P109 SMOKING NEGATIVELY AFFECTS DISEASE COURSE REGARDLESS OF SMOKING AMOUNT AND MAY BE ASSOCIATED WITH PANETH CELL PHENOTYPE IN JAPANESE CROHN’S DISEASE PATIENTS

Abstract

Smoking is a well-known risk factor for Crohn’s disease (CD) onset and aggressive disease course in the Western population. However, previous studies imply that smoking was not associated with an increased risk for CD onset in Asian populations. Therefore, we examined the effect of smoking on the disease course after surgery in Japanese CD patients. Furthermore, we investigated the association between smoking and paneth cell (PC) phenotype, which was recently recognized as a useful biomarker for the disease course of CD. A total of 72 Japanese CD patients who underwent ileal resection were recruited. Patents were classified into three groups by post-operative smoking status; current smoker：patients who continued smoking after surgery; ever smoker：patients who did not smoke after surgery but had smoking history; and non-smoker. Pre and post-operative smoking amount were investigated in current smokers. PC phenotype was determined by defensin 5 immunofluorescence on uninvolved ileal tissue. Correlation with time to recurrence was performed using the log-rank and cox hazard test. Current smoking were significantly associated with early recurrence compared with the other two groups (P=0.0063). There was no significant difference between ever smoker and non-smoker (P=0.643). Moreover, pre and post-operative smoking amount were not associated with recurrence time (P=0.438). Apart from current smoking, first use of biologics and PC phenotype were correlated with early recurrence (P=0.023, 0.0065). Interestingly, patients who were current smokers at the time of the operation tended to have higher proportion of abnormal PC phenotype (P=0.054). Smoking after surgery was shown to negatively affect the disease course regardless of the smoking amount in Japanese CD. Not reduced smoking but nonsmoking should be recommended for CD patients. Furthermore, smoking can affect PC phenotype, which may explain negative effect of smoking on CD.