What causes type 1 diabetes?

Dr. Jeanne Morrison, PhD
Family Practitioner

Type 1 diabetes is caused by a disorder in the body's autoimmune system, or the body's ability to fight disease and infection. In diabetes, the autoimmune system attacks the cells in the pancreas (a large gland in the abdomen, near the liver) that produce insulin. Your body needs insulin to allow glucose, or sugar, to produce the energy required to live. As a result, people with diabetes must take insulin daily to restore what the body destroys.

No one knows the specific causes of type 1 diabetes, which affects approximately 5 to 10 percent of all those diagnosed with diabetes. It is not caused by diet or contagious disease. A predisposition to develop the disease does seem to run in families. Genetic, autoimmune and environmental factors are possible reasons why millions of people are affected by this chronic condition.

When you have type 1 diabetes, your pancreas no longer makes insulin. This happens when your immune system attacks and destroys your insulin-producing cells. This process can occur over a period of years before producing any symptoms at all. Scientists believe that genes, viruses or infections or other causes can trigger this immune response. Research is under way to find the exact causes of type 1 diabetes and how it might be prevented.

The causes of type 1 diabetes are complex and not completely understood. Researchers have identified several genes associated with the development of type 1 diabetes. The prevailing belief about the etiology, or cause, of type 1 diabetes is that while someone may have a genetic predisposition for developing the disease, it takes an environmental trigger or series of triggers (e.g., virus, toxin or drug) to set off the autoimmune process that destroys insulin-producing beta cells of the pancreas. A number of risk factors associated with type 1 diabetes have therefore been identified.

Intermountain Registered Dietitians
Nutrition & Dietetics Specialist

Type 1 diabetes—the type that's more common in young people—is the result of an autoimmune process. An autoimmune process is like a case of mistaken identity. Your body's immune system, which is responsible for protecting your body from invading illness, attacks your own healthy tissue by mistake. With type 1 diabetes, the autoimmune process attacks the pancreas, damaging it so it can't produce enough insulin.

The pancreas is an organ about the size of a child's fist. It's located behind your stomach. In type 1 diabetes, the body's immune system attacks the beta cells of the pancreas. These are the cells that make insulin.

The cause of type 1 diabetes is not currently known. Doctors and scientists continue to research this, but what we do know, is that the condition is not caused by anything someone affected did or did not do.

Gary Scheiner

Type-1 diabetes is an autoimmune disorder. The body's immune system inappropriately attacks the cells of the pancreas that secrete insulin, rendering them unable to control blood glucose levels. Defects such as these in the immune system are present at birth. A biological or environmental "trigger" is required to set the attack on the beta cells into motion. A variety of potential triggers have been identified, but we still do not understand the process well enough to prevent the onset of type-1 diabetes.

Mr. Eliot LeBow, CDE, LCSW

With type I diabetes you will find that there are both genetic and environmental risk factors.

Forty percent of people in the United States carries the gene that is related to diabetes from one parent. It's called the HLA genes (human leukocyte antigen). This risk is dependent on whether the person has duplicate HLA genes; one from each parent. This can lead to an increased risk of developing T1D.

Having diabetes in the family only increases one's chance of being diagnosed with diabetes by 10 to 15 percent. 

As far as other factors like environmental, the JDRF is presently running a longitudinal study following how environment impacts the chance of getting type I diabetes. 

At this point in time there are only causal relationships between the factors and actually getting type I diabetes. At this point we don't have anything concrete to go by for risk factors that can be controlled. 

My recommendation is that you live a healthy life style and just keep an eye out for these symptoms so you can get help asap if you develop T1 diabetes:

  • Extreme thirst
  • Frequent urination
  • Tired all the time
  • Sudden vision changes
  • Increased appetite
  • Sudden weight loss
  • Sweet or fruity odor on breath
  • Trouble breathing

If these symptoms occurs contact your doctor or your child's doctor immediately.

Continue Learning about Type 1 Diabetes Causes and Risk Factors

Which genes are responsible for the onset of type 1 diabetes?
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Researchers have identified several different genes that might make a person more likely to develop ...
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How do human leukocyte antigens (HLAs) affect type 1 diabetes?
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Human leukocyte antigens (HLAs) are proteins located on the surface of the cell that help the im...
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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.