About Type 1 Diabetes

An estimated 3 million Americans, or about 5 percent of all diagnosed diabetes cases are type 1, also called insulin-dependent diabetes mellitus (IDDM). Type 1 diabetes occurs when the insulin-producing cells in the body have been destroyed and the body is unable to produce any insulin at all, and is often developed in children. Everyone with type 1 diabetes has to be treated with insulin.

What Causes It?

Nobody knows for sure why these insulin-producing cells have been destroyed but the most likely cause is the body having an abnormal (autoimmune) reaction to the cells. This may be triggered by a virus or other infection. Because diabetes often develops after an infection, such as chicken pox, researchers theorize that after destroying the invaders, the immune system keeps attacking; but having no worthy targets turns on body tissue. The result is destruction of the cells that produce insulin in the pancreas. There is thought to be a genetic element to Type 1 diabetes and it is much more common in some parts of the world than others. But it has nothing to do with lifestyle or weight. It can develop at any age but  usually appears before the age of 40 and most commonly in late childhood.

Signs and Symptoms of Type 1 Diabetes

Type 1 diabetes often appears suddenly. Signs and symptoms can include:

  • nausea and vomiting
  • feeling edgy and having mood changes
  • weakness and tiredness
  • extreme weight loss
  • extreme thirst
  • extreme hunger
  • frequent urination and/or bed wetting in children
  • high levels of sugar in the blood and urine


Once type 1 diabetes has been diagnosed, it is vital to follow the physician’s treatment plan. The goal of the treatment plan is to keep the blood sugar level as close to normal as possible. It may include:

  • food to raise blood sugar levels
  • meal plans to regulate production of blood sugar
  • exercise
  • frequent blood sugar testing using a portable meter
  • urine testing for ketone levels

People with Type 1 diabetes no longer make insulin and must give themselves insulin every day. It can be injected, which involves use of a needle and syringe, or it can be given by an insulin pump or pen.

The amount of insulin needed depends on height, weight, age, food intake and activity level. Insulin doses must be balanced with meal times and activities and dosage levels can be affected by illness, stress or unexpected events.

Currently, there are over 30 types of insulin made by four companies in the United States. Allergic reactions to insulin are rare.

Diabetes Complications

There are three key complications of type 1 diabetes:

  • Hypoglycemia (Low blood sugar) – this is sometimes called an insulin reaction and happens when blood sugar drops too low
  • Hyperglycemia (high blood sugar) – this occurs when blood sugar is too high and is often a sign that diabetes is not well controlled
  • Diabetic Ketoacidosis – or diabetic coma, a very serious condition requiring immediate medical intervention

View the UF Health resource website