Colon removal linked to higher diabetes risk

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People who have had their colon removed have an increased risk of developing type 2 diabetes, according to a new study. The research suggests the organ may play a role in regulating blood sugar levels.

The study, which researchers based on data from more than 46,000 patients who have had part or all of their colon removed, may pave the way for new ways of preventing and treating the disease.

Model organism

“We know that the colon houses large numbers of gut bacteria and hormone-producing cells, but we still do not know which role they play in regulating the blood sugar level,” says Kristine Allin, head of section and staff doctor at the University of Copenhagen and the Center for Clinical Research and Prevention at Bispebjerg and Frederiksberg Hospitals.

“We hope our study will facilitate further research into the significance of the colon in blood sugar regulation and diabetes development,” Allin says.

Scientists compared the data to just under 700,000 comparable patients who in the same period had undergone surgery for something else than disease in the gastrointestinal tract. The study is an example of how researchers can use real human treatment in the healthcare system as a kind of model, says first author Anders Boeck Jensen from the Novo Nordisk Foundation Center for Protein Research.

“The surgical procedures these patients have undergone represent the trial, and the results are then determined from the many data held in the Danish registers. Researchers often use animal testing to identify a connection, before determining whether the results also apply to humans,” says coauthor and professor Søren Brunak from the Novo Nordisk Foundation Center for Protein Research.

“Here we are looking directly at surgery on humans, and we do not have to worry about whether the findings also apply to humans. The human as a ‘model organism’ is a concept that is gaining ground, ensuring that new patients benefit from experience and data collected through 20 years of treatment of previous patients,” Brunak says.

As reported in eLife, patients who had the entire or left side of the colon removed showed increased risk of developing type 2 diabetes in the 18 years following the operation compared to patients who had undergone surgery in different parts of the body.

Patients who had the right or middle horizontal part of the colon removed showed no increased risk of developing diabetes, suggesting that the left side of the colon plays a role in regulating the body’s blood sugar level.

3x higher BMI

The colon is full of gut bacteria and microbes, and some other studies indicate that a changed composition of these microbes—like when patients have part of the colon removed in surgery—may play a role in the development of various diseases, aside from infections.

“The greater majority of the body’s microbes are found in the colon, so it is relevant to look at what happens after the colon or part of it is removed,” says coauthor Thorkild I.A. Sørensen, professor in the public health department at the University of Copenhagen and Novo Nordisk Foundation Center for Basic Metabolic Research.

“In a previous study we saw no significant connection with the risk of developing cardiovascular diseases. We were therefore rather surprised to see so relatively massive an increase in the risk of developing type 2 diabetes. In fact, the increased risk corresponds to the effect of having three times as high a BMI,” Sørensen says.

The Novo Nordisk Foundation, the Danish Diabetes Association, and the EU’s research and innovation program Horizon 2020 funded the work.

Source: University of Copenhagen