Smoking in inflammatory bowel diseases: Good, bad or ugly?

Abstract

Smoking is an important environmental factor in inflammatory bowel disease (IBD), having different effects in ulcerative colitis (UC) and Crohn's disease (CD). A recent meta-analysis partially confirmed previous findings that smoking was found to be p r o t e c t i v e a g a i n s t u l c e r a t i v e c o l i t i s a n d , a f t e r onset of the disease, might improve its course, d e c r e a s i n g t h e n e e d f o r c o l e c t o m y . H o w e v e r , smoking increases the risk of developing Crohn's disease and worsens its course, increasing the need for steroids, immunosuppressants and re-operations. Smoking cessation aggravates ulcerative colitis and improves Crohn's disease. Data are however, largely conflictive as well as the potential mechanisms involved in this dual relationship are still unknown. In this review article, the authors review the role of smoking in inflammatory bowel diseases.

The changing pattern of Crohn’s disease incidence in northern France: a continuing increase in the 10- to 19-year-old age bracket (1988-2007)

“…The increase in CD incidence in the 10–19 years group could also reflect an earlier presentation of CD in predisposed patients as proportion of familial history of CD increased and at the same time proportions of extra intestinal manifestations and anoperineal lesions decreased between 1988 and 2007. It might be hypothesised that, in Northern France over time, a change in smoking habits, a well‐known risk factor for CD, 24 would explain the differential evolution in incidence rates of CD according to age. However, accurate regional data supporting this hypothesis are scarce.…”

Smoking status and response to thiopurines in steroid-dependent inflammatory bowel disease

“…Among the former, active smoking has been associated with an increased risk of flare‐up, immunomodulator and surgical requirements, and a more aggressive disease course, with more frequent penetrating intestinal complications and higher rates of postoperative recurrence. Conversely, UC runs a more benign course in smokers, with reduced rates of hospital admission, steroid requirements, proximal progression of the disease, and colectomy 5, 6. Despite this information, scarce data are available about the influence of smoking on the efficacy of a particular drug or on disease course once immunomodulators or biologicals have been started.…”

Interaction between seroreactivity to microbial antigens and genetics in Crohn’s disease: is there a role for defensins?

“…After univariate analysis for the different genotypes, a multivariate logistic regression analysis was performed to correct for those factors that appeared significant in univariate analysis. Each variable with a P ≤ 0.1 identified in univariate association testing was included in the binary logistic regression models, while gender and smoking status were a priori selected as additional variables to be included in these tests regardless of their P value because recent evidence suggests an influence of these factors on disease phenotype and/or genetics (21, 31). Binary codes were used unless stated otherwise.…”