The exact causes of inflammatory bowel disease (IBD) are difficult to prove, but there are some recognized risk factors which we've listed below based on information from health.com: 1. Geography People who live in developed western countries are more likely to have inflammatory bowel disease. This could be down to lifestyle choices such as smoking, drinking, a diet of processed foods, or the effects of pollution. However, less-developed countries, particularly in Asia, are experiencing a rise in the number of cases of IBD. This could also be due to the increase of processed foods in worldwide diets or an increase in environmental pollution. 2. Age Ulcerative colitis and Crohn's disease are more likely to be diagnosed in teenagers and young adults, but older adults can develop it later in life. Younger patients tend to have a more aggressive form of the condition. Younger patients are thought to have the disease due to genetic factors whereas older people are more likely to be affected by environmental factors. 3. Smoking Smoking affects IBDs in different ways. People who smoke are more at risk of developing Crohn's disease and smoking exacerbates the symptoms, whereas ex-smokers are more susceptible to ulcerative colitis. Watch as Rebecca describes what it’s like to live with an ostomy bag. 4. Appendicitis Young people who have had their appendix removed due to appendicitis are at a lower risk of developing ulcerative colitis. The reason behind this is not fully understood but it's thought it could be due to a change in the way the immune system functions.