People who have Crohn’s disease or ulcerative colitis have an increased risk of later developing type 2 diabetes.
People with chronic inflammatory bowel disease, such as Crohn’s disease and ulcerative colitis, have gut inflammation that remits and relapses throughout their life.
A Danish study now shows that these people also have an increased risk of developing another lifelong disease: type 2 diabetes.
Many people with inflammatory bowel disease therefore have to cope with not just one but two chronic diseases.
“It was previously thought that people with inflammatory bowel disease did not have a high risk of developing type 2 diabetes because they were rarely overweight. But other factors influence the risk of developing type 2 diabetes, and some is based on the composition of gut bacteria and the hormones secreted by the gut. Our study indicates that people with inflammatory bowel disease have substantial disturbances of their gut significantly increasing their risk of developing type 2 diabetes,” explains a researcher behind the study, Kristine Allin, Staff specialist and research leader, Department of Epidemiology Research, Statens Serum Institut, Copenhagen and Associate Professor, Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen.
The research has been published in Clinical Gastroenterology and Hepatology.
Data from more than 6 million people
Kristine Allin and her colleagues examined data from Denmark’s comprehensive registries, including the Danish National Patient Registry and the Danish National Prescription Registry, to determine the incidence of type 2 diabetes among people with inflammatory bowel disease compared with the background population.
The registries date back to 1977, and the researchers therefore had access to data on more than 6 million people.
The researchers linked the diagnostic codes in the registries for Crohn’s disease, ulcerative colitis and type 2 diabetes and found that 3,436 people with inflammatory bowel disease developed type 2 diabetes from 1977 to 2014.
The incidence of type 2 diabetes among people with inflammatory bowel disease was 50% higher than in the background population.
“A 50% increase in incidence may not sound like much, but type 2 diabetes is very common, so this finding is important,” says Kristine Allin.
The study also shows that the risk of developing type 2 diabetes was highest the first year after a person was diagnosed with inflammatory bowel disease, but remained increased for 20 years or more.
In addition, both major types of inflammatory bowel disease were associated with this increased risk.
“People with Crohn’s disease and ulcerative colitis had roughly the same risk. The risk of developing type 2 diabetes might have been increased for these people because they are often treated with corticosteroids, but we controlled for this, and the association remained,” explains Kristine Allin.
Type 2 diabetes increasingly common
Kristine Allin and her colleagues are now investigating the underlying causes of the link between inflammatory bowel disease and type 2 diabetes.
They are investigating whether the surgical removal of part of the small intestine, which is one remedy for Crohn’s disease, may be the cause. Another possibility is the drugs used to treat inflammatory bowel disease.
Finally, another cause could be that intestinal disease can disturb gut microbiota, distorting the normal functioning of the gut and thus also glucose metabolism.
However, the researchers surprisingly found that several factors seem to be involved and that the cause may not be simple.
“We found that people with inflammatory bowel disease have a higher risk of developing type 2 diabetes in recent years than in earlier years. This surprises us since we operate less today than before but perhaps treat more aggressively with new biological drugs. We would actually expect these drugs to improve glucose metabolism and to reduce the risk of developing type 2 diabetes, but the numbers tell a different story, and we are investigating this,” says Kristine Allin.
Take care of your health
Kristine Allin says that the study very clearly indicates that people with inflammatory bowel disease should not believe that they have a lower risk of developing type 2 diabetes – on the contrary.
This means that they, like the rest of the population, should try to eat healthy food and exercise to counteract the risk of developing type 2 diabetes and other lifestyle-related diseases.
They should also focus on not becoming overweight.
“People with inflammatory bowel disease have an increased risk of developing type 2 diabetes, and relieving the pressure on the body by living healthily is important,” concludes Kristine Allin.