Type 1 diabetes is a chronic (lifelong) disease that occurs when the pancreas does not produce enough insulin to properly control blood sugar levels.
Type 2 diabetes is a chronic (lifelong) disease marked by high levels of sugar (glucose) in the blood. Type 2 diabetes is the most common form of diabetes.
What are the causes of diabetes?
Diabetes is caused by a problem in the way your body makes or uses insulin. Insulin is needed to move blood sugar (glucose) into cells, where it is stored and later used for energy.
When you have type 2 diabetes, the body does not respond correctly to insulin. This is called insulin resistance. Insulin resistance means that fat, liver, and muscle cells do not respond normally to insulin. As a result blood sugar does not get into cells to be stored for energy.
When sugar cannot enter cells, abnormally high levels of sugar build up in the blood. This is called hyperglycemia. High levels of blood sugar often trigger the pancreas to produce more and more insulin, but it not enough to keep up with the body's demand.
People who are overweight are more likely to have insulin resistance, because fat interferes with the body's ability to use insulin.
Type 2 diabetes usually occurs gradually. Most people with the disease are overweight at the time of diagnosis. However, type 2 diabetes can also develop in those who are thin, especially the elderly.
Family history and genetics play a large role in type 2 diabetes. Low activity level, poor diet, and excess body weight (especially around the waist) significantly increase your risk for type 2 diabetes.
Other risk factors include:
- Age greater than 45 years
- HDL cholesterol of less than 35 mg/dL or triglyceride level of greater than 250 mg/dL
- High blood pressure
- History of gestational diabetes
- Previously identified impaired glucose tolerance by your doctor
- Race/ethnicity (African Americans, Hispanic Americans, and Native Americans all have high rates of diabetes Type 2 diabetes is caused by insulin resistance, in which the body does not properly use insulin. Generally, diabetes type 2 is thought to result from a combination of genetic factors along with lifestyle factors such as obesity, high alcohol intake, and being sedentary. Genetic mutations likely affect parts of the insulin gene and various other physiologic components involved in the regulation of blood sugar. Some rare types of diabetes are directly linked to genes.
Diabetes Secondary to Other Conditions. Conditions that damage or destroy the pancreas, such as pancreatitis (inflammation), pancreatic surgery, or certain industrial chemicals can cause diabetes. Polycystic ovaries are highly associated with diabetes. Certain drugs can also cause temporary diabetes, including corticosteroids, beta blockers, and phenytoin. Certain genetic and hormonal disorders are associated with or increase the risk of diabetes.