Also known as: adult-onset diabetes and non-insulin dependent diabetes mellitus (NIDDM) (Note: These terms are now outdated).

Type 2 diabetes is more common in adults aged 50 and older, although it can occur in children and adolescents as well. Being overweight or obese and leading a sedentary (i.e., nonactive) lifestyle are major risk factors for developing type 2 diabetes, as is having a family history of the disease. People of African-American, American Indian, Asian American, Latino, and Pacific Islander background are more likely to develop type 2 diabetes.

Type 2 diabetes is the most prevalent form of the disease, accounting for 90 to 95% of all diabetes cases in America. Unlike type 1 diabetes, where destruction of the pancreas reduces and eventually stops the supply of the hormone insulin, most people with type 2 diabetes are still able to produce insulin at diagnosis. However, the insulin they produce is unable to perform its primary job, which is helping the body's cells use glucose for energy. Usually this is due to a problem with the body’s insulin receptors, the location on cells where insulin binds so that glucose can enter (although less frequently there may be a problem with the chemical makeup of the insulin itself). This condition is called insulin resistance.

If glucose can't be absorbed by the cells, it builds up in the bloodstream instead, and high blood sugar is the result. The pancreas keeps increasing insulin production in an effort to keep up with rising blood sugar levels, and high circulating levels of insulin (known as hyperinsulinemia) develop. Hyperinsulinemia increases the risk of cardiovascular disease and other health problems.

Over time, the high blood glucose levels from uncontrolled diabetes can cause serious long-term health problems with virtually every system in your body. Eventually, they may cause damage to the insulin-producing beta cells of the pancreas, reducing insulin output. An early diagnosis is important to prevent some of the other more serious complications of diabetes, which include heart disease, high blood pressure, nerve damage, and kidney failure. Fortunately, in many cases type 2 diabetes can be adequately controlled through a combination of proper nutrition, exercise, and metformin - which your doctor may prescribe - which is usually the first line of treatment. However, some people with type 2 diabetes do require oral medications or insulin injections.

Although the vast majority of individuals with type 2 diabetes are adults, children and adolescents are increasingly at risk for the disease due to growing childhood weight problems and sedentary lifestyles.