Ulcerative colitis appears to be slightly more common than Crohn's disease.
The rate of IBD is increasing in Western cultures whereas it is virtually unknown in countries where people eat less refined foods. IBD can occur at any age but it is most common in those aged from 15 to 35. Symptoms Ulcerative colitis causes inflammation and ulceration of the inner lining of the large bowel. The most common early symptoms are constipation with passage of blood or mucus in the stools. It may be months or years before diarrhea and abdominal pains develop.