Effects of current cigarette smoking on clinical course of Crohn's diseaseand ulcerative colitis

Cigarette smoking worsens Crohn's disease (CD) but ameliorates ulcerative c olitis (UC). In Israel, where there is no epidemiological association of sm oking with CD, we examined the effects of current smoking on the course of CD and UC. Patients at nine public hospitals completed a questionnaire deta iling their smoking history, disease course and treatments; subjects alteri ng their smoking habit after the onset of disease were excluded. Sixty-four smokers and 144 nonsmokers had CD, and 34 smokers and 158 nonsmokers had U C. No differences were found between CD smokers and nonsmokers for hospital izations, operations, and requirement for corticosteroid and immunosuppress ive treatment. By contrast, UC smokers had less extensive disease than nons mokers (P < 0.02) and fewer hospitalizations (P = 0.01) and operations (P = 0.025). Our results agree with a minority of studies showing no adverse ef fect of smoking on the course of CD, and confirm the protective effect of s moking in UC.