Type 1 diabetes is a chronic (lifelong) disease that occurs when the pancreas does not produce enough insulin to properly control blood sugar levels.

See also:

• Diabetes
• Gestational diabetes
• Type 2 diabetes

There are several forms of diabetes. Type 1 diabetes used to be called juvenile or insulin-dependent diabetes. Type 1 diabetes can occur at any age, but it is most often diagnosed in children, adolescents, or young adults.

Insulin is a hormone produced by special cells, called beta cells, in the pancreas, an organ located in the area behind your stomach. Insulin is needed to move blood sugar (glucose) into cells, where it is stored and later used for energy. In type 1 diabetes, these cells produce little or no insulin.

Without enough insulin, glucose builds up in the bloodstream instead of going into the cells. The body is unable to use this glucose for energy. This leads to the symptoms of type 1 diabetes.

Within 5 - 10 years, the insulin-producing beta cells of the pancreas are completely destroyed and the body can no longer produce insulin.

The exact cause is unknown, but most likely there is a viral or environmental trigger in genetically susceptible people that causes an immune reaction. The body's white blood cells mistakenly attack the insulin-producing pancreatic beta cells.

Some people will have no symptoms before they are diagnosed with diabetes.

Others may notice these symptoms as the first signs of type 1 diabetes, or when the blood sugar is high:

• Feeling tired or fatigued
• Feeling hungry
• Being very thirsty
• Urinating more often
• Losing weight without trying
• Having blurry eyesight
• Losing the feeling or feeling tingling in your feet

For others, warning symptoms that they are becoming very sick may be the first signs of type 1 diabetes, or may happen when the blood sugar is very high (see: diabetic ketoacidosis):

• Deep, rapid breathing
• Dry skin and mouth
• Flushed face
• Fruity breath odor
• Nausea or vomiting, unable to keep down fluids
• Stomach pain

Low blood sugar (hypoglycemia) can develop quickly in people with diabetes who are taking insulin. Symptoms typically appear when the blood sugar level falls below 70. Watch for:

• Headache
• Hunger
• Nervousness
• Rapid heartbeat (palpitations)
• Shaking
• Sweating
• Weakness