Epidemiology of IBD

Ulcerative Colitis Crohn's Disease Incidence (North America) per person-years 2.2–14.3:100,000 3.1–14.6:100,000 Age of onset 15–30 & 60–80 15–30 & 60–80 Ethnicity Jewish > non-Jewish white > African American > Hispanic > Asian Male/female ratio 1:1 1.1–1.8:1 Smoking May prevent disease May cause disease Oral contraceptives No increased risk Odds ratio 1.4 Appendectomy Protective Not protective Monozygotic twins 6% concordance 58% concordance Dizygotic twins 0% concordance 4% concordance