Cause of diabetes
The cause of diabetes is related to either lack of insulin or decreased production of insulin by the pancreas. Insulin is made by the body to regulate the amount of sugar in the blood. High levels of sugar in the blood can seriously affect other body systems.
Having a lifestyle in which one does not exercise very often, sits around most of the day, and consumes diet high in fat and low in dietary fiber is a major cause of diabetes.
Cause of diabetes Type 1 (also known as Insulin dependent diabetes) is killing of the beta cells by the body's own immune system known as an autoimmune reaction. The reaction can be triggered by environmental factors like infection with virus or bacteria, protein in cow's milk, or exposure to toxins. There can be a genetic predisposition to it. According to American Diabetes Association, Caucasians have a greater risk of type 1 diabetes than African-Americans, Native Americans, Asian Americans, and Latinos. Worldwide, Finland and Sardinia have the highest incidence of type 1 diabetes.
Cause of diabetes Type 2 is related to failure of body cells’ response to insulin (insulin resistance), deficiency of insulin or due to abnormal insulin. It is more common in adults aged 50 and older, although it can occur in children and adolescents as well. The exact cause of type 2 diabetes is not known however, family history, obesity and leading a sedentary lifestyle are major risk factors for developing type 2 diabetes. According to American Diabetes 
Association, people of African-American, American Indian, Asian American, Latino, and Pacific Islander background are more likely to develop type 2 diabetes than Caucasians.
Another cause of diabetes can be drugs (steroids, Dilantin, alloxan, streptozocin, and thiazide diuretics), which are toxic to the beta cells of the pancreas. A rare cause of diabetes can be syndromes (for example, Prader-Willi, Down's, Progeria, and Turner's) which can result in a hyperglycemic state.
Secondary types of diabetes can occur due to injury to or surgical removal of the pancreas, inflammation of the pancreas (pancreatitis) or elevated plasma iron associated with an enlarged liver and pigmentation of the skin. Sometimes cardiac failure, hormonal diseases such as Cushing's disease (puffy red face) or acromegaly (large face, long arms and hands) may also become causes of diabetes.
