New findings: COVID not likely to trigger islet autoimmunity in Australian children
The COVID pandemic saw an increase in new cases of type 1 diabetes (T1D) around the world. But researchers haven’t been able to determine whether COVID infection directly causes T1D or if other factors during the pandemic led to this increase. A JDRF-funded study has just published its results showing that in an Australian group of children, COVID infections were not linked to the early stages of T1D development known as islet autoimmunity.
Type 1 diabetes (T1D) is an autoimmune condition in which the beta cells of the pancreas, which normally produce insulin, are mistakenly attacked by the immune system.
Researchers think that in people who are genetically predisposed to T1D, something in the environment ‘triggers’ the start of the immune attack. The exact triggers remain unclear but there is evidence suggesting that certain viruses could contribute to the development of T1D.
With the COVID pandemic coinciding with an increase in new T1D cases around the world, researchers have been questioning whether the virus that causes COVID is one of these viral triggers. However, evidence from research around the world has been mixed. For example, some studies have shown that COVID increases the risk of islet autoimmunity – a sign that the immune system has started attacking the beta cells of the body. Other studies have shown this is not the case. And yet others have suggested that a COVID infection may speed up the progression of early-stages T1D to a clinical diagnosis. (Read more about autoimmunity and the stages of T1D.)
That’s why JDRF-funded researchers sought to find out if there was a link between a prior COVID infection and the development of islet autoimmunity in an Australian setting. The findings have just been published in leading medical journal, JAMA Pediatrics.
Australian researchers focus on environmental factors that could start the development of T1D
The researchers were part of the Environmental Determinants of Iselt Autoimmunity (ENDIA) study. The ENDIA study has been supported by JDRF and The Leona M. and Harry B. Helmsley Charitable Trust (Helmsley) for over a decade.
ENDIA is the world’s first study to track 1,500 children, starting from pregnancy, who have a family member with T1D. The goal is to find out what environmental factors might trigger the immune system to attack the pancreas as evidenced by islet autoimmunity.
To do this, the study is collecting samples from the children and their families to learn about things like their diet, exposure to viruses and illness, and gut health. Over 165,000 samples have already been obtained, including nasal swabs, urine, stool and breastmilk samples.
The main goal of ENDIA is to find out what causes and triggers T1D, so we can develop ways to prevent it from happening in the first place.
Does COVID increase the chance of developing T1D?
The research featured in JAMA Pediatrics aimed to see if a past COVID infection in nearly 1,300 of the ENDIA children was linked with a higher risk of developing islet autoimmunity. Islet autoimmunity can be tested by a simple blood test
To do this, the researchers collected blood samples from the children in the ENDIA study to look at signs of autoimmunity, as well as past COVID infections. They also asked parents if their children had previously had a confirmed COVID infection.
The study found two important things:
- The rates of islet autoimmunity in the ENDIA children remained the same during and after the COVID pandemic. In other words, the ENDIA group didn’t see an increase in islet autoimmunity as COVID cases grew in the community.
- When researchers split the ENDIA children into two groups – those with and without a past COVID infection – the rates of islet autoimmunity were the same between the groups.
Both these findings suggest that there is likely no link between having COVID and developing islet autoimmunity in Australian children. That is, becoming infected with COVID doesn’t increase your risk of going on to develop T1D.
What do these findings mean and what’s next?
The findings from the ENDIA study team suggest that, at least in the group of Australian children monitored, the virus that causes COVID is not likely to be an environmental factor triggering the onset of T1D.
This contrasts to other viruses, such as enteroviruses which have been associated with T1D development.
The differences seen in this study with past studies around the world with respect to the links between COVID and T1D could be due to:
- differences in how the studies were set up
- the ethnicities, genetics and age group of participants, or
- how COVID spread in different parts of the world, including different “lock-down” policies in countries.
For example, regarding the different genetics of participants, studies in the northern hemisphere focused on children with specific genetic markers linked to T1D risk, while the ENDIA study looks at children who have a close family member with T1D.
The ENDIA study team will continue working to uncover other environmental factors, including other viruses, which could be triggering and driving T1D in Australian children. Identifying these triggers is critical to developing preventative strategies such as vaccines that could delay or even prevent the people from getting T1D in the first place.
Dr Ki Wook Kim, who led the study, says:
Global research has explored whether SARS-CoV-2 (COVID) increases the risk of type 1 diabetes, but the results have been mixed.
We conducted the only southern hemisphere study to see if a past COVID infection raises the risk of islet autoimmunity in Australian children. Islet autoimmunity signals the first sign of self-damage of the pancreas, a hallmark of T1D.
While studies in Europe and the US have had conflicting findings, our ENDIA study of 1,500 Australian children found no link between COVID and increased islet autoimmunity risk.
More research is needed to understand the rise in T1D diagnoses since the pandemic. We are now investigating the role of gut-infecting enteroviruses as a potential trigger for islet autoimmunity. If we can identify what triggers the development of islet autoimmunity, well before the development of type 1 diabetes, we can then put in place early intervention strategies, like vaccination, which can delay or even prevent people from getting the condition altogether.
– Dr Ki Wook Kim
Dr Ki Wook Kim, joint senior author of JAMA Pediatrics publication and investigator in the ENDIA Study
Dr Ki Wook Kim worked with a number of other ENDIA scientists on this research, including the paper’s first author, Dr Greg Walker.
Dr Greg Walker, first author of the JAMA Pediatrics publication and based at UNSW Sydney
