What Causes Diabetes?

Diabetes is a long-term (chronic) disease in which the body cannot regulate the amount of sugar in the blood.

Causes

Insulin is a hormone produced by the pancreas to control blood sugar. Diabetes can be caused by too little insulin, resistance to insulin, or both.

To understand diabetes, it is important to first understand the normal process by which food is broken down and used by the body for energy. Several things happen when food is digested and absorbed:

• A sugar called glucose enters the bloodstream. Glucose is a source of fuel for the body.
• An organ called the pancreas makes insulin. The role of insulin is to move glucose from the bloodstream into muscle, fat, and other cells, where it can be stored or used as fuel. 

People with diabetes have high blood sugar because their body cannot move sugar from the blood into muscle and fat cells to be burned or stored for energy, and/or because their liver makes too much glucose and releases it into the blood. This is because either:

• Their pancreas does not make enough insulin.
• Their cells do not respond to insulin normally.
• Both of the above.

There are two major types of diabetes. The causes and risk factors are different for each type:

• Type 1 diabetes is less common. It can occur at any age, but it is most often diagnosed in children, teens, or young adults. In this disease, the body makes little or no insulin. This is because the pancreas cells that make insulin stop working. Daily injections of insulin are needed. The exact cause of the failure to make enough insulin is unknown.
• Type 2 diabetes is more common. It most often occurs in adulthood, but because of high obesity rates, children and teens are now being diagnosed with this disease. Some people with type 2 diabetes do not know they have it. With type 2 diabetes, the body is resistant to insulin and doesn't use insulin as well as it should. Not all people with type 2 diabetes are overweight or obese.

References: MedlinePlus [Internet]. Bethesda (MD): National Library of Medicine (US).