Exploring research: Can coronavirus cause diabetes, or make it worse?

Written by Faye Riley PhD, our Senior Research Communications Officer. This article is part of our series on the key things to know about coronavirus and diabetes research.

New cases of diabetes

At the start of the coronavirus pandemic, doctors started to raise concerns around new cases of both type 1 and type 2 diabetes in people who had caught the virus.

Type 1 diabetes

Since then, small studies have suggested that rates of new type 1 diabetes diagnoses in children are higher in 2020 compared to average rates in previous years.

The causes of type 1 diabetes are complex, and scientists think that there are a variety of environmental and genetic reasons that could explain why the condition develops.

Viruses could be one of these reasons, but the evidence around this is mixed and we just don’t know for sure yet. And as the virus that causes the Covid-19 infection is so new, there’s a lot we still need to learn about how it interacts with our immune system and its longer-term effects.

Type 2 diabetes

Cases of new type 2 diabetes diagnoses have also been reported in people who have had coronavirus. One possible reason for this could be to do with ACE-2. This is the protein on the surface of cells that coronavirus uses to enter and infect them.

ACE-2 is found in the pancreas and in other organs and tissues that play an important role in how our body processes glucose in our blood.

When coronavirus ‘locks on’ to ACE-2, our cells might not be able to do their normal job and help us release insulin and process glucose. It is possible that this could bring already existing type 2 diabetes to light, or perhaps even cause a new type of diabetes to develop. 

It’s also possible that blood glucose (sugar) levels in some people with coronavirus rise due to the stress the body is under when trying to fight the infection, or because of some of the treatments used to treat it.

This could play a role in new cases of diabetes developing. But we don’t yet know if, or when, high blood sugar levels in people with coronavirus return to normal after they have fully recovered.

Finding answers

The evidence to suggest coronavirus could trigger type 1, type 2 - or even a new type of diabetes - is growing, but we need to keep in mind that everything we know so far has come from only a handful of observational studies.

This is when researchers look at groups of people and collect information about them, such as who does and who doesn’t develop diabetes. But from these types of studies we can’t be sure if coronavirus is directly causing any new cases of diabetes, or whether there are other factors that could explain the link.

Although it still remains unclear what’s behind any apparent rise in cases, scientists are working hard to find answers.

An international group of top diabetes researchers are building a database of new cases of diabetes in people with coronavirus, called the CoviDiab registry. This will give them the information they need to carry out more thorough studies and discover more. 

Coronavirus and how type 2 diabetes progresses 

We’ve also heard reports that coronavirus could make type 2 diabetes progress more quickly in people who already have it. This could also be down to the impact of the virus on ACE-2, affecting how our body makes insulin and processes glucose. 

More research, including the PHOSP-COVID study, will help us to fully understand this better. The UK-wide study is following 10,000 people who were in hospital with coronavirus to monitor the long-term impact of the virus on their health. This study will include people with type 2 diabetes and will help us to understand how their condition has been affected. 

More things to know about coronavirus research

We know that you may have more questions about coronavirus and diabetes, so we've taken a look at the research to bring you the key things to know. Find out more about:

• the risk of needing to go to hospital or dying if people with diabetes get coronavirus