Epidemiology of the idiopathic inflammatory bowel diseases (Crohn's disease and ulcerative colitis). Epidemiology, the study of patterns of disease occurrence, may yield clues to the cause of, or risk factors associated with, these diseases. We have characterized the incidence cohorts of Olmsted County, Minnesota residents diagnosed with ulcerative colitis and Crohn's disease between 1940-2001. Ongoing studies of this cohort include inquiry into risk factors, as well as collection of serum and blood samples to better define these cohorts in terms of subclinical phenotypes such as antineutrophil cytoplasmic antibodies and antibodies to saccharomyces cerevisae. We have also described various aspects of "natural history" and complications of these population-based inception cohorts (e.g., risk of lymphoma, risk of fractures, clinical course of fistulizing Crohn's disease, etc.).

Pharmacoeconomics of the idiopathic inflammatory bowel diseases. We have used the actual clinical course and direct medical charges of our regional IBD cohorts to develop a Markov model that estimates the medical charges associated with various disease severity states of inflammatory bowel disease. We have been able to estimate the lifetime medical charges associated with Crohn's disease (undiscounted charges, approximately $250,000). Further study into the cost associated with the evaluation and treatment of patients with inflammatory bowel disease will aid in the determination of cost effectiveness of various therapies.

Risk of Cancer in Inflammatory Bowel Disease

We have determined the relative and absolute risk of intestinal cancer in this population-based cohort. We have also performed epidemiological studies to identify risk factors and protective factors for the development of colorectal cancer and dysplasia in these patients.