What is the causative agent of diabetes?

There is no single causative agent of diabetes. Type 1 diabetes is an autoimmune disease in which the body's immune system attacks and destroys the cells in the pancreas that make insulin. Type 2 diabetes is a chronic disease that occurs when the body either does not produce enough insulin or does not use insulin well. The exact causes of type 2 diabetes are unknown, but risk factors include obesity, inactivity, family history, and certain genetic variations.