may impact these diseases. Risk? WHO IS AT 10 New cases (incidence): A population-based study conducted from 1940 to 2011 in Olmsted County, Minnesota, examined the incidence of IBD. The total number of new cases of Crohn’s disease diagnosed each year (incidence) was 10.7 per 100,000 people, or approximately 33,000 new cases per year. The total number of new cases of ulcerative colitis diagnosed each year was 12.2 per 100,000 people, or approximately 38,000 new cases per year (Figure 3). Existing cases (prevalence): Extrapolating from the Olmsted County study data to the current United States population, approximately 780,000 Americans currently have Crohn’s disease and 907,000 currently have ulcerative colitis. Age: Although Crohn’s disease and ulcerative colitis can occur at any age, people are more frequently diagnosed between the ages of 15 and 35. According to the Olmsted County study, the median age of diagnosis for ulcerative colitis and Crohn’s disease was 34.9 years and 29.5 years respectively (Figures 4 and 5). Gender: In general, IBD affects men and women equally. However, most North American studies show that ulcerative colitis is more common in men than in women. In addition, men are more likely than women to be diagnosed with ulcerative colitis in their 50’s and 60’s (Figures 4 and 5). Geographic distribution: IBD is found mainly in developed countries, more commonly in urban areas, and more often in northern climates. However some of these disease patterns are gradually shifting. The highest Crohn’s disease incidence rate is reported in Approximately 1.6 million Americans currently have Crohn’s disease or ulcerative colitis. As many as 70,000 new cases of IBD are diagnosed in the United States each year.13 Crude Incidence Rate (per 100,000 person-years) Age Ranges Incidence of Ulcerative Colitis by Age Group and Gender in Olmsted County, Minnesota (Source: Loftus EV, Jr., Shivashankar R, Tremaine WJ, Harmsen WS, Zinsmeiseter AR. Updated Incidence and Prevalence of Crohn’s Disease and Ulcerative Colitis in Olmsted County, Minnesota (1970- 2011). ACG 2014 Annual Scientific Meeting. October 2014. 11 Canada while the highest ulcerative colitis incidence rates are reported in Denmark, Iceland, and the United States (Figure 6). Two major epidemiological studies were conducted in the United States, one in California and the other in Minnesota. Results for both studies are included in Figure 6. Racial and Ethnic Impacts IBD can affect people of any racial or ethnic group. At this time, there is limited data describing the incidence and prevalence of IBD among minority patients. One small study of IBD patients in California looked at interracial variations in disease characteristics. It included Caucasian, African American, Hispanic, and Asian subjects.14 For example, Asians were diagnosed with IBD at older ages than Caucasians and African Americans, and Hispanics were diagnosed at older ages than Caucasians. A higher proportion of Caucasians had a family history of IBD than African Americans or Asians. Other research shows that people of various ethnic groups who have immigrated to the United States from countries with low incidences of ulcerative colitis have higher rates of developing the disease once living in this country.15 This suggests that race and ethnicity alone are probably not the sole determining factors, and that unexplained environmental influences are at work. Crude Incidence Rate (per 100,000 person-years) Age Ranges Incidence of Crohn’s Disease by Age Group and Gender in Olmsted County, Minnesota. Source: Loftus EV, Jr., Shivashankar R, Tremaine WJ, Harmsen WS, Zinsmeiseter AR. Updated Incidence and Prevalence of Crohn’s Disease and Ulcerative Colitis in Olmsted Global variation in incidence rates for IBD. Source: Talley NJ, Abreu MT, Achkar JP, et al. American College of Gastroenterology IBD Task Force. Am J Gastroenterol. 2011;106(S1):S2-S25. 12 Racial Variations Data from the Multicenter African American IBD Study and the National Institute of Diabetes and Digestive and Kidney Diseases IBD Genetics Consortium suggest that there are differences in symptoms and location of disease among