P615 Does smoking really influence the development and the outcomes of Inflammatory Bowel Disease in Asian population? Results from the Taiwanese patients

Chen, B.C.(1);Weng, M.T.(2);Chang, C.H.(3);Huang, L.Y.(4);Wei, S.C.(2);

(1)National Taiwan University, School of Medicine- College of Medicine, Taipei, Taiwan- Province Of China;(2)National Taiwan University Hospital, Department of Internal Medicine, Taipei, Taiwan- Province Of China;(3)National Taiwan University Hospital, Department of Medical Research, Taipei, Taiwan- Province Of China;(4)National Taiwan University Hospital, Clinical Trial Center, Taipei, Taiwan- Province Of China


Smoking has been reported to be associated with increased risk of Crohn’s disease (CD) and protect against ulcerative colitis (UC) from the Western population. However, the association are not well studied and there is no report about smoking and disease outcomes in the Asian population. This study is to clarify the influence of smoking in the development and disease outcomes of inflammatory bowel disease (IBD) in Asian population.


This case-controlled study was conducted by cross section chart review for smoking status as well as clinical characteristics of IBD patients at the National Taiwan University Hospital (NTUH). Age, sex, co-morbidities (hypertension, diabetes, and hyperlipidemia) matched non-IBD control were identified by using the database from the National Health Interview Survey of Taiwan, with 4 to 1 ratio for IBD patients. Clinical characteristics including disease phenotype, medication usage, times of admissions, times of emergency room (ER) visits, surgery, development of new cancer, survival status, endoscopic severity, laboratory data were retrieved and analyzed.


A total of 700 IBD patients (UC: 412; CD: 378) diagnosed from January 1963 to 2020 were identified and analyzed for the influence of smoking to outcomes. The median follow-up time of UC and CD was 104 and 85 months, respectively. Among them, 575 patients (UC: 297, CD: 278) with complete information of comorbidities and aged from 12 to 64 years old were enrolled for smocking prevalence analysis. The prevalence of smoking was significantly lower in UC compared to the matched control (20.88% vs 30.39%, p = 0.0003), but there was no difference between CD and the matched control (19.78% vs 22.12%, p = 0.595). UC smokers were associated with less times of admission (1.56 vs. 2.46, p = 0.017), but higher rate of new cancer development (16% vs. 6.67%, p = 0.01), and mortality (16% vs. 4.91%, p = 0.001), when compared to the non-smokers. CD smokers tended to have disease located in terminal ileum (L1) and ileocolon (L3) (p = 0.0067), higher rate of stricturing (B2) and penetrating (B3) disease (p = 0.0328), higher risk of surgery (60.32% vs. 38.27%, p = 0.001) than the non-smokers, but no difference on mortality.


In Asian IBD population, smoking is a protective factor for UC occurrence and associated with lower hospitalization rate but more cancer and higher mortality. In contrast, smoking has no effect for CD occurrence and mortality but related to more aggressive behavior which resulted in higher surgical rate.