Epidemiology of inflammatory bowel disease

The year of 1996 became a year of collaborative efforts with regard to the epidemiologic features of inflammatory bowel disease. In a collaborative study of the annual incidence of inflammatory bowel disease from 20 European centers, authors were able to compare the incidence rates in different populations in which the cases had been ascertained in a uniform manner. The authors were also able to show a north-south gradient, although it was less prominent than expected after taking into account the results from previous studies. The genetics of inflammatory bowel disease were explored in collaborative studies as well as studies from individual centers, all of which were highlighted in an issue of Gastroenterology in which five different studies were presented. A Crohn's disease susceptibility locus on chromosome 16 was identified, and differences in the clinical features in familial and sporadic cases of inflammatory bowel disease were analyzed. Although the question of whether familial cases consistute a specific subgroup still remains to be settled in a definitive way, there are strong indications of a genetic anticipation in inflammatory bowel disease, especially in Crohn's disease.