Type 2 diabetes is a chronic (life-long) disease that results when the body's insulin does not work effectively. Insulin is a hormone released by the pancreas in response to increased levels of blood sugar (glucose) in the blood.

See also type 1 diabetes.

Diabetes, a life-long disease for which there is not yet a cure, is caused by a problem in the way the body makes or uses insulin. Insulin is necessary for glucose to move from the blood to the inside of the cells.

Unless glucose gets into cells, the body cannot use it for energy. Excess glucose remains in the blood, and is then removed by the kidneys. Symptoms of excessive thirst, frequent urination, hunger, fatigue, and weight loss develop.

There are several types of diabetes:

• Type 1 diabetes, which requires total insulin replacement in order to live
• Type 2 diabetes, which is related to insulin resistance, obesity, high cholesterol, and high blood pressure
• Gestational diabetes, which occurs during pregnancy

Diabetes affects up to 6% of the population in the U.S. Type 2 diabetes accounts for 90% of all cases.

A main component of type 2 diabetes is insulin resistance at the level of the fat and muscle cells. This means the insulin produced by the pancreas cannot connect with cells to let glucose inside and produce energy. This causes hyperglycemia (high blood glucose).

To compensate, the pancreas produces more insulin. The cells sense this flood of insulin and become more resistant, resulting in high glucose levels and often times high insulin levels.

A person with type 2 diabetes often does not require insulin injections. The primary treatment is exercise and diet. Type 2 diabetes usually occurs gradually. Most people with type 2 diabetes are obese at the time of diagnosis. However, the disease can also develop in lean people, especially the elderly.

Genetics play a large role in type 2 diabetes and family history is a risk factor. However, environmental factors (such as a low activity level and poor diet) can increase a person's risk for type 2 diabetes.

Other risk factors are as follows: race/ethnicity (African-Americans, Hispanic-Americans, Native Americans, Asian-Americans, Pacific Islanders); age greater than 45 years; previously identified impaired glucose tolerance; hypertension (high blood pressure); HDL cholesterol of less than 35 and/or triglyceride level of greater than 250; history of gestational diabetes or babies over nine pounds.