Type 2 diabetes is caused by insulin resistance, in which the body does not properly use insulin. Type 2 diabetes 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. Some types of 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.