ENVIRONMENTAL RISK-FACTORS IN INFLAMMATORY BOWEL-DISEASE

Besides a genetic predisposition, a causal role of various environment al factors have been taken into consideration, in. the etiology of inf lammatory bowel disease (IBD). The most consistent association of envi ronmental factors so far identified is the association between non smo king and ulcerative colitis (UC) as roell as between smoking and Crohn 's disease (CD). Other factors such as oral contraceptives, refined su gar, perinatal events, childhood infections, microbial agents, and dom estic hygiene have been found to be associated with ulcerative colitis and Crohn's disease but further evaluation is required to confirm the consistency and to define the strength of the association. Recent dat a also suggest that measles virus may persist in intestinal tissue and early exposure to the virus may be a risk factor for development of C D. The further investigation of environmental factors on IBD and the e xplanation of their role is expected to open new avenues for basic sci entific research and may lead to the development of a more rational ap proach to the prevention and treatment of IBD. The available data sugg est that UC and CD are heterogeneous disorders of multifactorial etiol ogy in which hereditary and environmental factors interact to produce the disease.