Many parts of the world saw record numbers of children diagnosed with type 1 diabetes during the pandemic – prompting speculation that COVID-19 might cause the disease to develop in children.
A new study from Germany speculates that COVID-19 did cause type 1 diabetes (T1D), but only indirectly. Perhaps it wasn’t the infection itself to blame, but the environmental changes due to lockdowns and other pandemic mitigation efforts?
COVID and Childhood Type 1 Diabetes Diagnoses
Since the summer of 2020, we have known that COVID-19 – a disease known to wreak havoc on blood sugar levels and the immune system – was causing new cases of diabetes among adults.
In January of 2022, the CDC published new evidence that COVID-19 also triggers new-onset diabetes in children. An analysis of insurance claim databases showed that children (<18 years) were 31 to 166 percent more likely to be diagnosed with diabetes 30 days or more after being diagnosed with COVID.
The data has rolled in from several other countries too, likewise suggesting that record numbers of children were diagnosed with type 1 diabetes during the pandemic.
The mechanism by which COVID might precipitate diabetes remains mysterious. The coronavirus has been theorized to attack the pancreatic Beta cells, which could trigger or accelerate the onset of diabetes. More serious cases also cause inflammation, insulin resistance, and acute stress hyperglycemia, effects that may be exacerbated by the use of steroids in hospitals. But children were far less likely to suffer severe illness, and in the CDC analysis, even children that were asymptomatic had an increased risk of new-onset diabetes.
In fact, we usually don’t know whether or not a child with new-onset type 1 diabetes even had COVID-19. A headline-making study of San Diego hospitals, for example, found that T1D diagnoses exploded in number, but there was no antibody testing done. (Only 2.1% had COVID-19 at the time of their T1D diagnoses).
Other work suggests that T1D rates increased during the pandemic even in the absence of COVID infection. A small study from Finland, for example, found that T1D diagnoses had increased by nearly 50% in 2020 from the previous year. When the doctors tested 33 of the newly diagnosed children for COVID antibodies, they found that not one of them had been previously infected.
As a result, it’s fair to ask whether COVID-19 infections caused the uptick in T1D diagnoses, or if there’s some alternative or additional explanation.
The latest issue of Diabetes Care includes a study of this topic using national data from Germany. The numbers showed that Germany, like several other nations, experienced a significant increase in childhood T1D diagnoses during the pandemic: 15 percent more than expected.
One thing that distinguishes Germany, though, is that it remained comparatively untouched by COVID-19 in the first months of the pandemic. Thanks to a robust public health response, and perhaps a little good luck, Germany largely avoided the large waves of infection during the spring and summer of 2020 that plagued many other countries, such as the United States. Seroprevalence studies confirm that very few German children caught COVID-19 during this period of time.
That makes the timing of the spike in type 1 diabetes diagnoses particularly interesting. The two months with the greatest increase in new T1D cases were June and July of 2020, soon after Germany began to roll back COVID-19 restrictions. And yet it would be months before the country experienced significant growth in COVID-19 infection numbers. And when infection numbers did rise, there seemed to be no proportional increase in T1D diagnoses.
(The summer 2020 increase in diagnoses, by the way, was almost certainly not due to parents delaying hospital visits during the height of spring 2020 lockdowns: T1D diagnoses were also elevated above expectations during March-May 2020.)
If very few German children actually caught COVID-19 in the spring and summer of 2020, why did childhood type 1 diabetes diagnoses spike to record levels? The authors of the study have a few ideas.
Theory One: Too Few Germs
This might sound funny – as many readers are no doubt aware, researchers believe that some viral infections can actually cause type 1 diabetes. Nevertheless, it’s possible that routine mild infections can protect against diabetes, too.
This is the theory known as the hygiene hypothesis, the idea that germ exposure is critical for the development of the immune system, especially in early childhood. Autoimmune disorders – including food allergies, asthma, eczema, and type 1 diabetes – are on the rise across the globe, especially in the developed world, possibly a consequence of our increasingly sanitary modern lifestyles. Although the hygiene hypothesis remains controversial, it has often been proposed as an explanation for the global rise of T1D.
Lockdowns in Germany and elsewhere closed schools, daycares, and even many playgrounds, while social distancing recommendations dramatically reduced extrafamilial interactions. The consequence may have been “a dramatic decrease in biodiversity in children,” depriving the immune system of the steady stream of germs that it needs to develop optimally. Could a less messy environment have caused some kids’ immune systems to malfunction?
Theory Two: Stress and Anxiety
It shouldn’t take much convincing that the pandemic brought with it a huge deal of stress, anxiety, and other mental anguish, much of it borne by smaller children barred from their usual activities and play opportunities. The early research confirms as much.
Less obvious is the degree to which psychological stressors can contribute to the development of type 1 diabetes. Several studies have identified mental health challenges as T1D risk factors. Chief among them was this 2015 Swedish study, which examined psychological questionnaires completed by 58 children before they had been diagnosed with diabetes. These survey responses showed that, in comparison to their thousands of peers, the children that would go on to develop T1D were much more likely to have experienced a “serious life event” – including death and severe illness in the family, parental divorce and re-marriage, and conflicts between adults at home.
For one thing, we know that stress hampers the immune system. The authors of the Swedish study further speculate that psychological stress leads to specific types of physiological stress – marked by elevated insulin demands, insulin resistance, and cortisol levels – that tax the pancreatic beta cells.
It’s possible, therefore, that increased stress related to COVID mitigation efforts helped to trigger some cases of type 1 diabetes in children.
Childhood cases of type 1 diabetes rose significantly in many countries during the pandemic. But a new study of German data suggests that, in at least one country, the rise in T1D diagnoses was unrelated to the prevalence of COVID-19 infections. Instead, the rise may have been an indirect consequence of lockdowns and social distancing recommendations intended to stem the spread of the novel coronavirus.
The speculation relayed in this article is by no means definitive, and much concerning the relationship between COVID and diabetes remains mysterious. Other studies – especially the January 2022 CDC analysis of American insurance claim data – show that the COVID-19 infection probably can directly precipitate type 1 diabetes. Perhaps the illness caused diabetes rates to skyrocket through both direct and indirect effects.