There is growing evidence to suggest that coronavirus (Covid-19) might cause diabetes in some people, or making the condition worse for others. We take a look at the research so far and explain what scientists are doing to find answers.
Written by Faye Riley PhD, our Senior Research Communications Officer in our diabetes research team. This article is part of our series on the key things to know about coronavirus and diabetes research.
New cases of diabetes
Since early reports first came to light, we've seen results from larger studies looking at big groups of people who’ve recovered from coronavirus. One study tracked over 47,000 people in England who had been admitted to hospital because of coronavirus before August 2020. The researchers followed their health for up to seven months after they were discharged and found 5% of people went on to develop diabetes.
They also showed that people who’d been in hospital with coronavirus were 1.5 times more likely to be diagnosed with diabetes after they’d been discharged than people of the same age and background who hadn’t been in hospital with coronavirus.
Type 1 diabetes
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 could be an increase in inflammation inside the body caused by coronavirus. Inflammation can bring about insulin resistance, which means the body isn’t able to make proper use of the insulin it’s producing.
Another potential explanation could involve 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. When coronavirus ‘locks on’ to ACE-2, our pancreas cells might not be able to do their normal jobs of releasing insulin and processing glucose. It is possible that this could accelerate progression towards type 2 diabetes or bring already existing type 2 diabetes to light.
A new type of diabetes
Scientists are also looking into the possibility that coronavirus could be causing a new type of diabetes by directly damaging the pancreas.
A small study looking at pancreas cells grown in the lab and pancreas samples taken from people who sadly died from coronavirus found evidence that the virus invades and spreads in pancreas cells. The findings also raise the possibility that coronavirus infection might change how insulin-producing beta cells work.
Research into the biological processes that explain how and why coronavirus could cause diabetes is at an early stage and we need to be cautious about applying what scientists see in the lab and in donated pancreas samples to what’s happening in people infected with the virus. And we need more research to look at the types of diabetes we’re seeing in people who have had coronavirus to understand whether these are cases of type 1 and type 2 or something new altogether.
Temporary high blood sugars
It’s also possible that blood 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 drugs 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.
Can Covid-19 cause diabetes?
The evidence to suggest coronavirus could cause type 1, type 2 - or even a new type of diabetes - is growing but there’s still a lot we don’t know. We can’t yet be sure if coronavirus is directly causing any new cases of diabetes, or whether there are other factors that could explain the link.
Scientists are working hard to find answers and 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. On top of this, the government has pledged £18.5 million to fund research to better understand and treat the longer term effects of coronavirus. These projects could give us important insights into new cases of diabetes after coronavirus.
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 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.
Signs and symptoms of diabetes
During the coronavirus pandemic, it's still really important to see a healthcare professional if you notice any of these signs. They will be able to do a blood test to find out if you have diabetes. Watch this video to know the symptoms of diabetes.
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:
- whether people with diabetes are more likely to catch coronavirus
- the risk of needing to go to hospital or dying if people with diabetes get coronavirus
- how people with diabetes can reduce their risk of getting seriously ill from coronavirus
- why people with diabetes are more likely to get seriously ill from coronavirus.