P871 Consideration of smoking and familial aggregation of appendectomy together may change our previous belief about the influence of appendectomy in Inflammatory Bowel Disease (Ulcerative Colitis vs Crohn's Disease).
Bakkaloglu, O.K.(1)*;Eskazan, T.(1);Onal, U.(1);Candan, S.(1);Balamir, M.(1);Kurt, E.A.(1);Hatemi, I.(1);Erzin, Y.(1);Celik, A.F.(1);
(1)Istanbul University Cerrahpasa, Gastroenterology, istanbul, Turkey;
Background
While appendectomy is known to be associated with Crohn's Disease (CD), it is claimed to be protective against Ulcerative Colitis (UC). However, it is not clear whether this is a cause-effect relationship or is due to different inflammatory and genetic characteristics of the two different diseases. The discrete effects of smoking on the course of CD and UC are well known. Yet, the familial aspect of appendectomy in IBD patients and its relationship with smoking have not been discussed before.
Methods
The frequency of appendectomy, smoking status of the patients (never / ever smoker) and their relations with each other were evaluated in 227 CD, 180 UC patients and their families (including biological parents and children).
Results
58% of the patients were male and the median age in the whole group was 42 years (Table-1). Age was found to be higher in UC patients compared to CD (44-40 p:0.002). The frequency of appendectomy in the whole group was 16.5%; It was 6.7% in UC and 24.8% in CD (p:0.001) (Reference prevalence of appendectomy in normal population is reported as %7). Age was higher in patients with appendectomy compared to IBD patients without appendectomy (45-41 p:0.08). Smoking was detected more frequently in both CD patients, and IBD patients with appendectomy (both p<0.001). The risk of appendectomy in IBD patients was associated with a family history of appendectomy (31%-15% p:0.005). Similar to the increased incidence of appendectomy in CD patients, family history of appendectomy in IBD patients was associated with a family history of CD, but this relationship could not be demonstrated for UC. The frequency of appendectomy in families of CD patients was higher than in families of UC patients (22%-15% p:0.07). In the regression analysis, CD, smoking and increasing age were found to be independently associated with appendectomy in IBD patients (Table 2).
Conclusion
The co-occurrence of CD and appendectomy, compared to UC, and the relationship between appendectomy and family history suggest that similar genetic factors and ultimately inflammatory pathways may be effective in both diseases. The association of smoking with increased CD and appendectomy frequencies, together with its paradoxical effect on UC, suggests that smoking may be a triggering factor on inflammatory pathways in some individuals with this genetic background. These results may also jeopardize the recently claimed protective role of appendectomy on UC.