Diabetes is a common group of chronic metabolic diseases that cause high blood sugar (glucose) levels in the body due to defects in insulin production and/or function. Insulin is a hormone released by the pancreas when we eat food. Insulin allows sugar to go from the blood into the cells. If the cells of the body are not using insulin well, or if the body is unable to make any or enough insulin, sugar builds up in the blood.
Symptoms include excessive thirst, hunger, and urination; fatigue; slow-healing sores or cuts; and blurry vision.
If diabetes develops quickly, as happens with type 1 diabetes, people may also experience quick weight loss. If diabetes develops slowly, as in type 2 diabetes, people may not be diagnosed until symptoms of longer-term problems appear, such as a heart attack or pain, numbness, and tingling in the feet.
Long-term complications of diabetes can include kidney failure, nerve damage, and blindness.
Diabetes is categorized into categories:
Type 1 Diabetes
This type of diabetes is categorized as an autoimmune disease and occurs when the body’s misdirected immune system attacks and destroys insulin-producing beta cells in the pancreas. Although genetic or environmental triggers are suspected, the exact cause of type 1 diabetes is not completely understood. Type 1 accounts for only five to 10 percent of diabetes cases in the United States, and while it can occur at any age, most patients are diagnosed as children or young adults. People with type 1 diabetes must take insulin daily to manage their condition.
Type 2 Diabetes
This type of diabetes most often develops gradually with age and is characterized by insulin resistance in the body. For reasons not yet totally understood, the cells of the body stop being able to use insulin effectively. Because of this resistance, the body’s fat, liver, and muscle cells are unable to take in and store glucose, which is used for energy. The glucose remains in the blood. The abnormal buildup of glucose (blood sugar), called hyperglycemia, impairs body functions. Type 2 diabetes occurs most often in people who are overweight and sedentary, two things thought to lead to insulin resistance. Family history and genetics play a major role in type 2 diabetes.
Gestational diabetes is defined as blood-sugar elevation during pregnancy; it is known to affect about three to eight percent of women. Left undiagnosed or untreated, it can lead to problems such as high birth weight and breathing problems for the baby. All pregnant women are tested for gestational diabetes at between 24 and 28 weeks of pregnancy, as this is when this problem usually develops. Gestational diabetes usually resolves in the mother after the baby is born, but statistics show that women who have gestational diabetes have a much greater chance of developing type 2 diabetes within five to 10 years.
Although prediabetes is not technically diabetes, some experts now consider it to be the first step to type 2 diabetes. This condition is marked by blood sugar levels that are too high to be considered normal but are not yet high enough to be in the range of a typical diabetes diagnosis. Prediabetes increases not only your risk of developing diabetes but also your risk of heart disease and stroke.
Written by: the Healthline Editorial Team
Medically reviewed on May 13, 2014 by Peggy Pletcher, MS, RD, LD, CDE