A NIDDK Overview of Diabetes
Almost every one of us knows someone who has diabetes. An estimated 16 million people in the United States have diabetes mellitus -- a serious, lifelong condition. About half of these people do not know they have diabetes and are not under care for the disorder. Each year, about 798,000 people are diagnosed with diabetes.
Although diabetes occurs most often in older adults, it is one of the most common chronic disorders in children in the United States. About 123,000 children and teenagers age 19 and younger have diabetes.
What Is Diabetes?
Diabetes is a disorder of metabolism -- the way our bodies use digested food for growth and energy. Most of the food we eat is broken down by the digestive juices into a simple sugar called glucose. Glucose is the main source of fuel for the body.
After digestion, the glucose passes into our bloodstream where it is available for body cells to use for growth and energy. For the glucose to get into the cells, insulin must be present. Insulin is a hormone produced by the pancreas, a large gland behind the stomach.
When we eat, the pancreas is supposed to automatically produce the right amount of insulin to move the glucose from our blood into our cells. In people with diabetes, however, the pancreas either produces little or no insulin, or the body cells do not respond to the insulin that is produced. As a result, glucose builds up in the blood, overflows into the urine, and passes out of the body. Thus, the body loses its main source of fuel even though the blood contains large amounts of glucose.
What Are the Different Types of Diabetes?
The three main types of diabetes are:
Type 1 Diabetes
Type 1 diabetes (once known as insulin-dependent diabetes mellitus or juvenile diabetes) is considered an autoimmune disease. An autoimmune disease results when the body's system for fighting infection (the immune system) turns against a part of the body. In diabetes, the immune system attacks the insulin-producing beta cells in the pancreas and destroys them. The pancreas then produces little or no insulin.