Type 1 diabetes

According to statistics, of the more than 21 million people with diabetes in the United States, about 5 percent to 10 percent have type 1 diabetes. Although type 1 diabetes can develop at any age, it most commonly appears in children, adolescents and young adults. About one of every 400 to 600 children and adolescents in the United States has type 1 diabetes.

What causes type 1 diabetes?

In type 1 diabetes, the body has little or no insulin because the immune system - which normally fights harmful bacteria or viruses - has attacked and destroyed the insulin-producing cells in the pancreas, a gland located just behind the stomach.

Researchers believe that factors such as genetics, diet and exposure to certain viruses all may be involved in triggering type 1 diabetes. Because type 1 diabetes typically appears in the wake of an infection, the immune attack on insulin-producing cells may be a consequence of the immune system's reaction to the earlier infection. Abnormal antibodies have been found in the majority of patients with type 1 diabetes. Antibodies are proteins in the blood that are part of the body's immune system.

In persons with type 1 diabetes, the beta cells of the pancreas, which are responsible for insulin production, are attacked by the misdirected immune system. It is believed that the tendency to develop abnormal antibodies in type 1 diabetes is, in part, genetically inherited. Exposure to certain viral infections, like mumps and Coxsackie viruses or other environmental toxins may serve to trigger abnormal antibody responses that cause damage to the pancreas cells where insulin is made. These antibodies can be measured in the majority of patients, and may help determine which individuals are at risk for developing type 1 diabetes.

Lack of insulin results in diabetes because of the vital role insulin plays in making glucose - the body's fuel - available to cells. During digestion, your body transforms the carbohydrates from food into different types of sugar molecules. One of these sugar molecules is glucose, the main energy source for your body. Glucose is absorbed directly into your bloodstream after you eat, but it can't enter your cells without the help of insulin.

The pancreas normally produces insulin continuously, raising its output in response to the increase in blood sugar that occurs after you eat. This extra insulin "unlocks" your cells so that more sugar can enter, providing your body with energy as well as maintaining a normal level of sugar in your blood. When your pancreas functions normally, your blood glucose fluctuates in response to exercise, stress, infections, food and a variety of other factors. But your hormonal system - including but not limited to the insulin-producing pancreas - continuously makes complex adjustments that keep your blood sugar levels within set limits.

Those with type 1 diabetes must rely on insulin medication for survival.