The incidence of ulcerative colitis in North America is 10-12 cases per 100,000, with a peak incidence of ulcerative colitis occurring between the ages of 15 and 25. There is thought to be a bimodal distribution in age of onset, with a second peak in incidence occurring in the 6th decade of life. The disease affects females more than males with highest incidences in the United States, Canada, the United Kingdom, and Scandinavia. Higher incidences are seen in northern locations compared to southern locations in Europe and the United States.
As with Crohn's disease, ulcerative colitis is thought to occur more commonly among Ashkenazi Jewish people than non-Jewish people, although immigrant data from the United States does not support this hypothesis.
