appendectomy; D016022:Case-Control Studies; D003093:Colitis, Ulcerative / Q000209:etiology* / Q000235:genetics; D003113:Colonoscopy; D003424:Crohn Disease / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008297:Male; D012008:Recurrence; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*
chemical_list: D005938:Glucocorticoids; D007166:Immunosuppressive Agents