Types of Diabetes

Reviewed by: HU Medical Review Board | Last reviewed: October 2020.

There are 3 main types of diabetes:1,2

These different types are all caused by high blood glucose (sugar) levels. When there is not enough insulin or the body stops responding to insulin, too much blood glucose stays in the blood. Insulin is a hormone that is created in the pancreas, and it works to move glucose from food into cells so it can be used for energy. Diabetes occurs when the body does not make enough insulin or cannot use the insulin it makes as well as it should. However, the reason this happens is different for each type of diabetes.3,4

Type 1 diabetes

In type 1 diabetes, the immune system attacks and destroys the cells in the pancreas that make insulin. Doctors and researchers do not know how to prevent this type of diabetes. About 5 to 10 percent of people who have diabetes have type 1. It is usually diagnosed in children and young adults, but it can appear at any age. People with type 1 diabetes must take insulin every day to stay alive.1,2

Type 2 diabetes

In type 2 diabetes, the body does not use insulin well, and eventually, it stops making insulin altogether. There are many risk factors for type 2 diabetes, including high blood pressure, being overweight, and age. Around 90 to 95 percent people with diabetes have type 2. This type of diabetes usually develops over many years and can be diagnosed at any age. There may not be any noticeable symptoms, so it is important to get your blood glucose levels tested if you are at risk.1,2

Gestational diabetes

This form of diabetes develops in some women when they are pregnant. Gestational diabetes usually goes away after the baby is born, but it does increase your risk for type 2 diabetes later in life. Gestational diabetes puts your baby at higher risk for health problems, including obesity as a child or teen and type 2 diabetes later in life. Doctors use the oral glucose tolerance test to screen women for gestational diabetes during pregnancy.1,2

Other types of diabetes

In addition to the 3 main types of diabetes, there are several other forms of the disease, including:2,5,6

  • Monogenic diabetes, which is an inherited form of diabetes
  • Latent autoimmune diabetes in adults (LADA), which has the characteristics of both type 1 and type 2 diabetes. This type is sometimes called 1.5 diabetes and can oftentimes be misdiagnosed as type 2 diabetes.
  • Cystic fibrosis-related diabetes, which is a unique type of diabetes that is common in people with cystic fibrosis
  • Prediabetes, which occurs when blood glucose levels are higher than normal levels, but they are not high enough to be diagnosed as type 2 diabetes. In the United States, more than 1 in 3 people have prediabetes. Prediabetes increases the risk for type 2 diabetes, heart disease, and stroke.

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