Diabetes mellitus

Diabetes mellitus (pronounced /ˌdaɪ.əˈbiːtiːz/ or /ˌdaɪ.əˈbiːtɨs/; /mɨˈlaɪtəs/ or /ˈmɛlɨtəs/)—often referred to simply as diabetes—is a condition in which the body does not produce enough, or properly respond to, insulin, a hormone produced in the pancreas. Insulin enables cells to absorb glucose in order to turn it into energy. In diabetes, the body can't use its own insulin as well as it should, doesn't make enough insulin, and sometimes both. This causes glucose to accumulate in the blood, often leading to various complications.^[2][3] The American Diabetes Association reported in 2009 that there are 23.6 million children and adults in the United States—7.8% of the population, who have diabetes. While an estimated 17.9 million in the US alone have been diagnosed with diabetes, nearly one in four (5.7 million) diabetics are unaware that they have the disease.^[3]

Many types of diabetes are recognized:^[3] The principal three are:

• Type 1: Results from the body's failure to produce insulin. It is estimated that 5-10% of Americans who are diagnosed with diabetes have type 1 diabetes. Presently almost all persons with type 1 diabetes must take insulin injections.
• Type 2: Results from Insulin resistance, a condition in which cells fail to use insulin properly, sometimes combined with relative insulin deficiency. Most Americans who are diagnosed with diabetes have type 2 diabetes. Many people destined to develop type 2 diabetes spend many years in a state of Pre-diabetes: Termed "America's largest healthcare epidemic,"^[4]:10-11, a condition that occurs when a person's blood glucose levels are higher than normal but not high enough for a diagnosis of type 2 diabetes. As of 2009 there are 57 million Americans who have pre-diabetes.^[5]

• Gestational diabetes: Pregnant women who have never had diabetes before but who have high blood sugar (glucose) levels during pregnancy are said to have gestational diabetes. Gestational diabetes affects about 4% of all pregnant women. It may precede development of type 2 (or rarely type 1).

• Many other forms of diabetes mellitus are categorized separately from these. Examples include congenital diabetes due to genetic defects of insulin secretion, cystic fibrosis-related diabetes, steroid diabetes induced by high doses of glucocorticoids, and several forms of monogenic diabetes.

All forms of diabetes have been treatable since insulin became medically available in 1921, but there is no cure for the common types except a pancreas transplant, although gestational diabetes usually resolves after delivery. Diabetes and its treatments can cause many complications. Acute complications including hypoglycemia, diabetic ketoacidosis, or nonketotic hyperosmolar coma may occur if the disease is not adequately controlled. Serious long-term complications include cardiovascular disease, chronic renal failure, retinal damage, which can lead to blindness, several types of nerve damage, and microvascular damage, which may cause erectile dysfunction and poor wound healing. Poor healing of wounds, particularly of the feet, can lead to gangrene, and possibly to amputation. Adequate treatment of diabetes, as well as increased emphasis on blood pressure control and lifestyle factors such as not smokingand maintaining a healthy body weight, may improve the risk profile of most of the chronic complications. In the developed world, diabetes is the most significant cause of adult blindness in the non-elderly and the leading cause of non-traumatic amputation in adults, and diabetic nephropathy is the main illness requiring renal dialysis in the United States.