General causes
The diagnosis of Crohn’s disease represents a stroke of fate for many people. Naturally, many of those affected then ask themselves whether they could have done something about the development of the disease in advance. However, relatively little is known about the reasons for the development of Crohn’s disease – despite intensive research efforts, the cause has not yet been fully clarified.
There are, however, several theories, all of which contribute to the development of the disease. Together, they lead to a failure of the body’s own defense against bacteria in the intestines, which causes an inflammation as a reaction of the body to the seemingly overpowering germs. Crohn’s disease is therefore classified as an autoimmune disease.
One of the most important reasons for this failure of the immune system is probably a genetic predisposition. In twin studies, the hereditary part of the disease could be determined to be 60 – 70%, first-degree relatives of a person affected have a risk of the disease of about 10%. Several hereditary factors have been discovered in the human genome that contribute to the development of the disease, for example by producing less “endogenous antibiotic” due to the change in the genetic material, which normally protects the mucous membranes of the colon from bacteria.
This, together with many other, as yet unidentified, factors, leads to a disruption of the natural barrier between the intestinal wall and the intestinal contents, which is why actually harmless bacteria of the normal intestinal flora attack the intestinal wall and can thus trigger an inflammation. Furthermore, there is evidence that the bacterium “Mycobacterium avium subspecies paratuberculosis” can cause Crohn’s disease if the host has a certain gene mutation. The role of this pathogen is unclear, but studies have shown antibodies against it in more than 60% of Crohn’s disease patients.
Too much hygiene can also play a role in the development of the disease. This would explain the preferred occurrence of Crohn’s disease in countries with high standards of hygiene. In addition, studies have shown that smoking doubles the probability of developing Crohn’s disease. Psychological and nutritional causes have long been controversially discussed.
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