ABSTRACT
The incidence of UC varies by geographical location. It is most common in Western nations and incidence in the United States is estimated at 8 to 12/100,000 population per year (18). Unlike CD, the incidence of UC has remained stable over the past several decades (18). Smoking and even a history of smoking increases the risk of UC. Former smokers have a 1.7-fold increased risk of developing UC compared to nonsmokers (1).
Etiology/Basic Pathophysiology The etiology of UC remains unknown. The pathogenesis is currently thought to be similar to CD (see section “Etiology/ Basic Pathophysiology” described earlier for CD).
