Changes in incidence and clinical features of inflammatory bowel disease in Cardiff, UK over 50 years: an update for 2005-2016.

Incidence of both CD and UC are no longer rising significantly, but the location of CD at diagnosis continues to change with an increase in colonic location.Key messagesWhat is already known? It is unclear whether the incidence of IBD has now plateaued in urbanised nations. Changes in Crohn's disease location are often not reported in incidence studies and terminal ileal disease has usually been reported as the commonest site of diseaseWhat is new here? The incidence of UC and Crohn's is no longer rising in Cardiff UK, but the phenotype has changed progressively over time with a continuing increase in colonic disease location and decrease in isolated terminal ileal diseaseHow can this study help patient care? Understanding that Crohn's colitis is the predominant location has implications for diagnostic tests and implications for treatment optionsIMPACT STATEMENTThis work shows that although IBD incidence is no longer rising, the pattern of Crohn's disease is changing with more colonic disease and less isolated terminal ileal disease.PRACTITIONER RELEVANCE STATEMENTThe changing pattern of Crohn's disease location has implications for diagnostic assessment and treatment of this disease.