Passive smoking in patients with inflammatory bowel disease: an Israeli multicentre case-control study

Background The association between smoking and inflammatory bower disease ( IBD) is well established. There are, however, no large scale studies of pas sive smoking in inflammatory bowel disease and this has never been surveyed in the Jewish population of Israel. Aim To study the passive smoking exposure of Jewish IBD patients in Israel in a large scale multicentre study. Methods Patients with established IBD, aged 18-70 years, were interviewed r egarding smoking and other habits. Two controls, one clinic and one neighbo urhood, matched by age, sex, community group, and education, were sought fo r each subject. Results Five hundred and thirty-four patients (273 ulcerative colitis (UC) and 261 Crohn's disease (CD)), 478 clinic controls and 430 community contro ls were interviewed. There were no significant differences in the passive s moking habits between IBD patients and their controls. Fifty-one percent of UC patients, 50% of the clinic controls and 58% of the community controls were exposed to passive smoking at home (NS); similar results were found am ong CD patients (50%, 55% and 56%, respectively). When a quantitative expos ure index was used UC patients were significantly less exposed to passive s moking than were their community controls (7.46 +/- 8.40 vs 9.36 +/- 9.46, n = 229, P<0.031). There was no difference in the exposure to passive smoki ng among CD patients and their controls. No differences in exposure to pass ive smoking were found when UC patients who had never smoked were compared with their controls. When the quantitative index was used 'never-smoked' CD patients tended to be less exposed to passive smoking at home than their c ommunity controls (5.40 +/- 7.60 vs 8.04 +/- 8.72, P<0.05). Conclusion There is a lack of association between passive smoking and IBD i n Jewish patients in Israel. When a quantitative exposure index was used UC patients were found to be less exposed to passive smoking than their commu nity controls. (C) 2000 Lippincott Williams & Wilkins.