If you live with type 1 diabetes, you’re at a higher risk of developing Crohn’s disease and other inflammatory bowel conditions (IBD). The reverse is also true.
But that’s not it. Recent discoveries have also found that chronic intestinal inflammation caused by inflammatory bowel diseases increases the risk of type 2 diabetes.
Crohn’s disease and IBDs in general are linked to diabetes in many ways. While a gene has recently been found to be involved in the coexistence of type 1 diabetes and Crohn's disease, the gut microbiome specific to people with IBDs is believed to impact glucose regulation and to be a marker for type 2 diabetes.
Let’s explore the relationship between these two chronic health conditions and shed some light on what we know so far.
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Type 1 Diabetes and Crohn’s Disease
We know that people with type 1 diabetes are at higher risk of having Crohn's disease. And people with Crohn's disease are at higher risk of having type 1 diabetes as well. While this relationship had long been misunderstood, recent studies on the genetics of autoimmune diseases have identified a common gene that might be a game-changer.
Two autoimmune diseases
Both type 1 diabetes and Crohn's disease are autoimmune diseases. Autoimmune disorders occur when the immune system mistakenly attacks the healthy cells of the body. Scientists have identified about 80 autoimmune diseases from which type 1 diabetes and Crohn’s disease are among the most common ones.
Type 1 diabetes is a condition where the immune system attacks the pancreas cells that are responsible for the production of insulin. This essential hormone helps move the sugar from the bloodstream to the cells for energy. When the pancreas makes too little or no insulin at all, the glucose stays in the bloodstream. High blood glucose levels over time can cause extremely serious complications.
Crohn’s disease is a type of inflammatory bowel disease (IBD) where the gastrointestinal tract gets chronically inflamed. The causes of this autoimmune disorder are still unknown, but the genetic influence is the most probable one.
Autoimmune diseases sometimes go hand in hand. About 25% of people with one autoimmune disease develop another one (polyautoimmunity). When you have three or more autoimmune diseases coexisting in the same patient, it’s called multiple autoimmune syndrome (MAS). Scientists believe this coexistence of several autoimmune diseases in the same person is caused by genetics as well as environmental factors.
While polyautoimmunity used to be the main theory to explain the link between Type 1 diabetes and Crohn’s disease, new studies have gone further and found a common gene.
Related article: 11 Great snacks for Crohn’s disease, IBD, and ulcerative colitis
One common gene
The PTPN2 gene is the one found to be involved in the coexistence of type 1 diabetes and Crohn’s disease in some patients.
Technically speaking, it’s the Protein Tyrosine Phosphatase Non-Receptor Type 2, a protein-coding gene involved in the regulation of the immune system. Interestingly, the PTPN2 gene was already known to be associated with numerous types of arthritis that may also be linked to diabetes.
Related article: What’s the link between diabetes and arthritis?
This major game-changing finding comes from a study conducted by the Wellcome Trust Case Control Consortium (WTCCC), a group of UK researchers. The Crohn’s disease and Type 1 diabetes relationship has been investigated by scientists from Cambridge University.
The identification of a common gene linking these two chronic conditions will help scientists understand better the relationship between the two. It will hopefully lead to new treatments or cures.
Related article: 10 tips for traveling with Crohn’s disease and IBD
Type 2 Diabetes and Inflammatory Bowel Diseases
Another link between diabetes and inflammatory bowel diseases lies in the relationship between type 2 diabetes and gut issues. Indeed, intestinal inflammation that occurs in Crohn's disease and other types of IBDs like ulcerative colitis may directly impact blood glucose levels.
Type 2 diabetes and gut issues
Type 2 diabetes is different from type 1 diabetes. This chronic blood glucose disorder isn’t caused by an autoimmune reaction but rather by external factors including age, weight, diet, and lifestyle.
In type 2 diabetes, the pancreas still produces insulin, but the body can’t use it properly. The results are the same: sugar stays stuck in the bloodstream instead of being delivered to cells for energy.
Studies have found that chronic inflammation of the intestinal tract that occurs in inflammatory bowel conditions may increase the risk of type 2 diabetes.
The gut is known to play a big part in the regulation of blood sugar. Research from the Technical University of Munich about the microbiome and diabetes found that daily variation of the gut microbiome does not happen in people with type 2 diabetes.
While the data clearly show that chronic bowel inflammation increases the risk for diabetes, the causes aren't completely understood yet and more research needs to be conducted on the subject.
To go a bit further, here are more studies on the topic you can refer to:
- Kumar, A., Teslova, T., Taub, E. et al.Comorbid Diabetes in Inflammatory Bowel Disease Predicts Adverse Disease-Related Outcomes and Infectious Complications. Dig Dis Sci 66, 2005–2013 (2021):
- Sang MM, Sun ZL, Wu TZ. Inflammatory bowel disease and diabetes: Is there a link between them? World J Diabetes 2022; 13(2): 126-128: https://www.wjgnet.com/1948-9358/full/v13/i2/126.htm
- Kang EA, Han K, Chun J, et al. Increased Risk of Diabetes in Inflammatory Bowel Disease Patients: A Nationwide Population-based Study in Korea. J Clin Med. 2019;8(3):343. Published 2019 Mar 11. doi:10.3390/jcm8030343: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6463263/
We hope this article has provided you with valuable information regarding the link between diabetes and inflammatory bowel diseases like Crohn’s and ulcerative colitis. While research is still at its early stage on the topic, we'll make sure to update this article regularly and provide you with the latest information.