EPIDEMIOLOGY OF INFLAMMATORY BOWEL-DISEASE

Descriptive surveys of the epidemiology of inflammatory bowel disease from the north and south of Europe show north-south gradient in its in cidence and continue to point to lifestyle and environmental causes. T his theme is further examined in studies of the causal association bet ween inflammatory bowel disease and smoking, oral contraceptive use, a nd diet by investigators from the United States and Europe, but the re sults are not conclusive. Childhood exposure to environmental tobacco smoke and the risk of ulcerative colitis is a new entry to the field t hat shows decreased risk of ulcerative colitis in passive smokers.