Last edited 06/2019 and last reviewed 05/2022

  • frequently seen in industrialized countries (in Europe and North America) and is rare in underdeveloped countries (1)

  • even in countries with several ethnic groups, the risk of developing the disease was lower in those with a less westernised way of life (1)

  • Crohn's & Colitis UK estimate there are at least 115,000 people in the UK with Crohn's disease (3)

  • annual incidence in the UK is approximately 5/100,000. A GP in UK can expect a new case of Crohn’s disease every seven years (4)

  • women more affected than men

  • most commonly affected age group is between 15 and 30 years, although it may be seen in people of any age (4). There is also a second peak in the elderly.
  • at the time of diagnosis
    • 15% of people are older than 60 years
    • 20-30% are younger than 20 years (4)

  • familial clustering and involves ulcerative colitis as well as Crohn's disease

  • more common in smokers than non-smokers (4:1)

  • most common site of disease is the terminal ileum