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COVID-19 infection may increase risk of type 1 diabetes, suggests nationwide study of 1.2 million children
National study calls into question COVID-diabetes link in young people
COVID-19 infection may increase risk of type 1 diabetes, suggests nationwide study of 1.2 million children
Nationwide study spanning first 2 years of the pandemic finds 0.13% of children and adolescents who contracted COVID-19 were diagnosed with type 1 diabetes a month or more after infection compared to 0.08% in children without a registered infection - a 63% relative increased risk
*note this work will feature in an embargoed press conference at the meeting, see details below*
*press release available in Spanish and Portuguese – see below*
Testing positive for SARS-CoV-2, the virus that causes COVID-19, is associated with an increased risk of new-onset type 1 diabetes in children and adolescents, according to a new research at this year’s European Association for the Study of Diabetes (EASD) Annual Meeting in Stockholm, Sweden (19-23 Sept). The study is by Hanne Løvdal Gulseth and Dr German Tapia, Norwegian Institute of Public Health, Oslo, Norway, and colleagues.
The study used national health registers to examine new onset type 1 diabetes diagnoses made in all youngsters aged under 18 in Norway (over 1.2 million individuals) over the course of 2 years, starting on March 1, 2020, comparing those who contracted COVID-19 with those who did not.
“Our nationwide study suggests a possible association between COVID-19 and new-onset type 1 diabetes”, says Dr Hanne Løvdal Gulseth, lead author and Research Director at the Norwegian Institute of Public Health. “However, the absolute risk of developing type 1 diabetes increased from 0.08% to 0.13%, and is still low. The vast majority of young people who get COVID-19 will not go on to develop type 1 diabetes but it is important that clinicians and parents are aware of the signs and symptoms of type 1 diabetes. Constant thirst, frequent urination, extreme fatigue and unexpected weight loss are tell-tale symptoms.”
It has long been suspected that type 1 diabetes, which is usually diagnosed in younger people and is associated with the failure of the pancreas to produce insulin, is a result of an over-responsive immune reaction, possible due to a viral infection, including respiratory viruses.
Several recent case reports have suggested a link between new onset type 1 diabetes and SARS-CoV-2 infection in adults. But evidence is more limited in children. A recent CDC report found that US children were 2.5 times more likely to be diagnosed with diabetes following a SARS-CoV-2 infection, but it pooled all types of diabetes together and did not account for other health conditions, medications that can increase blood sugar levels, race or ethnicity, obesity, and other social determinants of health that might influence a child’s risk of acquiring COVID-19 or diabetes [1].
In this nationwide study, Gulseth and colleagues linked individual-level data from national health registries for all children and adolescences in Norway (1,202,174 individuals). Data were obtained from the Norwegian preparedness register that is updated daily with individual-level data on PCR-confirmed SARS-CoV-2 infections, COVID-19 vaccinations and disease diagnoses from the primary and secondary health care service.
Children were followed from March 1st 2020 (the start of the pandemic) until diagnosis of type 1 diabetes, they turned 18 years old, death, or the end of the study (March 1st 2022), whichever occurred first.
The researchers examined the risk of young people developing new-onset type 1 diabetes within or after 30 days after PCR-confirmed SARS-CoV2 infection. They compared this group with children and adolescents in the general population who did not have a registered infection, as well as to a group of children who were tested but found to negative for the virus.
Over the 2 year study period, a total of 424,354 children tested positive for SARS-CoV-2 infection and 990 new-onset cases of type 1 diabetes were diagnosed among the 1.2 million children and adolescents included in the study.
After adjusting for age, sex, country of origin, geographical area and socio-economic factors, the analyses found that young people who contracted COVID-19 were around 60% more likely to develop type 1 diabetes 30 days or more after infection compared to those without a registered infection or who tested negative for the virus (see figure in full abstract).
“The exact reason for the increased risk of type 1 diabetes in young people after COVID-19 is not yet fully understood and requires longer-term follow-up and further research into whether the risk could be different in children who are infected with different variants”, says Gulseth.
She adds, “It’s possible that delays in seeking care because of the pandemic might explain some of the increases in new cases. However, several studies have shown that SARS-CoV-2 can attack the beta cells in the pancreas that produce insulin, which could lead to development of type 1 diabetes. It’s also possible that inflammation caused by the virus may lead to exacerbation of already existing autoimmunity.”
The authors acknowledge that the study was observational and does not prove cause and effect, and they cannot rule out the possibility that other unmeasured factors (e.g., underlying conditions) or missing data may have affected the results. They also note that they only included children who took a PCR test, not a lateral flow test or asymptomatic infections, in the analyses which may limit the conclusions that may be drawn.
Notes to editors:
[1] https://www.cdc.gov/mmwr/volumes/71/wr/mm7102e2.htm
The study received no funding.
The authors declare no conflicts of interest.
This press release is based on abstract 233 at The European Association for the Study of Diabetes (EASD). All accepted abstracts have been extensively peer reviewed by the congress selection committee. There is no full paper at this stage, but the authors are happy to answer your questions. As it is an oral presentation there is no poster.
For full abstract, click here
For full slides for press conference, click here
For press release in Spanish click here
For press release in Portuguese click here
Twitter (for when embargo lifts): @EASDnews #EASD2022
This work will be part of the EASD embargoed press on zoom taking place at 12.00H noon Stockholm time on Thursday 22 Sept. To join the Zoom event click the link below at this time.
https://us06web.zoom.us/j/87377579045?pwd=VTdobzV4MWFkSklwckMyb2FLOVg1Zz09
National study calls into question COVID-diabetes link in young people
Scottish study of over 1.8 million people aged under 35 suggests that increased short-term type 1 diabetes risk after contracting COVID-19 is unlikely to be due to the infection itself, and may be partly explained by increased testing around the time of diabetes diagnosis
*note this work will feature in an embargoed press conference at the meeting, see details below*
*press release available in Spanish and Portuguese – see below*
New research, being presented at this year’s European Association for the Study of Diabetes (EASD) Annual Meeting in Stockholm, Sweden (19-23 Sept), found that testing positive for SARS-CoV-2—the virus that causes COVID-19—is associated with an increased incidence of new-onset type 1 diabetes in people aged younger than 35 years, but this is restricted to the first month after infection, and is more likely explained by increased testing around the time of diabetes diagnosis and COVID-19 precipitating diabetes in those already developing it.
The study linked data on COVID-19 tests results to the Scottish diabetes register for the period between March 2020 and November 2021 [1], and tested whether this period of COVID-19 infection was associated with an increased risk of diabetes.
“Our findings call into question whether a direct association between COVID-19 and new-onset type 1 diabetes in adults and children exists”, says co-lead author Professor Helen Colhoun from Public Health Scotland and the University of Edinburgh, Scotland. “One recent report by researchers at the US Centers for Disease Control and Prevention (CDC), analysing two large insurance-claim databases of those under age 18, found that children with COVID-19 were 2.5 times as likely to be diagnosed with diabetes over a month after infection than those who were never infected. If replicated, this is going to create a large number of people with newly diagnosed diabetes and might also alter the risk–benefit balance for COVID-19 vaccination in young children. Importantly, we did not confirm that finding.”
In type 1 diabetes, which usually appears during childhood or adolescence, the immune system attacks insulin-producing cells, but it is not known why. One theory is that the immune system may be triggered by a viral infection and then accidentally also attacks insulin-producing cells. It has also been suggested that viral infections may increase the rate of progression of type 1 diabetes in people who still have normal blood sugar levels.
In this study, Colhoun and colleagues linked individual-level data on PCR-confirmed SARS-CoV-2 infections from the Electronic Communication of Surveillance Database, which captures all PCR tests for COVID-19 nationally, with precise dates of all new type 1 diabetes diagnoses from the national register in Scotland (that is updated daily).
During the study period a confirmatory PCR test was mandatory for all those with a positive lateral flow test.
The important aspect of this study is the exact dates of diabetes diagnosis were available, unlike in some earlier studies, ensuring that the time sequence of COVID-19 and type 1 diabetes could be established.
Between March 2020 and November 2021, a total of 365,080 children and adults had at least one detected SARS-CoV-2 infection, and 1,074 were diagnosed with type 1 diabetes.
The analysis found no association between SARS-CoV-2 infection and new-onset type 1 diabetes 30 days or more after infection, or in those aged younger than 16 years, contrary to several previously reported studies.
However, the researchers did find that children and adults with a first positive SARS-CoV-2 test were 2.5 times as likely to be diagnosed with diabetes within 30 days of infection compared to those who did not have a previous registered infection; this risk was more than three times higher in those younger than 16 years.
But the authors stress strong arguments against a causal effect of COVID-19 underlying this association.
Further analyses investigating the pattern of COVID-19 testing in relation to type 1 diabetes diagnosis found an increased frequency of SARS-CoV-2 testing in the days before and after diabetes presentation, for both negative and positive results. This suggests, says the authors, that the association may partly be explained by higher detection of infection at this time.
The authors also note that the average time from the onset of type 1 diabetes symptoms to diagnosis in those aged younger than 16 in England is around 25 days. So, it is likely that many of those who tested positive for COVID-19 within 30 days of a diabetes diagnosis already had type 1 diabetes at the time of infection.
The analyses also found no association between COVID-19 vaccination status and new-onset type 1 diabetes in adults (few children were vaccinated during the study period), providing further evidence against a causal effect of SARS-CoV-2 infection on the development of diabetes.
The researchers also looked at trends in type 1 diabetes incidence in Scottish children aged 0-14 years before and during the pandemic, finding that the incidence in 2020-2021 was around 20% higher than the 7-year average for 2015-2021.
However, they point out that based on estimates from England, the time course of the increase in diabetes incidence in those aged 0-14 years predated most of the cumulative incidence of SARS-CoV-2 infection in this age group (June 2021 onwards), suggesting a lack of causal association between COVID-19 and rates of diabetes [3].
“Our findings show that causes other than COVID-19 infection itself need to be considered in relation to the increased incidence of type 1 diabetes”, says co-lead author Professor Paul McKeigue from Public Health Scotland and the University of Edinburgh, Scotland. “We need to consider what has happened regarding the spread of viruses such as enteroviruses during the pandemic, and whether there are any other environmental factors, such as sunlight exposure and vitamin D levels, that might have altered during lockdown that might also be relevant.”
The authors point out that although their study was large, further analyses capturing the more recent part of the pandemic and more recent variants is needed. They also note that until mass testing was rolled out in the third quarter of 2020, most cases of COVID-19 in younger people were not detected, which could limit the conclusions that can be drawn.
For interviews with the report authors, please email Professor Helen Colhoun, Public Health Scotland and the University of Edinburgh, Scotland at helen.colhoun@ed.ac.uk
Alternative contact in the EASD Press Room: Tony Kirby T) + 44(0)7834 385827 E) tony@tonykirby.com
Notes to editors:
[1] In the REACT-SCOT case-control study, every incident case of COVID-19 in the Scottish population is matched with up to 10 controls matched for age, sex, and general practice.
[2] https://www.cdc.gov/mmwr/volumes/71/wr/mm7102e2.htm
[3] In England, the cumulative proportion of under 14s infected with SARS-CoV-2 was only about 8% up to the end of August 2020; it increased to 25% by the end of June 2021 and then increased more steeply to about 55% by the end of the study period (22 November 2021).This suggests that had the increase in incidence of type 1 diabetes been caused by COVID-19, most of the increase would have occurred after June 2021.
The authors have no conflicts of interest to declare. The research was partly funded by Diabetes UK.
This press release is based on abstract 160 at The European Association for the Study of Diabetes (EASD). All accepted abstracts have been extensively peer reviewed by the congress selection committee. The paper was recently published in the journal Diabetes Care, see below link to full paper and as such no abstract is included.
