Diabetes has been known since antiquity, when it was so named from the Greek diabainein, meaning “to siphon,” based upon one of the characteristic symptoms of the disease, frequent and excessive urination. Later the designation of some varieties of the disease was lengthened to diabetes mellitus, the additional term stemming from the Latin for “sweetened by honey” and referring to the sweet smell of the urine of diabetics.

Diabetes mellitus is associated with such an unusual urine quality because diabetics either are unable to produce a sufficient amount of insulin or the action of the insulin they do produce is in some way hindered, resulting in elevated levels of glucose in the blood (hyperglycemia). Insulin, which is typically generated in areas of the pancreas called the islets of Langerhans, is required for the glucose to reach muscle and adipose cells, where it would normally serve as fuel, and when it is absent or does not function properly, the cells essentially starve as the simple sugar builds up in the bloodstream and then is excreted with the urine, giving the substance a sugary smell.

Diabetes mellitus is usually not considered a single disease, but rather a group of three different disorders that appear to have different causes though they result in similar symptoms. Type I insulin-dependent diabetes, formerly known as juvenile-onset diabetes, accounts for only 5 to 10 percent of all diabetics. The condition typically develops suddenly and often initially appears in people under the age of 30, though it may occur at any age. Type I diabetics have lost the ability to produce insulin due to damage to the pancreas and the beta cells it normally contains that manufacture the important substance. Scientists have not yet determined specifically what causes the destruction of the pancreatic beta cells, but several possibilities have been suggested including genetics, autoimmune disorders, and viruses.

Type II noninsulin-dependent diabetes accounts for the vast majority (90 to 95 percent) of diabetes cases. Unlike the Type I form of the disease, this type of diabetes comes on gradually and is associated with obesity and aging, though there also appears to be a strong genetic component to the condition. The beta cells of Type II diabetics are intact and produce insulin, but the other cells in their bodies have lost the ability to respond to the substance. Since they do not generally suffer form a lack of insulin, however, Type II diabetics do not usually need insulin injections, though they may be utilized in severe cases. Much more commonly, the disease is controlled with diet and exercise.

Gestational diabetes is a temporary form of diabetes that develops during pregnancy and usually disappears after childbirth. An estimated 135,000 American women develop the condition annually, making it one of the primary health concerns associated with pregnancy. Similar to Type II diabetes, being overweight appears to be a significant risk factor for gestational diabetes, as is being related to a diabetic or being a member of certain ethnic groups, including Hispanic, African American, and Native American.

Diabetes Mellitus at 40x Magnification - Insulin injections are essential for the survival of individuals with Type I diabetes, and before they became available in the early twentieth century, the vast majority of Type I diabetics died shortly after onset of the disease.

Diabetes Mellitus at 20x Magnification - Women with gestational diabetes that do not receive treatment tend to give birth to unusually large children and can have more difficulties during labor and childbirth. These babies are also at higher risk to develop diabetes and other health problems later in life.