At What Age Is IBD Most Common?:
IBD is often considered a disease of adolescents and young adults because it is most commonly first diagnosed in people between the ages of 15 and 25 years (at least one source indicates peak incidence to be between 15 to 35 years). Of the estimated 1.4 million people in the United States who have IBD, 10% are children. At about age 50 there is another increase in the diagnosis of IBD.
Is IBD More Common In Men Or Women?:
IBD appears to affect both genders equally.
In What Geographic Areas Is IBD More Prevalent?:
IBD is more common in:
- Developed countries
- Urban areas
- Northern climates
How Many People Have IBD?:
It is widely estimated that between 1 and 1.4 million people in the United States have IBD. (Some experts indicate that this number may be an overestimate.) In Europe, the number of people with IBD is estimated to be 2.2 million.
In the United States, the prevalence of IBD is:
- Ulcerative colitis: 100 to 200 people per 100,000 people
- Crohn's disease: 30 to 100 people per 1000,000 people
What Ethnicities Have A Higher Risk Of IBD?:
- Ashkenazi Jews are more likely to develop IBD.
- IBD is more common in white people, but the incidence in African Americans is increasing.
Do Environmental Factors Affect The Risk Of Developing IBD?:
Two factors, appendectomy and a history of cigarette smoking, have been shown to have an affect on the development of IBD. The results of 13 studies conducted between 1987 and 1999 suggest that removal of the appendix could lessen the risk of developing ulcerative colitis by up to 69 percent.
What Is The Risk Of Inheriting IBD?:
- There seems to be a stronger risk of inheriting Crohn's disease than ulcerative colitis, especially in families of Jewish descent.
- Children who have one parent with Crohn's disease have a 7 to 9% lifetime risk of developing the condition and a 10% risk of developing some form of IBD.
- Children of two parents who have IBD have a 35% risk of developing some form of IBD.
- Approximately 20% of people with IBD have a family member with IBD.
- The risk of IBD for persons who have a family member who has IBD is 10 times higher than for persons in the general population.
- The risk of IBD for persons who have a sibling with IBD is 30 times higher than for persons in the general population.
Other factors, such as diet, use of oral contraceptives, and infections are being studied, but their role is still unclear.
The Crohns and Colitis Foundation of America. Available at: http://www.ccfa.org/about/press/epidemiologyfacts. Last accessed January 6, 2005.
Loftus EV Jr. Clinical epidemiology of inflammatory bowel disease: Incidence, prevalence, and environmental influences. Gastroenterology. 2004 May;126(6):1504-17.
Peeters M, Nevens H, Baert F, et al. Familial aggregation in Crohn's disease: Increased age, adjusted risk and concordance in clinical characteristics. Gastroenterology. 1996;111:597-603.