Type 1 diabetes: origin and causes

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Type 1 diabetes is an autoimmune disease, meaning that it results from a problem with the body’s immune system. Experts are now pretty familiar with the natural course of the disease but the factors that trigger its development are still the subject of debate.

Is it a disease of the pancreas?

Type 1 diabetes, also known as insulin-dependent diabetes, is an autoimmune disease. It originates in the immune system: the antibodies that are meant to fight infections change into autoantibodies and attack some of the body’s own cells. In Type 1 diabetes, these antibodies target the pancreas and, more specifically, insulin-producing cells called beta cells.

Thus, detecting these autoantibodies in a patient’s blood is very useful when it comes to making a diagnosis of Type 1 diabetes.

It is now known that each individual has a genetically determined amount of beta cells when they are born. It is estimated that 80 to 90% of these pancreatic beta cells need to be destroyed before Type 1 diabetes develops. Based on this understanding of the natural course of the disease, a number of hypotheses have been put forward to explain why it develops, these not necessarily being mutually exclusive.

Does genetic predisposition play a role?

Type 1 diabetes is not, strictly speaking, a genetic disease (unlike Type 2 diabetes). However, we now know that genetic predisposition plays a role. The genetic component of Type 1 diabetes is backed up by studies conducted in the families of people living with diabetes: people with a brother or sister with Type 1 diabetes are more likely to have the condition themselves than the population as a whole. This extra risk is not directly linked to the presence of “genes involved in Type 1 diabetes” among siblings; it is more about the influence of genes involved in immune system regulation.

This shared family predisposition therefore means that the family members of someone with type 1 diabetes (be they brothers, sisters or children), have a higher likelihood than the population as a whole of developing type 1 diabetes or other autoimmune conditions, such as thyroid or celiac disease.

Could a virus be a factor in the development of Type 1 diabetes?

But genetics aren’t everything and other hypotheses have also been put forward. The first is the possibility of a viral link, the focus being on enteroviruses, which can cause infections from a very young age, even while still in the womb. Viral infections are also thought to play a role in other autoimmune conditions. But we still don’t know if the infection actually causes the autoimmunity or if it is simply a triggering factor.

Related to this viral hypothesis, vaccines – accused of all kinds of evils – have also been held up as suspects in Type 1 diabetes. However, the various studies published to date on the subject tend to exonerate them.

Are our kids too clean?

Another hypothesis that’s being taken seriously by scientists is the hygiene theory. According to this, excessive hygiene means that our children are exposed to fewer infections, making their under-used immune systems “hyper-reactive” and thereby encouraging a rise in autoimmune conditions, including Type 1 diabetes. Early exposure to infections is believed to help bolster the immune system and regulate its response to attacks. However, current scientific data do not yet provide sufficient evidence to support the hygiene theory as a main cause of Type 1 diabetes.

What about stress?

We sometimes hear about cases of diabetes “caused by emotional stress” or psychological trauma. It would actually be more prudent here to talk about triggering factors accelerating the manifestation of the disease and the development of symptoms. While it’s true thata period of intense stress or an infection may coincide with a diagnosis of diabetes, in all likelihood, the condition was already present.

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