Etiology of ulcerative colitis
The exact cause of ulcerative colitis is unknown. The most accepted theory about its etiology is that ulcerative colitis is an autoimmune disorder. Also, genetic and environmental factors play a role.
- Autoimmune theory: Normally, the immune system protects the body against the harmful invaders, and it achieves that using the white blood cells. The healthy immune system can identify the invaders and destroy them without attacking the body tissue. In ulcerative colitis, the immune system treats the lining of the large intestine, normal beneficial bacteria, and food as foreign invaders and attacks them. When the immune system attacks the normal large intestine, this causes inflammation and ulceration.
- Genetic factors: Some researchers found abnormal genes in people with ulcerative colitis. These abnormal genes suggest a link between genetics and ulcerative colitis. Also, the increased risk in some ethnic groups, such as Ashkenazi Jewish, implies a role for genetics. Also, the risk of ulcerative colitis is higher in those with positive family history. Abnormal genes may alter the immune response and direct it to attack the body tissues in the large intestine.
- Environmental factors: Ulcerative colitis is more common in urban areas, such as western Europe and America. Some environmental factors may increase the risk of ulcerative colitis, such as air pollution, some diets, stress, and some medications. Medications, such as antibiotics, contraceptive pills, and non-steroidal anti-inflammatory drugs, may increase the risk of getting ulcerative colitis. Also, foods rich in unsaturated fats may increase the risk. The previous factors may raise the risk of developing ulcerative colitis or worsening of the symptoms.
Unlike Crohn’s disease, smoking doesn’t represent a risk factor in ulcerative colitis. The incidence of ulcerative colitis is lower among smokers; 80% of the patients are nonsmokers.
