Crohn’s disease (CD) is a chronic disease that affects the gastrointestinal tract, mainly the small and large intestines (NIDDK), and can be classified as an inflammatory bowel disease (IBD) (Molodecky). Although the most common areas of inflammation are the intestines, the disease can occur anywhere along the GI tract, from the mouth to the anus. While IBDs have been reported since the early 18th century (Mulder), the first report of Crohn’s disease was published in 1932, written by Burrill B. Crohn and two colleagues (Aufses). Their study was conducted at Mount Sinai Hospital in New York, and included 14 patients, mainly young adults. Crohn described the disease as one of inflammation in the terminal ilium of the small intestine. Since then, much research has been performed to better understand this disease, and how to prevent and treat the causes and symptoms.
While the exact cause of CD is not known, it is thought to be a combination of genetic, environmental, and bacterial factors (Stefanelli). Approximately half of the risk of developing the diseases is associated with genetic factors, yet they don’t appear to play a role until acted upon by environmental factors (Baumgart) (Stefanelli). Family aggregation has been studied to identify genetic components of the disease, mainly in twins, or siblings (Spehlmann). Over 70 different loci on chromosomes have been identified as having susceptibility to Crohn’s disease (Cho). Even with these studies, more detailed studies and information is needed to pinpoint exactly where in the genome problems are arising (Baumgart).
Researchers differ on how big a role demographics and environmental factors play on the activation, or development, of the disease (Baumgart) (Marks) (Stefanelli). Studies differ about gender predominance; some report that there is a female predominance for developing Crohn’s disease, while others show that both genders are affected equally (Hovde) (NIDDK). Development of the disease usually occurs during young adulthood, but can affect a person of any age (NIDDK). Even though the disease was first reported in 1932, the latter half of the 20th century saw an emergence of the disease. Reasons for this are still unknown, but may be due to genetics, geography, and industrialization (Mulder). There is a prevalence of the disease in developed countries. Not only do they report more diagnosis of CD, but also immigrants who have migrated from developing countries where there is low incidences of the disease, have shown a susceptibility to the disease. This can be contributed to industrialization, or modernization, of these countries; more processed food in the diets, exposure smog and air pollution, better sanitation and hygiene, and more sedentary lifestyles (Baumgart). The geographic location of a person can affect what viruses and bacteria that person comes in contact with during their life. This can be a hindrance, or benefit, to the immune system.
The states of the immune system and bacterial flora of the gut have been associated with the development of CD. There are, again, some discrepancies as to whether or not this disease can be classified as an autoimmune disease. What most will agree on is that there was an immunodeficiency to that lead to the development of Crohn’s disease (Marks) (Yamamoto-Furusho). Crohn’s disease is also linked to an imbalance in the bacterial colonies of the intestines. Viral and bacterial gastroenteritis can cause this imbalance to happen. This imbalance can also affect the immune system and how it responds to signals of the body (Baumgart).
With the steady prevalence and emergence of Crohn’s disease, it is important that the studying and understanding of the disease also increase. Although studies are being conducted, there is still little known about the development of the disease, leading to many controversies. Further research and understanding will only continue to allow medical professional to provide care and maintenance to their patients, and can even allow for earlier detection and/or prevention of this disease.