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 eye problems, nerve damage, gum disease, heart disease, stroke, 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 American Diabetes Association reports that, in people ages 20 and older, non-Hispanic blacks, Hispanics, and Asian Americans are more likely to have diabetes than non-Hispanic whites. Non-Hispanic blacks are, on average, almost two times as likely to have diabetes as non-Hispanic whites of similar age.

Hormones related to the fetus can 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 hypoglycemia, jaundice, respiratory distress syndrome, and low calcium and magnesium levels. 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.