title: Crohn's disease and smoking: is it ever too late to quit?
abstract: BACKGROUND
  Smoking increases CD risk. The aim was to determine if smoking cessation at, prior to, or following, CD diagnosis affects medication use, disease phenotypic progression and/or surgery.
  
  
  METHODS
  Data on CD patients with disease for ≥5 yrs were collected retrospectively including the Montreal classification, smoking history, CD-related abdominal surgeries, family history, medication use and disease behaviour at diagnosis and the time when the disease behaviour changed.
  
  
  RESULTS
  1115 patients were included across six sites (mean follow-up-16.6 yrs). More non-smokers were male (p=0.047) with A1 (p<0.0001), L4 (p=0.028) and perianal (p=0.03) disease. Non-smokers more frequently received anti-TNF agents (p=0.049). (p=0.017: OR 2.5 95%CI 1.18-5.16) and those who ceased smoking prior to diagnosis (p=0.045: OR 2.3 95%CI 1.02-5.21) progressed to complicated (B2/B3) disease as compared to those quitting at diagnosis. Patients with uncomplicated terminal ileal disease at diagnosis more frequently developed B2/B3 disease than isolated colonic CD (p<0.0001). B2/B3 disease was more frequent with perianal disease (p<0.0001) and if i.v. steroids (p=0.004) or immunosuppressants (p<0.0001) were used. 49.3% (558/1115) of patients required at least one intestinal surgery. More smokers had a 2nd surgical resection than patients who quit at, or before, the 1st resection and non-smokers (p=0.044: HR=1.39 95%CI 1.01-1.91). Patients smoking >3 cigarettes/day had an increased risk of developing B2/B3 disease (p=0.012: OR 3.8 95%CI 1.27-11.17).
  
  
  CONCLUSIONS
  Progression to B2/B3 disease and surgery is reduced by smoking cessation. All CD patients regardless of when they were diagnosed, or how many surgeries, should be strongly encouraged to cease smoking.
authors.affiliation: Centre for Inflammatory Bowel Diseases, Fremantle Hospital, WA, Australia; University Department of Medicine and Pharmacology, University of Western Australia, Fremantle Hospital, WA, Australia. Electronic address: Ian.Lawrance@uwa.edu.au.
authors.forename: Ian C
authors.initials: IC
authors.lastname: Lawrance
authors.forename: Kevin
authors.initials: K
authors.lastname: Murray
authors.forename: Birol
authors.initials: B
authors.lastname: Batman
authors.forename: Richard B
authors.initials: RB
authors.lastname: Gearry
authors.forename: Rachel
authors.initials: R
authors.lastname: Grafton
authors.forename: Krupa
authors.initials: K
authors.lastname: Krishnaprasad
authors.forename: Jane M
authors.initials: JM
authors.lastname: Andrews
authors.forename: Ruth
authors.initials: R
authors.lastname: Prosser
authors.forename: Peter A
authors.initials: PA
authors.lastname: Bampton
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Cooke
authors.forename: Gillian
authors.initials: G
authors.lastname: Mahy
authors.forename: Graham
authors.initials: G
authors.lastname: Radford-Smith
authors.forename: Anthony
authors.initials: A
authors.lastname: Croft
authors.forename: Katherine
authors.initials: K
authors.lastname: Hanigan
mesh_terms: D000293:Adolescent; D000328:Adult; D001004:Anus Diseases / Q000473:pathology; D003092:Colitis / Q000473:pathology*; D003424:Crohn Disease / Q000473:pathology / Q000628:therapy*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007079:Ileitis / Q000473:pathology*; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008297:Male; D012086:Reoperation; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects*; D016540:Smoking Cessation; D013256:Steroids / Q000627:therapeutic use; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors; D055815:Young Adult
chemical_list: D007166:Immunosuppressive Agents; D013256:Steroids; D014409:Tumor Necrosis Factor-alpha
keywords: Crohn's disease; Disease progression; Smoking; Surgery