What Causes Type 1 Diabetes?

Tahirah Chichester, MPH, Simon Spichak
·5 min read

Medically reviewed by Kelly Wood, MD

Type 1 diabetes is a chronic (long-lasting) condition in which the pancreas makes very little or no insulin. The pancreas is an organ that produces insulin, a hormone that helps the body make energy from glucose. When a person develops type 1 diabetes, the body’s immune system attacks the cells in the pancreas that makes insulin.

When this happens, the pancreas stops creating insulin. Without insulin, the amount of glucose in the blood builds and the levels become too high. Over time, high blood glucose levels can lead to health complications, causing damage to the kidneys, eyes, heart, and nerves.

Type 1 diabetes is considered an autoimmune disorder. The exact cause of type 1 diabetes is unknown, but researchers suspect a combination of genetic and environmental factors may trigger the condition.

Risk Factors

The immune system helps our bodies fight bacteria, viruses, and other harmful substances. With type 1 diabetes, the immune system attacks and destroys healthy beta cells in the pancreas. This is known as an autoimmune response.

Beta cells produce insulin, a hormone that helps the body turn glucose (a type of sugar) into energy. When the immune system destroys beta cells, they are unable to make insulin. This causes the amount of glucose in the blood (or, blood sugar) to rise to above-normal levels.

Researchers do not know why the immune system attacks beta cells. They have found that a combination of genetics and environmental factors may increase your risk of developing type 1 diabetes.

Related:Symptoms of High Blood Sugar

Genetics

Researchers have studied a group of genes called the human leukocyte antigen (HLA) complex and how they relate to type 1 diabetes. The HLA complex includes the HLA-DQA1, HLA-DQB1, and HLA-DRB1 genes. These genes help the immune system tell the difference between the body’s own proteins or proteins made by viruses or bacteria.

A single HLA gene can have many variations. However, a specific combination of variations (known as a haplotype) in the HLA-DQA1, HLA-DQB1, and HLA-DRB1 genes may change how the immune system works.

HLA haplotypes may increase the risk of the immune system’s attack on healthy beta cells. This, in turn, can increase a person’s risk of developing type 1 diabetes.

People with HLA gene variations do not always lead to type 1 diabetes. While some HLA variations may increase the genetic risk for type 1 diabetes, other variations can protect against the condition.

Environmental

Researchers suspect that viral infections may also play a role in the development of type 1 diabetes. When combined with genetic factors, viral infections may trigger an autoimmune response.

Evidence has been strongest for enterovirus (EV). One study showed EV infection was 10 times greater at the onset of type 1 diabetes compared to people without EV infection. Other viruses that have been studied include but are not limited to:

  • Rotavirus: A contagious virus that causes diarrhea

  • Cytomegalovirus: A common virus that sits dormant in your body until it's triggered, usually by a weakened immune system

  • Epstein-Barr virus: A common herpes simplex virus that spreads through bodily fluids like saliva

  • Mumps: Caused by a contagious virus that spreads through bodily fluids, usually causing pain and inflammation in the salivary glands

  • Rubella: A contagious virus that causes a distinctive red rash

The timing of viral infections is important to consider, especially during pregnancy to the first year of life. In one study, viral infections during pregnancy resulted in children who were two times more likely to develop type 1 diabetes.





Mumps and rubella can be prevented with the MMR vaccine, which stands for measles, mumps, and rubella vaccine. This vaccine is given in two doses early in life: One between 12-15 months of age and one between 4-6 years of age.




Is Type 1 Diabetes Hereditary?

If you are living with type 1 diabetes, you may wonder if you inherited the condition from your parents. You may also wonder if you can pass the condition on to your children if you wish to start a family.

Like other autoimmune diseases, type 1 diabetes tends to run in families. You are more likely to develop type 1 diabetes if you have a parent or sibling with the condition. People who do not have a family history can also develop type 1 diabetes.

In either case, people who develop type 1 diabetes have one or more genes that raise their risk for the condition. However, having those genes is not enough to directly cause type 1 diabetes. People do not inherit the condition itself. Instead, they inherit genetic factors which, in turn, increase the risk of developing type 1 diabetes.

Type 1 diabetes is a complex autoimmune condition. Combined genetic and environmental risk factors may trigger the autoimmune response that leads to type 1 diabetes.

Who Gets Type 1 Diabetes?

Anyone can develop type 1 diabetes. Some people are more likely to develop the condition than others. The following risk factors may increase your likelihood of type 1 diabetes:

  • Age: Although the condition can happen at any age, type 1 diabetes is often first diagnosed in children, teens, and young adults. It is the most common form of diabetes in children.

  • Ethnicity: In the United States, non-Hispanic white people are more likely to develop type 1 diabetes than African Americans or Latino/Hispanic Americans.

  • Geography: The number of new type 1 diabetes diagnoses is higher in countries further away from the Earth’s equator. Type 1 diabetes occurs less frequently in Asia and South America when compared to the United States, Canada, Europe, and Canada. During the last 20 years, however, the number of new type 1 diabetes diagnoses has been increasing worldwide.

Related:Can You Prevent Type 1 Diabetes?

A Quick Review

Type 1 diabetes happens when the body's immune system attacks and destroys the insulin-producing beta cells in the pancreas. Without insulin, the body is unable to take in glucose from the blood to make energy. This causes blood glucose levels to increase above normal levels.

While the underlying cause is unknown, researchers suspect genetic and environmental risks could lead to the development of type 1 diabetes. Other factors, such as age and geography, also raise your chances of developing the condition.

For more Health news, make sure to sign up for our newsletter!

Read the original article on Health.