Impact of cessation of smoking on the course of ulcerative colitis.

OBJECTIVES: The incidence and severity of ulcerative colitis (UC) are higher in nonsmokers than in smokers. The natural course of UC in smokers who stop smoking is not known. The aim of this study was to determine the impact of cessation of smoking on the course of UC among the cohort of patients regularly seen at our institution. METHODS: The severity of UC, as judged by the occurrence of flare-ups and the need for systemic steroids, immunosuppressive drugs and colectomy, was determined in 32 patients with UC who stopped smoking after the diagnosis of UC. We compared the period after cessation of smoking (7-yr mean follow-up) with the period between the onset of the disease and the cessation of smoking (9-yr mean duration). The course of UC in this group was compared with that of 32 nonsmokers and 32 continuing smokers matched for sex, age, and age at onset. RESULTS: In patients who quit, cessation of smoking was followed by an increase in the rate of years with active disease (p < 0.01), years with hospitalization (p < 0.05) and years with major medical therapy (oral steroids, intravenous steroids, and azathioprine, p < 0.01). After cessation of smoking, the rate of years with immunosuppressive therapy was significantly greater in ex-smokers and nonsmokers than in continuing smokers (p < 0.01). The risk of colectomy in ex-smokers after smoking cessation was similar to that of nonsmokers and continuing smokers. CONCLUSIONS: In smokers with UC who stop smoking, the severity of the disease increases after smoking cessation, with an increase in the disease activity and the need for hospital admission and major medical therapy. In addition, the need for azathioprine therapy becomes similar to that of nonsmokers.