Epidemiology
The incidence of Crohn's disease has been ascertained from population studies in Norway and the United States and is similar at 6 to 7.1:100,000. The Crohn's and Colitis Foundation of America cites this number as approx 149:100,000; NIH cites 28 to 199 per 100,000. Crohn's disease is more common in northern countries, and shows a higher preponderance in northern areas of the same country. The incidence of Crohn's disease is thought to be similar in Europe but lower in Asia and Africa. It also has a higher incidence in Ashkenazi Jews and smokers.
Crohn's disease has a bimodal distribution in incidence as a function of age: the disease tends to strike people in their teens and 20s, and people in their 50s through to their 70s, and ages in between due to not being diagnosed with Crohn's and being diagnosed instead with irritable bowel syndrome (IBS). It is rarely diagnosed in early childhood. It usually strikes females who are pediatric patients more severely than males. However, only slightly more women than men have Crohn's disease. Parents, siblings or children of people with Crohn's disease are 3 to 20 times more likely to develop the disease. Twin studies show a concordance of greater than 55% for Crohn's disease.
Read more about this topic: Crohn's Disease