Systematic review with meta‐analysis: the adverse effects of tobacco smoking on the natural history of Crohn's disease

Summary Background Tobacco smoking is a well‐established risk factor for the development of Crohn's disease, and this may lead to a more complicated disease course. However, recent evidence suggests that many patients with Crohn's disease are unaware of this fact. Aim To perform a systematic review and meta‐analysis of the effects of smoking on disease course in Crohn's disease. Methods A search of MEDLINE , EMBASE and EMBASE classic was carried...