Ulcerative colitis is a chronic inflammatory bowel disease that is characterized by inappropriate diffuse inflammation of the rectal and colonic mucosa, which occurs in the innermost layer of the intestinal lining. Ulcerative colitis is a chronic, incurable disease with low mortality that is generally diagnosed in adolescence and early adulthood.
Ulcerative colitis is currently an idiopathic condition, the pathogenesis of which is yet to be fully elucidated. However, it is known to involve an interaction between genetics, the immune system, and environmental factors. Risk factors include ethnicity, family history, antibiotic or non-steroidal anti-inflammatory agent use, and diet. Incidence and prevalence have been increasing over the past two decades in most regions of the world.
It is estimated that in 2015, there were 2.1 million diagnosed prevalent cases of ulcerative colitis in the US, Japan, and five major EU markets (France, Germany, Italy, Spain, and the UK). Over 2015-35, the number of prevalent cases is expected to increase to 2.5 million (16.6% increase).