An Egyptian doctor made the first known reference to diabetes, but referred to the condition as the "passing of too much urine."

Type 2 diabetes was previously called non-insulin-dependent diabetes mellitus (NIDDM) or adult-onset diabetes. Type 1 diabetes was previously called insulin-dependent diabetes mellitus (IDDM) or juvenile-onset diabetes. Type 2 diabetes is associated with older age, obesity, family history of diabetes, history of gestational diabetes, impaired glucose metabolism, physical inactivity, and race/ethnicity, but it is increasingly being diagnosed in children and adolescents.

Diabetes can affect many parts of the body and can lead to serious complications such as blindness, kidney damage, and lower-limb amputations. Controlling the levels of blood glucose, blood pressure, and blood lipids and receiving other preventive care can help prevent these complications.

Insulin helps the body use or store the blood glucose/sugar it gets from food.

Being overweight and inactive both increase the chances of developing type 2 diabetes. But by making changes in your lifestyle such as losing weight and being more physically active, you may prevent it. In 2001, the National Institutes of Health completed the Diabetes Prevention Program, which found that these lifestyle changes reduced the risk for diabetes by 58 percent.

The National Institute of Diabetes and Digestive and Kidney Diseases reports that, on average, Mexican Americans (the largest Hispanic/Latino subgroup), American Indians, and Alaska natives are more than two times as likely to have diabetes as non-Hispanic whites of similar age (2002 statistics). Non-Hispanic blacks are, on average, 1.6 times as likely to have diabetes as non-Hispanic whites of similar age.

Hormones related to the fetus cause insulin resistance. In addition, the pancreas can't provide enough insulin. Gestational diabetes indicates an increased risk for type 2 diabetes.

An infant of a mother who was diagnosed with diabetes before pregnancy may develop serious problems, including birth defects. Gestational diabetes, however, usually does not cause birth defects.

Exercise makes the cells more sensitive to insulin. Muscles use more blood sugar during exercise, so the level of sugar decreases, which reduces the need for insulin.