Smoking and Crohn's disease.

In a case-control study 82 patients with Crohn's disease and matched controls drawn from general practice lists were questioned about their smoking habits. Patients with Crohn's disease were significantly more likely to be smokers than the controls, and the association was stronger for smoking habit before the onset of the disease than for current smoking habit, the relative risks for smokers compared with non-smokers being 4.8 and 3.5...